Installation of linear heated detectors. Types and device of linear thermal detectors

There are many types of devices for the early detection of fire foci, which are part of the Installations / Systems of the APS, which, in turn, are elements. Various fire detectors are also integral parts of gas, water, powder, without which it is impossible to operate both production facilities and public buildings.

In the overwhelming majority of cases, point IPs are used, which determine the appearance of factors for the occurrence of fire focus in limited by its own technical characteristics of a controlled zone, as a rule having a circle or sector. However, in many industrial, warehouse, public buildings / facilities with a greater height, width, they are not applicable, because This exclude their capabilities, restrictions on application.

In such cases, to protect objects by specialists of project organizations, it provides for the use of linear IPs that can fix the appearance of heat, smoke on a straight line / area of \u200b\u200bthe room, even considerable length.

Very similar to the appointment with devices, only to protect the property of citizens / organizations from theft, are linear security detectors designed to control the unauthorized crossing of the perimeter, the active detection zone.

Types of linear fire detectors

To them, on the basis of the definition, which establishes the standards for the design of APS, ACT; It is sounding that the linear fire detector (smoke, thermal) is an IP, which responses to signs of fire in the extended protected zone, includes two types of such technical devices:

• Linear smoke detector (ITD) is a product transmitting an IR-ray instrument / sensor that is sensitive to the transparency of the air environment in the protected room / building. If a smoke occurs exceeds the set threshold value, the optical detector will work, having transmitting an alarm signal to the receiving equipment of the APS settings, the ASPT control and launching devices. In many respects, it is thanks to a thin, straight line of the IR-beam, the location of transceiver devices exactly on one axis such species are called linear IP.

• In addition, they are divided into two types - two- or one-component systems. The first is the traditional layout of a product consisting of two devices: transmitting a continuous optical signal, and receiving it on the opposite side of the room. The second is, when the transmitting and receiving part is made in a single housing, and the transmitted IR ray is sent to a passive reflector / reflector, exactly at the place fixed opposite the instrument. Such linear detectors with reflector are more modern devices requiring smaller costs of the PS loop, product settings.

• Heat detector Linear (ILTT) also has several varieties used in this product the type of heat sensitive cable. They can be contact, electronic, mechanical or optical, while for all the main purpose is the fixation of the threshold or differential increase in temperature along the entire length of the thermocabel. It is worth considering them separately.
• Contact. In them, heat sensitive elements consist of several conductors in low-melting isolation.
• Electronic. They are based on changes in the electric fiber under the influence of heating. Here, thermal elements are a lot of sensors in a stranded cable.
• Mechanical. The sensitive element is a metal tube filled with compressed gas, the pressure of which is increased by increasing the outer medium temperature, which is fixed by the electronic unit sensor transmitting the signal to the device.
• Optical. They use optical fiber cable, whose physical characteristics also change when heated.

Read more on the topic, see the video

Among the linelates of models of linear products both thermal and smoke IPs, many manufacturers have, designed to protect premises in buildings / structures with high.

Many specialists of design organizations, fire protection, assembly enterprises believe that the linear IP can be attributed to linear; Because, although the active zone of detecting factors for the emergence of the fire is sectoral, but the main indicator is the detection range, which is in some models up to 80 m, and this is comparable to the technical characteristics of flue line-line IP.

Pros and cons of linear detectors

The main advantage of linear IP is the ability to protect them objects where the use of point detectors is difficult, or that is impossible due to the design features of buildings / structures, the technological process, the installation places in the premises:

• Smoke. Installation in buildings with large construction volumes, internal, undeveloped spaces, such as assembly and other workshops various productions At industrial facilities, warehouse complexes, logistics centers, exhibition, sports facilities, as well as museum institutions, architectural monuments, where the installation of traditional thermal, smoke IPs on the ceilings for various reasons is impossible or unacceptable. In addition, IPLL is more sensitive to black smoke, have a high response rate to the appearance of pyrolysis products in the air.
• Thermal. ILTT is possible to establish where the installation of point analogs is impossible - in technological galleries, cable tunnels, ventilation boxes, other engineering communications / structures, in other hard-to-reach for regular access / maintenance areas; And also to protect various equipment, even if the surrounding air environment is distinguished by a constant high dusting, gas acquisition, humidity, chemical aggressiveness.
• Flame sensors Install for protection technological equipmentplaced on the external sites of industrial enterprises, incl. To work in rigid climatic conditions.

The disadvantages of linear detectors include the high cost of the kit, which, however, pays off due to the fact that one product replaces several, and even more than a dozen chimneal, thermal IP based on the protected area of \u200b\u200bthe room.

The varieties of linear detectors

Among the products implemented today in the market of components of the APS components, the following models should be allocated, characterized by good technical specifications, reliability, simplicity in maintenance, maintainability:

