Safety valves relate to protective reinforcement. They are needed to protect the pipeline system from excessive increase in pressure in the system of the pipeline, as well as steam boilers, tanks and other containers. In case of exceeding the pressure, they reset part of the working medium to the environment, or to a special tap. Work in automatic mode.

Safety valve device (on the example of spring FLAMCO PRESCOR S 960)

Principle of Safety Valves

The valve spool is connected to a spring configured to a certain compression at a certain pressure. In the normal state of the pressure of the spring, the spool is tightly pressed to the saddle, the safety valve is closed and does not skip the working environment. Under the influence increased pressureacting on the spool, the spring is compressed, allowing the spool to move away from the saddle and release the working environment along the drill.

In order to avoid the shut-off of the spool to the saddle (this may often happen if the working medium of the pipeline - pairs or overheated water) must be opened periodically forcibly. This is called a "valve undermining". For this, the handles for manual control are installed.

More details with the device and principle of the spring safety valve you can from the video

Types of safety valves

All types of safety valves operate according to the same, described above the principle. But they are divided into subspecies in various parameters.

By type of device that has a tipping on the valve

Spring

The greatest distribution was the spring valves due to the convenience of work and not large sizes. They for adjusting the opening pressure of the valve corresponds to the spring.

There are proportional and full-dimensional spring safety valves.

• In proportional release of the medium, it happens smoothly in proportion to increasing pressure.
• In full-dialing when the pressure is reached, the valve opens immediately and completely, to the distance is more or equal to the cross section of the inlet. Surplus the working medium is quickly reset.

Armchair - cargo.

Armchair Safety Valve

In the lever-cargo safety valves, the limit pressure is adjustable due to the lever and the cargo mounted on the lever. The greater the cargo and the lever, the greater pressure is needed to open the valve and release the working environment. It is applied much less often than spring, as they have large sizes, weight, create vibrations. Do not apply on moving systems, and where the vibration of the pipeline is possible. Used in boilers on fixed steam boilers.

In the height of the lift of the spool

The higher the spool over the seat is capable of climbing, the more its throughput and efficiency. It is very important to pay attention to this parameter of the safety valve, because the valves with the same diameter (DF), but different lifting, have different characteristics.

• Low lining. Valves in which the spool rises from 1/40 to 1/20 sizes of the Du cross section. These are the simplest safety valves that are used in systems without greater requirements for. bandwidthworking mainly with water and other liquids.
• Mid-lining. A spool in such safety valves rises at 1/10 - 1/6 of the valve size. With a complicated design, still do not provide complete permeability, so this type is not very popular.
• High lifting. Provide full permeability due to the rise of the spool to height, equal to or exceeding the diameter of the inlet.

According to the type of discharge of the work environment

• Safety valves open type. Reset the working environment directly into the world around.
• Safety valves closed type. They are sealed K. environment And reset the working environment through a special abandoning channel.

According to the valve triggering method

• Direct valves. The opening / closing of the valve affects the working medium directly, affecting the spool. This is a reliable type of triggering. Unfortunately, it is impossible to apply for large sizes of high pressure pipelines.
• Pulse valves. In their design, an additional device is a pulse valve. In this type of valves, the working medium is discharged only after the pulse valve command. It is used for large diameters and pressures.

Where are the safety valves apply?

The main task of safety reinforcement is to ensure the safety of the use of municipal, industrial, energy equipment, which can be found in oil and gas, chemical, food industries, housing and communal services. In enterprises where used compressed air or steam, the system does not cost without safety valves.

Especially relevant pipeline safety reinforcement in household systems Gas supply, where the pressure disorder can not lead to a breakdown of equipment, but to a serious disaster capable of carrying a variety of human lives. That is why safety reinforcements are produced in accordance with increased quality control requirements.

Order Safety valves wholesale or retail in the company "RU100"!

Our company offers not easy to buy all types of safety valves at affordable prices, but for many years not to worry about breakdowns. We implement only proven and reliable pipe fittingsThat serves long!

It should be noted that usually safety reinforcement works in close symbiosis with. Our specialists will help you understand all the intricacies of the above-mentioned tools so that your system will work successfully for many decades. All our products are equipped with necessary documents and correspond to PCT and EAC standards.