• IP-104 / ILTT from the company "Fleymstop" (Moscow) with a possible length of up to 3 (!) Km. Temperature range of response from + 68 to 185. Thermocabel - twisted pair with steel residential with copper and tin spraying. The main shell is PVC, protective for various modifications - nylon (for external installation, aggressive media), polypropylene (for chemically active zones), in steel braid - to protect against damage. Resistant to external temperatures up to + 125. Diameter - from 3, 6 to 4, 5 mm depending on the outer shell. Weight - up to 20 kg / 1 km. Protected from electromagnetic tip.
• IP-104 "Granat - Thermocabel" manufactured by the company "Spetspribor" (Kazan). Maximum use length - up to 2 km. The response temperature is from 68 to 180. The maximum width of the protection zone is up to 7, 6 m, recommended to 5 m. Outer diameter - 5 mm.
• ILTT XCR from GC "FiOCHER" (Moscow). Used Length of IP up to 1220 m. External diameter - 4 mm. The outer sheath of a fluoropolymer resistant to aggressive chemical environments.
• Thermocabel PhSC-155-ECP from Protectowire. Length of the loop - up to 2 km. Diameter - 4 mm.
• IPDL D / II-4P. The most common fire detector of this species, produced for more than two decades of the NPF "POLISERVIS" from St. Petersburg, consisting of two blocks - an IR transmitter and receiver. Range - up to 150 m. Protection - IP
• IEPL-52M production of "IVS SpecialAvtomatika". One-component linear detector, in the kit of which the transceiver unit, made in one case, reflector. The range is up to 80 m, the width of the protection zone is up to 9 m.
• IP 212 "Trion-L2-MK" "SMD companies" is intended to protect explosion hazardous premises. Controlled zone - up to 900 square meters. m. Protection - IP
• IP 212-125 (6500R) from the company "SensorSeys". One-component device of a new generation. Distance - up to 70 m. Protection - IP
• Arton dl. Linear single-component smoke IP with a range of up to 100 m.
• Ipdl-Ex. Manufacturer - NVP "Car". A two-component device intended for installation in explosive rooms. The range of this linear detector is up to 150 m.

In addition to these models / brands, many different products are presented in the fire equipment market, therefore, for optimal selection, it is necessary to proceed from the characteristics of buildings / structures, external installations / equipment, upcoming installation conditions, operation and further maintenance.

Linear fire detectors: thermal, gas, combined

Installation rules and installations in the premises

The settings for the installation of linear MP are set forth in SP 5.13130.2009, in particular, in relation to the IITL:

• The placement of detectors should be carried out so that there are no different objects between the devices, even temporarily.
• The installation of linear fire detectors in the room with a height of more than 12 m should be carried out in two tiers.
• Installation of IPLLs When protecting zones / rooms, two and more products should be carried out so that the distance between them is not more than 9 m, from the wall - no more than 4, 5 m.

The designation of the linear fire detector depends on the type of IP - thermal, smoke, flame.

Laboratory studies have established that linear detectors are significantly superior to sensitivity, response speeds both thermal and smoke traditional IP.

As a rule, this does not mean the preference of the choice of ILTT / IPDL instead of point IP. Each type has its own tasks, due to both the technical characteristics and the upcoming places of installation, operation and maintenance, which is always taken into account when developing design and estimate documentation, including the cost of various products.

In practice, several types of fire detectors are used in large objects, both point and linear, which contributes to the possibility of connecting to one and the same receiving and control devices, for example, produced by the company "Bolid".

Linear thermal detector (thermocabel) manufactured by Protectowire (USA)

Call for refinement!

Linear thermal detector (thermocabel) Production of the company Protectowire.(USA) is a cable that is designed to detect fires to increase the optical density of the medium during its smoothness, by the value of the ambient temperature anywhere throughout its entire. The thermocabel is a continuous sensor and applies in cases where the conditions do not allow the installation and use of thermal point detectors, and in conditions of increased explosion hazard, the use of thermocabel is the best solution.

Main characteristics

A given response temperature all over;

Issuance of the "Fire" signal on six temperature values;

High resistance to humidity, dust, low temperatures and chemical reagents;

Irreplaceable in explosive zones;

Easy to install and adjust;

Economical, no expenses for operation;

If it is necessary, the extension is simply added to the system;

Does not require maintenance;

Expected service life for more than 25 years;

Has a certificate of SSPB.

Description

The linear thermal detector Protectowire consists of two steel conductors, each of which has an insulating coating from a heat-sensitive polymer. Conductors with an insulating coating are twisted to create a mechanical voltage between them, then covered with protective insulation and placed in a shell to protect against exposure unfavorable conditions Environment.

When the threshold value of the temperature is reached, under the action of conductors pressure, destruction occurs insulating coating From the heat-sensitive polymer, and to the closure of conductors. This happens in the first overheating point on the thermocabel highway. The ProtectOWIRE thermokabel is a maximum thermal detector and therefore allows an alarm signal when the temperature threshold is reached at any point along the entire length of the cable.

Classification of thermocabel

Currently, there are four types of thermocabel: EPC, EPR, XLT, TRI (Tri-Wire ™) differing in the destination and material from which the outer protective sheath is made for use in the most different conditions Environment.

Type EPC.

Thermocabel Type EPC has a vinyl protective shell of a cable that has a good flexibility at low ambient temperatures. The thermocabel is universal and well suited for both industrial and commercial use.

Type EPR.

The thermocabel type EPR has a solid fire-resistant outer shell of polypropylene resistant to the effects of ultraviolet radiation. Created for widespread Industry in places with high ambient temperature. It has high reliability, elasticity, resistant to abrasion and impact of atmospheric factors.

PHSC-190-EPR
PHSC-280-EPR
PHSC-356-EPR

Type XLT.

The thermocabel type XLT has a special outer sheath-resistant to low temperatures. Specially designed for use at extremely low temperatures in the warehouses of refrigerators, freezers, unheated warehouses, as well as in the severe climatic conditions of the north.

TRI type (Tri-Wire ™)

Thermocabel type TRI (Tri-Wire ™) is a combined (two-temperature) thermal detector, which issues from the established temperature thresholds "Attention" and "Fire". The thermocabel has a solid elastic, moisture-fire-resistant outer casing of vinyl, resistant to the effects of most ordinary chemicals.

Technical data

ProTectowire thermokabel installation method

The ProtectOWIRE thermocabel must be laid in solid segments without taps and branches in accordance with the requirements of the fire organs to the location and configuration of the thermocabel in space. In addition to the requirements of separation on the detection zones (definition source), the length of each bit of the thermocabel is limited and controlled by the control device to which the detector is connected.

Norms of installation of the thermocabel (linear thermal detector) according to the NPB 88-2001 *, paragraph 12.37

The ProtectOWIRE linear thermal detector works on the principle of a device with a normally open contact, which is closed when triggered. Therefore, the thermocabel should be used only in those signaling loops that can detect contact closure and transfer the alarm.

The ProtectowIire thermocabel is a contact device with an active resistance distributed over the entire length of the cable, unlike traditional point thermal detectors that change their resistance when responding. Relatively high detector resistance, 1 Ohm for every 1.5 m twisted pair, requires measurements of resistance of each device to which the thermocabel will be connected to determine the maximum allowable thermocabel length in order to avoid exceeding the maximum resistance of the alarm loop.

When using large areas of the thermocabel, the resistance in the loop may exceed the valid values, as a result of which the control panel will constantly issue a "malfunction" signal, or alarm loop will not be able to generate alarm. This problem is solved using the PIM-120 interface modules, to which you can connect up to 2000 meters of thermokabel and PIM - 420D - 1525 meters of thermocabyl.

The ProtectowIire linear thermal detector reacts to a change in the ambient temperature when the fire occurs. Therefore, the assembly materials used should provide adequate support at temperatures not lower than the threshold value. Fasteners are installed every 1.5-3 m, as well as if it is necessary to prevent excessive wire sagging, which causes the tension of the wire in the mounting places. Incorrect installation Or the fastening of the thermocabel can lead to mechanical damage to the detector, for example, in technological zones, warehouses using loading equipment.

The location of the thermocabel.

The ProtectOkire linear thermal detector must be installed in the protective room on the ceiling or walls at a distance of no more than 500 mm from the ceiling. The thermokabel is paving directly above the source of the danger so that it (thermocabel) has exposed to hot air during a fire, or under any horizontal surface that will cause the same radial propagation of heat as the ceiling of the room in which the protection object is located.

In some cases it is very important to detect overheating, in which the equipment failure or the occurrence of the fire is possible. A typical example is the protection of electric motors or rollers of conveyors whose roller bearings are overheated and jammed.

The advantage of the ProtectOWire thermocabel is that it can be installed close to the critical part of the protected object, which provides a quick triggering of the detector.

Laying the detector track

All models of the linear thermal detector Protectowire passed tests in the underwriters laboratory Laboratories (UL, USA) and / or Factory Mutual Research Corporation (FM). According to the results of tests conducted in accordance with the established certification authorities with the requirements of test standards, the maximum allowable distances between the thermocabel laying lines relative to the maximum detector action zone for various applications were determined.

The maximum distance between the Protectowire thermokabels.

When installing the thermocabel outside the premises, it is very important to keep in mind that the ranges made to the NPB 88- 01 are the maximum allowable distance between the location of the thermocabel and should be used as a starting point for designing the location of the detectors. Depending on the specific conditions of application, such as the design and height of the ceiling, physical obstacles, air flows or the requirements of local semi-zero organs, the maximum allowable distance between the thermocabel's tracks may be less. Finally, the track and the distance between the thermocabel lines are determined by the results of engineering assessment.

Installing the ProtectOWire thermokabel on smooth ceilings

When installing thermocabels on smooth ceilings, the distance between parallel sections of the cables should not exceed the maximum permissible value entered in the NPB 88-01. Thus, the thermocabel should be laid at a distance of no more than 1/2 of the established permissible value from all walls (the distance is measured from the right angle) or ceiling overlapsprotruding no more than 50 cm, as shown in Figure:

Design S. boyful overlaps

In structures with beam overlaps, etc. Heat freely lowers along the beams. However, the spread of heat horizontally is difficult due to beams, so in this direction the distance between the thermocabel lines should be less. The thermocabel is paved along the bottom side of the beams, the distance between all the thermocabel lines parallel to the beams should not exceed 50% of the distance between the cable lines deployed on the smooth ceiling

Boyful construction

If the ceiling beams act no more than 100 mm, the ceiling is considered smooth, if more - the thermokabel is laid from the right angle at a distance of no more than 2/3 of the distance when installed on a smooth ceiling. If the beam performs down from the ceiling for a distance of more than 50 cm and less 2.4 m in the center, each compartment formed by the beams should be protected separately.

"Dead zone

The warm air of the jet rises from a fire source to the ceiling, radially spreading. As the air is cooling, the air begins to drop down. The angle where the ceiling and two adjacent walls are connected, forms a zone called the "dead" zone. In most cases, this "dead" zone is a triangle with parties 10 cm. Along the ceiling (measured from the angle) and 10 cm. Down the wall. Do not install Protectowire thermokabel in this zone!

Downstream ceilings

In a room with a lower ceiling or a pointed roof, one or more linear thermal detectors ProtectOWIRE should be installed at a distance of not more than 0.9 m from the highest point of the roof measured by horizontally. The distance between the ProtectOWIRE thermokabel's additional lines, if they are locked, is determined based on the distance measured by horizontally, which is obtained when designing down from the ceiling, and considering the ceiling design.