• Our engineers work in the industry since 2008. We know that we sell, and with pleasure we will help you choose the desired model.
• We deliver your order in Russia! Either it is possible to pick up from our.
• Checkout .
• We work with both individuals and legal entities.
• We provide full set documents.
• We accept payment by cash, non-cash, bank cards (with self-delivery)

Have questions? Perhaps the answer is already available in the section. And if not, then ask us:

• by phone 8 800 707 16 86, 8 985 570 35 05;
• by e-mail.

State Standard of the SSR Union

Safety valves
Steam and hot water boilers

TECHNICAL REQUIREMENTS

GOST 24570-81

(ST SEV 1711-79)

State Committee of the USSR on Standards

State Standard of the SSR Union

Valves Safety steam and water boilers Technicalrequirements Safety Valves of Stream and Hot-Water Boilers. Technical Requirements.

GOST 24570-81* (ST SEV 1711-79)

Resolution of the USSR State Committee on Standards of January 30, 1981 No. 363, the deadline for administration is established

from 01.12.1981

Tested in 1986 by the Resolution of the State Standard of 24.06.86 No. 1714, the validity period was extended

until 01.01.92

Failure to comply with the standard is prosecuted by law.

This standard applies to safety valves, installed on steam boilers with absolute pressure above 0.17 MPa (1.7 kgf / cm2) and water heating boilers with water temperature above 388 K (115 ° FROM).

The standard fully corresponds to ST SEV 1711-79.

Standard establishes mandatory requirements.

1. General requirements

1.1. Safety valves and their auxiliary devices corresponding to the requirements of the rules of device and safe operation of steam and hot water boilers, approved by Gosgorthnadzor of the USSR are allowed to protect the boilers.

(Modified edition, change No. 1).

1.2. The design and materials of the elements of the safety valves and their auxiliary devices must be selected depending on the parameters of the working medium and ensure reliability and correctness of the action in the operating conditions.

1.3. Safety valves must be calculated and adjusted so that the pressure in the boiler does not exceed the operating pressure by more than 10%. Pressure is allowed if it is provided for by the calculation of the boiler for strength.

1.4. The design of the safety valve and must be represented by the free move of moving elements Valve and clock the possibility x emission.

1.5. The design of the safety valves of the auxiliary elements should exclude the possibility of arbitrary changes to their adjustment.

1.6. To each safety clause ana and lie , in coordination between the manufacturer and the consumer, GRU pP E identical valves intended for one consumer must attach a passport and instruction manual. Passport must comply with the requirements. The "Basic Technical Data and Characters" section must contain the following data:

name of the manufacturer Il His trademark;

the sequence number of software with the number of numbering the manufacturer or number of the series;

year of manufacture;

valve type;

the conditional diameter at the entrance output from the valve A;

calculated diameter;

calculation area;

view of the medium and its parameters;

characteristic and sizes of spring yield;

para Flow coefficienta. , equal to 0.9 NTA coefficients obtained on the basis of the under test;

permissible backpressure;

pressure value of the beginning opening permissible range of opening start pressure;

characteristics of materials of the main elements eT valve (body, plate, saddle, spring);

valve type test data;

cipher according to the catalog;

conditional pressure;

permissible limits of operating pressure on prugi n.

1.7. On the plate, covering the housing of each safety valve, or the following data should be applied directly on its enclosure:

name of the enterprise-makes la or his trademark;

sequence Number System Number iI manufacturer or number of the series;

valve type;

calculated diameter;

para Flow coefficienta.;

the value of the opening start pressure;

conditional pressure;

diameter of the conditional passage;

flow-pointer arrow;

designation of the main design document and the conditional designation of the product.

Place of labeling and dimensions of marking signs are installed in technical documentation manufacturer enterprises.

2.1.

2.2. Pressure difference full opening and starting the opening of the valve should not be eV Slide sch eN IY:

2.3. Springs PR pinch flap must be protected from unacceptable nation eV AI direct WITH ISSOES OF THE WEDDATION.

At the floor of Oh. opening Valve must be iS. The key is the possible assistance of a lot of contact vitkov Springs.

Design spring valves Must eliminate the possibility of tightening the springs over the set value due to the greatest operating pressure for this valve design.

2.3. (Modified edition, change No. 2).

2.4. Approx enen and al what a lot nna. And the valve rod is allowed.

2.5. In the crue mustache, in places where the condensate is possible, a device should be distincted to remove it.

2.6. (Excluded . № 2).