Building thermocabel

A variety of designs of linear thermal detectors Protectowire and materials from which protecting braids are made, provide resistance to various chemicals, liquids and atmospheric factors and make thermocabelle suitable for a wide range of applications.

Since it is not always possible to accurately determine the effectiveness of the negative impact of aggressive media on the thermocabel, we recommend that the samples are testing at the site installation site to determine: the selected thermocabel models are suitable or not for these environmental conditions.

When designing a detection system to use outdoors, it is necessary to take into account the effects of solar radiation. Direct inhibition of sunlight or so-called "complete radiation" can lead to the heating of the cable or mounting surface to the temperature above the permissible maximum temperature Environment or temperature threshold sensor.

Therefore, preventive measures are very important, such as a protective screen over the cable to reduce the temperature to permissible values. In addition, the screen will slow down the destruction of the protective braid of the thermokabel under the influence of solar radiation. In the models of the EPN and EPR thermokabels in the material from which the protective braid is made, a special inhibitor has been added to protect against ultraviolet radiation and extending the detector's service.

When using a thermocabel outside of rooms, all connections recommended by the method of splicing or through the terminals must be performed in the appropriate connecting boxes. If the cable is installed in conditions high humidityAll connections are performed by splicing using PWSC or PWS insulating tubes or SFTS insulating tape.

Warnings

The linear thermal detector is made of durable material, but it may be damaged when squeezed or puncture. The results of such damage may be externally visible on the conductor and can not immediately appear, but damage to the external protective braid or mechanical load on the wire during installation may later cause false responses.

Therefore, during installation it is impossible:

Leave the cable on the floor, walk on it or put a staircase on it during installation;

Apply non-original fasteners if they are not approved by The ProtectowIire Company;

Lay the thermocabel in places where there is a risk of mechanical damage in technological processes;

Throw fasteners, as this can lead to the destruction of the outer protective braid and the inner insulating layer and, as a result, cause false responses. All attachments should allow the wire to shrink and stretch with temperature fluctuations;

To pull the thermocabel too much, some "sagging" wires between fasteners normally;

Bending the thermocabel at an angle of 90 °;

Use pliers or forceps to flexing the thermocabel. All bends are performed only by hand, the bend radius should not be less than 6.5 cm;

Apply Wire nuts or other similar devices. All compounds must be performed through terminals and / or flexible conclusions of ProtectowIire insulating tubes;

Collect linear thermal detector.

With the development of technologies, new fire-fighting equipment appeared, where the function of the rapid, accurate determination of the ignition is performed by linear thermal detectors (LTI).

The primary task of line detectors is to ensure the safety of premises with a permanent or temporary stay of people, the preservation and protection of material property from fire in the territories of fire protection facilities.

Thermocabel device

The most convenient fire-fighting thermal sensor is the thermocabel. It is used there, where other devices cannot be established, for example, in tanks with combustible substances, on heating mains in nuclear reactors.

The design of the linear thermal fire detector or thermocabel has stable functionality, low operating flow, long service life.

Protecting equipment and objects from fire by controlling the temperature, it forms a certain signal when it changes, makes it possible to eliminate the fire without substantial material damage.

Modern thermocabel, affordable and easy to work, is two twisted trimetallic conductor who have a spraying:

• of steel. Provides tensile strength;
• copper. Electrical conductivity increases, resistance is reduced;
• tin. To increase corrosion resistance;
• memo-sensitive polymer.

Two conductors twisted with each other to preserve the mechanical tension, additionally consist in a shell of nylon or polypropylene, providing reliable cable protection from UV rays. The shell also increases the resistance to chemical aggressive and eating medium. Counteraction to mechanical wear is carried out with the help of braid metal or glass blocks. The temperature range of the linear thermal detector is from ─60 to + 180, which allows to operate the cable in different climatic conditions.

Principle of operation and application

The principle of the thermocabel operation is based on violation of the integrity of the insulating material by overheating under the action of an increase in ambient temperature. As a result of the destruction of the insulation, the conductors are closed, as the signal is sent to the remote. The alarm can be formed on any segment of the cable, regardless of its length. If the alarming fire factors are detected, information transmission with linear thermal detectors is a threshold or analog process.

The fire sensor, corresponding to GOST, in its intended purpose can be installed both indoors and outside on open extent sites. System mode mode fire safety Depends on the linear detector device. The main technical characteristics are sensitivity, inertia, a zone of action (its shape and area), as well as noise immunity.

Wider capabilities give a thermal linear device having a cumulative effect, where the conductor resistance processing unit can be installed outside the control zone. The heating cable that provides the summation of all dangerous factors is widely used to quickly detect a fire on transformer substations, thermal and hydroelectric power plants, aviation hangars.

It is installed on oil and gas enterprises, metallurgical and chemical industries, transport tunnels in hard-to-reach, with increased pollution, dusting places with an aggressive and explosive medium.

Types of linear thermal sensors

The domestic fire market market offers models of linear thermal detectors, differing from the material of the protective shell, the temperature mode of the triggering, control system and control. The manufacturer, focusing on the conditions of application, produces several types of thermal linear fire detectors.

Received the greatest distribution:

• electronic not allowing short circuitbut fixing the change in resistance when heated. The temperature sensor is the material covering the wire having a negative temperature coefficient. The cable acting in conjunction with the electronic control unit creates different temperature thresholds, it easily restores its functionality after short-term thermal impact;
• mechanical linear thermal reusable detector. Temperature control is carried out using an impenetrable long (up to 300 m) metal tubes. The tube is filled with gas, when heated, its pressure increases, it fixes the control unit;
• conventional contact linear disposable detectors. As a temperature sensor, a polymer shell is used, capable of melting with a certain heating, applied to two wires of fate with each other;
• fiber optic linear thermal sensor. Universal optical cable, which is characterized by the operational definition different species Fire. The temperature sensor consists of a survey device with a laser source and a fiber-optic cable with a halogen shell, which makes it possible to conduct thermal control on a large distance. Cable use factors are affordable price, reliability, durability, ease of installation.