3. Requirements for safety valves managed using auxiliary devices

3.1. The design of the safety valve and auxiliary devices should exclude the possibility of unacceptable strikes when opening and closing.

3.2. The design of the safety valves should ensure the preservation of the protection function from exceeding pressure during the refusal of any control or regulating body of the boiler.

3.3. Electric safety valves must be equipped with two non-friendly power supplies.

IN electrical circuitswhere the disappearance of the energy causes a pulse that opens the valve, one source of power supply is allowed.

3.4. The design of the safety valve should provide for manually control and in the necessary remote control cases.

3.5. The design of the valve must ensure its closing at a pressure of at least 95% of the operating pressure in the boiler.

3.6. The diameter of the passage pulse valve must be at least 15 mm.

The inner diameter of pulse lines (supply and discharge) should be at least 20 mm and at least a diameter of the output fitting of the pulse valve.

Pulse lines and control lines must have condensate removal devices.

Installation of locking bodies on these lines is not allowed.

Installing a switching device is allowed if with any position of this device pulse line will stay open.

3.7. In safety valves, controlled using auxiliary pulse valves, the installation of more than one pulse valve is allowed.

3.8. Safety valves should be operated under conditions that do not allow freezing, coking and corrosion exposure to the medium used to control the valve.

3.9. When using an external energy source for auxiliary devices, a safety valve must be equipped with no less than two independently active control circuits so that when the other circuit fails, the other circuit has ensured reliable operation of the safety valve.

4. Requirements for supply and discharge pipelines for safety valves

4.1. At the supply and discharge pipelines of safety valves, installation of shut-off authorities is not allowed.

4.2. The design of the pipelines of safety valves will provide the necessary compensation for temperature extensions.

The fastening of the housing and pipelines of the safety valves should be calculated taking into account static loads and dynamic efforts occurring when the safety valve is triggered.

4.3. Sad pipelines for safety valves must have a bias along the entire length towards the boiler. In the supply pipelines, sharp changes in the wall temperature should be excluded when the safety valve is triggered.

4.4. The pressure drop in the supply pipe to the valves of the direct action should not exceed 3% of the pressure starting pressure on the opening valve. In the supply pipelines of safety valves, controlled using auxiliary devices, the pressure drop should not exceed 15%.

When calculating the bandwidth of the valves, the indicated reduction in the pressure of both cases is taken into account.

4.4. (Modified edition, change No. 2).

4.5. The discharge of the working medium of safety valves should be carried out in a safe place.

4.6. Disposal pipelines must be protected from freezing and have a device for condensate.

Installing locking devices on drainage is not allowed.

4.6. (Modified edition, change No. 2).

4.7. The inner diameter of the discharge pipe must be at least the largest internal diameter of the output nozzle of the safety valve.

4.8. The inner diameter of the discharge pipeline must be calculated in such a way that at a flow rate equal to the maximum bandwidth of the safety valve, the backpressure in its outlet nozzle exceeds the maximum backpressure set by the manufacturer's valve manufacturer.

4.9. The bandwidth of the safety valves should be determined by the resistance of the auditter; Its installation should not cause violations of normal operation of safety valves.

4.10. On the site between the safety valve and the speaker, the fitting should be provided for the installation of the instrument measuring pressure.

5. Capacity of safety valves

5.1. The total bandwidth of all safety valves installed on the boiler must satisfy the following conditions:

for steam boilers

G 1 +.G 2 + ...G N.³ D;

for economizers disconnected from the boiler

for hot water boilers

n. - the number of safety valves;

G 1,G 2,G N. - bandwidth of individual safety valves, kg / h;

D. - nominal performance of the steam boiler, kg / h;

The increase in the enthalpy of water in the economizer at the nominal productivity of the boiler, J / kg (kcal / kg);

Q. - nominal thermal conductivity of the hot water boiler, J / h (kcal / h);

g. - Heat evaporation, J / kg (kcal / kg).

The calculation of the bandwidth of safety valves of water boilers and economizers is allowed to be carried out taking into account the ratio of steam and water in a steam mixture passing through a safety valve when it is triggered.

5.1. (Modified edition, change No. 2).

5.2. The bandwidth of the safety valve is determined by the formula:

G. = 10B. 1 × a.× F.(P. 1 +0.1) - for pressure in MPa or

G.= B. 1 × a.× F.(P. 1 + 1) - for pressure in kgf / cm 2,

where G. - bandwidth of the valve, kg / h;

F. - the calculated area of \u200b\u200bthe valve cross section equal the smallest square free cross section in the flow part, mm 2;

a. - the consumption coefficient of steam subject to the area of \u200b\u200bthe valve cross section and determined in accordance with paragraph 5.3 of this standard;

R 1 - Maximum overpressure in front of a safety valve, which must be no more than 1.1 working pressure, MPa (kgf / cm 2);

IN 1 - coefficient, taking into account the physico-chemical properties of the pair when operating parameters in front of the safety valve. The value of this coefficient is chosen in Table. 1 and 2.

Table 1

The values \u200b\u200bof the coefficient IN 1 for saturated pair

R 1, MPa (kgf / cm 2)
R 1, MPa (kgf / cm 2)
R 1, MPa (kgf / cm 2)

table 2

The values \u200b\u200bof the coefficient IN 1 for overheated steam

R 1, MPa (kgf / cm 2)	At a parat N., ° FROM
0,2 (2)	0,480	0,455	0,440	0,420	0,405	0,390	0,380	0,365	0,355
1 (10)	0,490	0,460	0,440	0,420	0,405	0,390	0,380	0,365	0,355
2 (20)	0,495	0,465	0,445	0,425	0,410	0,390	0,380	0,365	0,355
3 (30)	0,505	0,475	0,450	0,425	0,410	0,395	0,380	0,365	0,355
4 (40)	0,520	0,485	0,455	0,430	0,410	0,400	0,380	0,365	0,355
6 (60)		0,500	0,460	0,435	0,415	0,400	0,385	0,370	0,360
8 (80)		0,570	0,475	0,445	0,420	0,400	0,385	0,370	0,360
16 (160)			0,490	0,450	0,425	0,405	0,390	0,375	0,360
18 (180)				0,480	0,440	0,415	0,400	0,380	0,365
20 (200)				0,525	0,460	0,430	0,405	0,385	0,370
25 (250)					0,490	0,445	0,415	0,390	0,375
30 (300)					0,520	0,460	0,425	0,400	0,380
35 (350)					0,560	0,475	0,435	0,405	0,380
40 (400)					0,610	0,495	0,445	0,415	0,380

or determined by the formula for pressure in MPa

for pressure in kgf / cm 2

where TO - Adiabat index 1.35 for saturated steam, 1.31 for superheated steam;

R 1 - maximum overpressure in front of a safety valve, MPa;

V. 1 - the specific volume of steam in front of the safety valve, m 3 / kg.

The formula for determining the bandwidth of the valve should be applied only under the condition: R 2 +0,1)£ (R 1 +0,1)b. kr for pressure in MPa or ( R 2 +1)£ (R 1 +1)b. kr for pressure in kgf / cm 2, where

R 2 - Maximum overpressure behind the safety valve in the space in which steam from the boiler expires (when exposed to the atmosphere R 2 \u003d 0 MPa (kgf / cm 2);

b. Cr - critical reference ratio.

For saturated para b. kr \u003d 0,577, for overheated steam b. kr \u003d 0.546.

5.2. (Modified edition, change No. 2).

5.3. Coefficient a. Take equal to 90% of the value obtained by the manufacturer based on the tests conducted.

6. Monitoring methods

6.1. All safety valves should be tested for strength, density, as well as tightness of the gland compounds and sealing surfaces.

6.2. The volume of valve tests, their order and control methods must be established under the technical conditions on the valves of a specific size.

Safety valve

Installation conditions:

operating pressure: 40.5 bar

Calculation parameters:

Side UASA: PN / CL Cl 600,
Calculate Pressure: 58.97 bar

Calculate Pressure: 6.55 bar
Corrosion thickness: Housing - 0.1 mm, saddle / nozzles: 0.1 mm

hole diameter: 102,61 mm
Input X output (DN): 6 "x 8"
Installation pressure: 47.58 bar


Release pressure: 53,351 bar

Wednesday:

wednesday: Water
Test. Temperature at P0: 267.94 ° C
Molecular weight: 18,02

Overheated pairs:

Compressibility coefficient: 0,915
Specific volume: 0,05099 m³ / kg
Adiabstract index: 1.28

required performance: 189900 kg / h

Calculated Area: 79.68 (cm²)
Useful performance: 197076 kg / h
Reaction force: 60535 N
Noise level: 155 dB