You can allocate another pyrotechnic look. Such a linear detector can perform fire extinguishing functions. Pyrotechnic elements are triggered when heated, the valves open and produce a fire extinguishing agent.

Advanced fire fighting equipment guarantees safety from fire to all public, industrial, administrative facilities.

Popular models

Modern thermal models differ in appearance, layer of outer protective shell, application conditions. The most famous brands are Protectowire, fit schools, special equipment, thermocable, etra.

Table. Specifications Thermocabel Protectowire

ILTT type EPC, produced under the Protectowire license, is a universal thermal pipe with PVC sheath. It is used outdoors when conditions natural environment Do not assume the installation of a conventional thermal detector. It has high durability to dust, dust formation, the ability to limit the spread of the flame.

Thermocabel preserves good bending. Keeping the condition of the material, the detector at atmospheric exposure and UV does not require maintenance and extensive costs during operation.

ILTT Type XLT - The view of the thermocabel is specifically designed for operation at extremely low temperatures. The detector module with a super strong polymer shell maintains ─55 ° C, is intended for use in heat-insulated containers, in storage facilities, unceossed industrial buildings, harsh climatic conditions of the North.

ILTT TRI type - thermocabel, is a unique linear thermal detector. A new type of sensors with high chemical resistance capable of resolving the destructive effects of aqueous acids of acid, alkalis, is intended for use in an explosive medium. The thermal wire protected by a metal wicker mesh is able to resist electromagnetic radiation, eliminate static electricity from the surface. Installation requires two-way grounding.

The main elements of the fire alarm system are a device that detects fire on any signs - fire detectors. The effectiveness of the entire fire alarm system as a whole depends on the quality of their work.

S.V.Shevchenko
Head of Technical Department LLC "ASK"

Currently, in Russia, not every object is equipped with an effective system automatic fire extinguishingAnd if the building is old, then without its capital alterations, such a system cannot be built. In such cases, the main severity of the tasks associated with the timely liquidation of the fire falls on the ignition detection system or, in other words, the fire alarm system, the main element of which is fire detectors. It is known that smoke fire detectors are most effective in multiple cases, but sometimes their use is difficult or simply impossible.

Heat fire detectors

Thermal fire detectors react to change in ambient temperature. They are installed in cases where:

• in the controlled volume, the structure of the materials used is such that the dominant factor of the fire is the separation of heat (for example, when combustion of flammable liquids);
• the spread of smoke is hampered due to external conditions (low temperature, large humidity, etc.);
• in the air there is a high concentration of any aerosol particles that are not related to combustion cycles (for example, exhaust gases from car engine engines, construction, technological or water dust).

Maximum thermal fire detectors are often used - devices that provide alarm signal in case of exceeding the ahead of the specified fixed temperature value. It is usually from +54 to +70 ° C. When heated, the electrical circuit is broken (or closed), due to which the alarm is formed. Detectors of this type include instruments domestic production, such as IP-105 and similar to them.

Point thermal fire detectors of maximum action are inexpensive. They are triggered when a certain temperature is reached on a protected object and do not allow to detect a fire at the initial stage of its development. For this reason, at present, the production of the cheapest thermal fire detectors of the maximum action is sharply reduced and their use is limited.

More complex maximum thermal fire detectors are equipped with a thermo-sensitive semiconductor element forming a closed electrical circuit with a negative temperature resistance to which a certain potential difference is applied. With increasing temperature, the resistance of the chain falls, and larger current begins on it. The value of the current is monitored, and when the specified value is exceeded, the alarm is generated.

Linear thermal fire detectors

An even more interesting is the use of linear thermal fire detectors, since linear detection gives unique advantages when used in places of difficult access, places with increased pollution, dust, aggressive or explosive medium. In addition to the above cases, these detectors are used where the cable channels of a large length are stretched at large industrial enterprises, ore conveyors are installed on mining and processing plants, boiler houses on the corner are running, luggage lines are laid in airbases, etc.

The first linear fire detectors were distributed detectors distributed over the length, which generate a warning or alarm when heating the air medium to a temperature corresponding to the melting of the insulation of metal lives of thermocabyl.

The most commonly used linear thermal detectors used in Russia

Term Cabel Protectowire (USA)

To such detectors, distributed over the length of the object, the thermocabellast of the American production Protectowire belongs.

Operating principle

Upon reaching the threshold temperature value, under the action of the pressure of the conductors, the insulating coating of the heat-sensitive polymer occurs, which allows the conductors to contact with each other. This happens in the first overheating point on the thermocabel highway. To trigger the signal, it is not necessary to wait for the heating of a plot having a certain length. The ProtectowIire thermocabel is a maximum thermal detector, and therefore it allows you to generate a signal of the prereversions and alarms when the temperature threshold is reached (+68.3 ° C or +93.3 ° C) at any point along the entire length of the cable. This thermocabel is a single continuous sensor and allows fire to appear or smoke to accurately determine the East. Heating anywhere throughout its entire.

The disadvantages of such a cable include the fact that this is not tunable by temperature system. In addition, finding overheating, the fused steam closes and "dies." In addition, detectors do not distinguish a fire from short circuit.

More modern linear fire detectors are deprived of these drawbacks, but each of them has its own characteristics.

System IP-102-2x2 (Russia)

Fire detector Thermal multipoint IP 102-2x2 is designed to work in fire alarm systems and fire extinguishing together with receiving and control devices that provide work with current combining fire detectors.

Principle of operation and characteristics

The sensitive element of the DPT detector generates a signal (thermoes), the value of which is proportional to the height of the air temperature in the location of the sensor. According to the adopted classification in NPB 76-98 and NPB 85-2000, detectors are differential.

In the pairing unit (BS) there may be 2 detector triggering thresholds: 5 ° C / min and 10 ° C / min.

Inertia of the detector at a temperature of 5 ° C / min. Makes up TSR \u003d 1 25-130 p. At a temperature of 30 ° C / min. The response time is TCP \u003d 20-40 s.

A constructive sensor fire thermoelectric is an electric two-wire cable type twisted pair in fluoroplastic sheath.

Structure

The composition of IP-102-2x2 includes:

• the pairing unit - BS;
• sensor fire thermoelectric multipoint - DPT;
• sensor fire thermoelectric point (trumina) - DPT-T;
• switching box - QC;
• detector Fire Handmade Contact - IPR-K;
• sensor thermal contact - DTK 1.02 (+70 ° C), DTK 2.02 (+90 ° С);
• device control finite - ukk.

The detector can be used in rooms with ordinary and with aggressive environments, and at objects having explosive areas. But it should be noted that this detector is extremely not desirable to apply indoors where there is a significant fluctuation of temperature, as this may lead to false responses.

TRANSAFE ADW 511 system (Germany)

TRANSAFE ADW 511 is a linear thermal fire detector with threshold and differential temperature control.

Principle of operation

The principle of operation of the system is based on the volume expansion of the gas when heating and the associated pressure increase in the pneumocamera. The detector's response temperature is programmed. The system has a multiple action, when heated, it gives an alarm signal, and upon subsequent inclusion, ready to work again.

Structure

The composition of the system includes:

• touchpad (Senstube);
• detector block (with control unit).

Pressure sensor constantly monitors the pressure in the touch tube. Sensor signals are estimated by the microcyclore. Differential component is processed by electronics.

If the pressure in the sensor tube increases sharply for a short timeThe ADW 511 detector issues an alarm.

Interference related, for example, with weather conditions (slow pressure changes in temperature fluctuations), or pneumatic shoes caused by the high traffic intensity in the tunnel are filtered off.

Self Control

The test motor with the pump increases the pressure in the sensor tube to a specified value with a certain interval. If, for example, due to the disorders of the tightness or damage to the touch tube, the value obtained by the sensor does not correspond to the specified, then the fault signal is fed.

Minimum sensory tube length - 20 m.

Maximum permissible length - 80 m.

The large length of the sensor tube is non-standard, and its increase should be coordinated with the manufacturer.

Alarmline LHD4: (Germany)

The system has the following characteristics:

• can quickly change the response temperature on the control unit;
• not "dying" - finding overheating, gives a signal; After resetting and subsequent inclusion of voltage, the system is ready to work again;
• "distinguishes" a fire from short circuit; constantly conducts self-testing for detecting a chain break or short circuit;
• it can work both autonomously and with any PPK with the help of normally closed / open contacts;
• in case of burnout, only the burnt plot is easily replaced, and not the entire cable;
• easy to install, since mechanical flexibility allows the sensor to repeat all the bends of the controlled zone, economical, does not require special care, easy to start. In addition, the system is resistant to mechanical and chemical impacts, to corrosion, humidity, dust. It is suitable for use in the zones of explosive categories. The system is easily increasing in length.

Structure

The ALARMLINE LHD4 system consists of two elements:

1. Subject self-healing cable that returns to normal operation after finding the overheating area and even after a short stay on fire. The sensor cable is an elongated thermistor that detects the temperature change along its entire length.

2. The block of signal generation is an interface module of a linear thermal detector. If necessary, it can be set at a distance of up to 300 m from the sensor cable using the refractory cable section for connecting the system components.

Principle of operation of the system

With increasing temperature, the value of the electrical resistance parameters is changed. The formed loops of the sensor cable, it means that it decreases, and this change is registered with the LHD4 detector. It activates the alarm at the set response temperature level. The temperature change is recorded along the entire length of the cable, the range of the sensors is up to 300 m.

The sensor cable consists of 4 copper insulated wires. A special polymer with a negative temperature coefficient is applied as an insulating material. The wires are mutually transferred and protected by an outer fire-resistant polymer shell. The processing unit carries out continuous monitoring of insulation resistance m. The conductor, which depends on the ambient temperature. When insulated with a certain temperature set in the processing unit is reached, the latter activates the alarm. This temperature control method allows you to detect local overheating of the sensor cable on any of its plot, and a less significant temperature rise on the extended area. The temperature threshold is mounted depending on the thermocabel length. The processing unit controls the presence of a break or short circuit of the sensor cable and when the cable integrity is impaired, the "malfunction" signal generates.

Summarizing systems

A distinctive feature of the Alarmline systems (Germany) and IP 102-2x2 (Russia) is the ability to summarize the heat-controlled fire factor (temperature) in length. It is known that when combustion, the warm mass of air rise in the form of a sufficiently thin vertical jet over a fire center (the separation angle of warm-air jet is usually 10-20 °). At an altitude of 9-12 m, the warm air from the fire focus is mixed with upper layers Implant air, which leads to a significant expansion of air jet in the horizontal direction and to a decrease in its temperature. For this reason, the detection of a fire at high heights point thermal detectors is inefficient.

In view of the increase in production with the use of expensive equipment and increasing the number of technological staff at enterprises, it is often necessary to take care of the safety of people and technological equipment. Currently, in connection with the tightening of the rules of the security systems, it is often necessary to think about the use of one or another kind of systems.

This article will consider an innovative solution in the field of fire safety - a device represented as a cable.

Linear fire detector, another name of the thermocabel - the device capable of detecting the temperature change, on the site of which it is laid, in cases where it is impossible to establish another kind of fire detectors.

The linear fire detector is a pair of conductors of isolated interim sensitive insulation, clad into an additional protective insulating layer.

Operating principle.

The principle of operation consists in the following when a fire or overheating appears on the site where the thermocabel is used, the insulating layer of each conductor is disrupted under the action of the threshold temperature, while the conductors are closed on a separate or several sections. Control device Deciding on changing the status on the control object.

Classification of the thermocabel by the types of used external insulation,

what significantly affects the application of the detector in specific environmental conditions:

• The EPC type thermokabel, the insulation of which is considered the most universal insulation made of PVC material, which allows it to be used in industrial and civil construction. The shell provides good flexibility when laying the cable at reduced temperatures. It provides adequate fire resistance and moisture resistance.
• The EPR type thermocabel has a polypropylene outer sheath significantly increases fire resistance and does not spread the effects of ultraviolet environmental radiation. As a rule, used in media with aggressive chemicals is not subject to abrasion. At the same time, reliably functions in conditions of elevated ambient temperatures.
• The thermocabel type XLT, the insulation of which is an insulating material from the polymer with the highest way capable of resisting extremely low temperatures. The main purpose of this kind of isolation is the use of a detector on open areas, in the conditions of the Far North, in refrigeration and freezer.
• TRI type thermocabel has an isolation of the EPC type, but the only unique difference from the remaining cable TRI cable (Tri-Wire) is capable of issuing two "predominium" signals and "fire", depending on the installation.
• The thermocabel type XCR in the literal sense of the word includes all the above types of shells. High-quality fluoropolymer sheath, specially designed for special purpose objects, with reduced chimping and gas formation, mechanically resistant to abrasion, with high resistance to reduced temperatures. Also, as well as the EPR shell, stealing the aggressive effects of chemically active substances and ultraviolet exposure. And the ability to use under reduced temperatures allows you to make similarities with an XLT detector. The quality of the shell allows you to emphasize the versatility of the insulation material used.

Classification of thermokabel under the operating conditions

consider below the following figure, which will clearly demonstrate the ability to use one or another isolation in various environmental conditions.

Classification of thermocabel in temperature modes.

In the figure you can see the cable model and the corresponding response temperature, in the operating temperature range.

The advantage of using a linear fire detector:

The thermocacabel has increased sensitivity on temperature changes at its entire length;

The presence of several temperature modes of operation due to the manufacture of devices of various types of manufacture;

Resistance to environmental conditions;

High resistance to low temperature environmental modes;

Low cost and simple system installation solutions, reduced cost of operating costs.

Principles of building system:

Work is based on the principle of working with normally open contacts, so the control device must have a feature of the circuit control of $

It is necessary to take into account the fact that when choosing this detector, it is necessary to take into account its internally resistance due to the long thermocabel, 1 ohms by 1.5 m, which later may affect the length of the thermocabel line on a given area;

When this system is selected on the protected area, it is necessary to be guided by the calculation of the possible resistance of the thermocabyl and evenly distribute the total length on the site into several uniform areas, otherwise the cable section of more than 2000 m can lead to a false response system;

Installation It is necessary to produce a solid plot, not allowing branching, to produce division into zones that are determined by the definition of a fire source in a particular place;

When planning a cable laying, take into account the norms and requirements for the cable laying.

Next, the mounting devices will be considered, which are used in the system of security and fire alarm using a linear fire detector, based on the equipment supplied by the company RROTectowire, approved by VNIIPO EMERCOM of Russia.

Mounting components.

Mounting ZB-4-QC-MP mountingsealed connection of a linear detector and a loop of communication. The execution of the box makes it possible to ensure reliable protection of the connecting node from the external environmental impacts, it helps to ensure a qualitative connection in wide range of operating temperatures.

An example of the application The following in the figure shows that contact connectors enclosed inside the box with such use make it possible to adequately connect the thermocabel and the communication loop, as well as additional resistance, ensuring its integrity.

Crimp Coupling SR-502

its main purpose is to ensure a cable input to the ZB-4-QC-MP mounting zone. A set of steel elements and sealing rings, allows you to get a reliable hermetic connection with a cable and a box, while not damaging the thermo-sensitive cable cable.

Fasteners.

Designed for quick, reliable and at the same time of safe installation, mounting elements allow you to gradually pull the cable during the stretching process, while ensuring the integrity of the thermokabel.

The fastening elements presented below allow without additional stretching and squeezing the insulation of the cable to perform installation.

Waw clamp

appearance of the device Allows you to start and religious fastening of the detector-cable to the surfaces by which it will be laid. The principle of use is that in the inside of the clamp, the material of which, depending on the laying conditions, two types can be applied, the cable is placed and its clamp is placed without pressure on the outer shell.

By type of material used, the clamp can be of two types of nylon (WAW-N) and from polypropylene (WAW-P). Polypropylene clamps are applicable when used in mediums with high temperatures, and nylon in low-temperature media to -40 ° C, and + 88 ° C, respectively, for polypropylene.

There is no features of installation on direct areas, but in the corners there is a shift point of the fastener installation point inside the cable bend by 1.3-2 cm on the intersection of the cable lines, after fixing on direct sections.

Also for direct sites are applicable and more primitive mounting of type OHS.

Linear OHS clamps

it is used to fasten the linear fire detector in direct areas, as recommended by the manufacturer, between the clamps of the WAW type, while ensuring the main support for the detector.

The clamp of type OHS-1 is made of galvanized steel, which justifies its use to use indoors, and the OHS-1/4-SS clamp is made of steel, which justifies its use for use on external installations.

Clamp fixation is made in essence by any mounting product (bolt, screw, hairpin, etc.).

The considered mounting fasteners make it possible to make the thermocabel fastening on the plane, but usually when installation work It is not always possible to produce work only on the plane, or there is no possibility to install a clamp on it, we have to swing the detector to the construction structure, where it will not be possible to fasten the ones or other considerations discussed earlier by methods, resort to the use of clamps that are no additional disorders. Construction mixture will allow the cable laying.

BC Series Clips Set

apply to the laying of the detector to building structures, without disturbing its integrity, and reasonable use of labor costs and installation time. Find applications when installing thermocabel on cables, organized in trays, for metal structures, fache des's design elements, etc.

The principle of attachment is that the clamp of type BC is fixed to the design, and the thermocabel is already fixed to it through the WAW clamp.

At the place of use of the clamp, two types of clamps differ.

Clamp BC-2, material steel, applied to laying the thermocabel indoor.

The BC-3 clamp, galvanized steel, is used for the installation of the thermocabel on the outer structures.

Mounted adhesive type

in cases where it is not allowed to perform a mechanical fastening, and the temperature conditions and environmental conditions allow without special requirements for the material, the fastener consisting of a mounting site and a cable tie, which is glued, to a specialized, industrial glue, which ensures the speed of installation and ease of work.

To ensure the displacement of the thermokabel relative to the mounting point is used L-shaped RMC fastener bracket. L-Holder, at the end of which the WAW clamp or push-button latch has five holes to regulate the displacement distance. As well as all the elements of the fastener, the holder is performed either from sheet steel, or stainless steel, which ensures its possibility of applying both inside and outside the room.

CC-2 mounting clamps.

They are a composite system of fastening elements, which allows you to quickly and conveniently install a linear fire detector along the cable tray with a direct mount to the tray. A typical clamp "Caddy" has a specific bending on one of the edges, which allows when clinging to the edge of the cable tray and hold it to hold it when hanging on the other from its edge of the thermocabel, fixed by fastener with a tag or clamp type WWW.

The manufacturer for these purposes produces two modifications of clamps for tray 1.6-4.0 mm thick and a thickness of 4.0-6.0 mm thick, CC-2N and CC-2W models, respectively.

When using another clamp of the "Caddy" clamp, it is possible to make the attachment to thicker cable tray elements in the same way.

CC-10 mounting clips.

Similar on the principle of working with CC-2 clamps. Additionally, in addition to the previously said, this clamping type has the possibility of additional mechanical impact for fastening the clamp to the tray, when using a bolted connection, in this case the clamp is recommended for mounting the linear fire detector in places of vibration.

Fasteners modifications are represented by two species:

CC-10N are used for wall thickness trays 3.2 - 6.4 mm;

CC-10W are used for wall thickness trays 7.9 - 12.7 mm.

Less complicated, but also the functional method of fastening the thermocabel can be possible in the presence of such products.

Mounting clamp HPC-2.

Resistant to UV radiation of the environment and having a bracket, which allows the tap of the fastening lock to the material with a thickness of 1.5 - 6.4 mm, this clamp will allow without additional labor costs to install a linear fire detector. The thermocabel is embedded in the clamp, which is attached to the appropriate design. Material - nylon.

In the same simple fastening method, it is possible to install the thermocabel using clamps.

Clamps PM-3.

When laying a linear fire detector along sprinkler fire extinguishing systems, a solution was required to solve the thermocabel suspension to the pipe highway, for which such hotuces were introduced.

The system of the clamp in the clamp allows one clamp to fasten the fastening element itself, and the thermocabel is attracted by the second, while there is no contact of the detector with a pipe, and the most important thing is not dragging the place of the cable compression, and the inner insulating layer lived.

Nylon clamps are operated at temperatures from -40 ° C and up to +85 ° C, while the installation temperature is short to be below 0 ° C.

All of the above in one way or another refers to one installation method. Next, we will consider the laying method on the string when using the carrier cable.

N.este-oS.

An exclusive way to supply a linear fire detector is that the carrier cable is already integrated into the detector. Stainless steel threads are located directly under one outer felling. The cable wures the thread with a period of 0.3 m. The cores give the cable an additional rigidity, which will allow you to apply it in places where it is not possible to make fasteners in the usual way.

The installation method is extremely clear, lies in the fact that the ends on the direct portion of the fire detector are attached to fixed parts or brushes and with the help of talrepa produce stretch.

The length of such a plot should not exceed 76 m, otherwise the cable breaks.

Also, to prevent the thermocabel break, over the site of using a linear fire detector, you set supporting elements. The frequency of use of such elements is determined by the operating conditions, which shows the practice of external use. It is recommended to use the element more often to apply in order to ensure support and distribution of the load, from the land, the snow load on the entire length of the thermocabel.