Materials:

Safety valve

Installation conditions:

operating pressure: 40.5 bar
Max. Temperature OCD. Environments: -49/40 ° С

Calculation parameters:

calculated temperature: -50 ... +400 ° С
Side UASA: PN / CL Cl 600,
Calculate Pressure: 58.97 bar
Discharge side: PN / CL Cl 150,
Calculate Pressure: 6.55 bar

Sizes, type and specifications:

hole diameter: 102,61 mm
Input X output (DN): 6 "x 8"
Installation pressure: 48,56 bar
Flanges, Used Utah: ANSI 600 RF X ANSI 150 RF
Productivity factor for gas and steam: 0,975
Output pressure: 54,429 bar
Overpressure / Drop: 10/10 (% of P)
Flow coefficient for gas and steam: Kd \u003d 0,975

Wednesday:

wednesday: Water
Test. P0: 269.24 ° C
Molecular weight: 18,02

Overheated pairs:
Digging Temperature: 371 ° C
Compressibility coefficient: 0,914
Specific volume: 0.04991 m³ / kg
Adiabstract index: 1.28

Valve performance:

required performance: 193700 kg / h
Selected area: 82.69 (see)
Calculated Area: 79.62 (see)
Useful performance: 201168 kg / h
Reaction force: 61830 N
Noise level: 156 dB

Materials:

Safety valve

Installation conditions:

operating pressure: 40.5 bar
Max. Temperature OCD. Environments: -49/40 ° С

Calculation parameters:

calculated temperature: -50 ... +400 ° С
Side UASA: PN / CL Cl 600,
Calculate Pressure: 58.97 bar
Discharge side: PN / CL Cl 150,
Calculate Pressure: 6.55 bar
Corrosion thickness: Case - 0.1 mm, saddle / nozzles - 0.1 mm

Sizes, type and specifications:

valve Type: 281-I
Hole diameter: 102.61 mm
Input X output (DN): 6 "x 8"
Setting pressure: 46.6 bar
Flanges, Used Utah: ANSI 600 RF X ANSI 150 RF
Productivity factor for gas and steam: 0,975
Output pressure: 52,273 bar
Overpressure / Drop: 10/10 (% of P)
Flow coefficient for gas and steam: Kd \u003d 0,975

Wednesday:

wednesday: Water
Test. P0: 266,65 ° C
Molecular weight: 18,02
Compressibility coefficient: 0,915
Overheated pairs:
Digging Temperature: 371 ° C
Compressibility coefficient: 0,915
Specific volume: 0.05206 m³ / kg
Adiabstract index: 1.28

Valve performance:

required performance: 186000 kg / h
Selected area: 82.69 (see)
Calculated Area: 79,66 (cm²)
Useful performance: 193094 kg / h
Reaction force: 59228
Noise level: 156 dB

State Standard of the SSR Union

Safety valves
Steam and hot water boilers

TECHNICAL REQUIREMENTS

GOST 24570-81

(ST SEV 1711-79)

State Committee of the USSR on Standards

State Standard of the SSR Union

Valves Safety steam and water boilers Technical Requirements Safety Valves of Stream and Hot-Water Boilers. Technical Requirements.

GOST 24570-81* (ST SEV 1711-79)

Resolution of the USSR State Committee on Standards of January 30, 1981 No. 363, the deadline for administration is established

from 01.12.1981

Tested in 1986 by the Resolution of the State Standard of 24.06.86 No. 1714, the validity period was extended

until 01.01.92

Failure to comply with the standard is prosecuted by law.

This standard applies to safety valves, installed on steam boilers with absolute pressure above 0.17 MPa (1.7 kgf / cm2) and water heating boilers with water temperature above 388 K (115 ° FROM).

The standard fully corresponds to ST SEV 1711-79.

Standard establishes mandatory requirements.

1. General requirements

1.1. Safety valves and their auxiliary devices corresponding to the requirements of the rules of device and safe operation of steam and hot water boilers, approved by Gosgorthnadzor of the USSR are allowed to protect the boilers.

(Modified edition, change No. 1).

1.2. The design and materials of the elements of the safety valves and their auxiliary devices must be selected depending on the parameters of the working medium and ensure reliability and correctness of the action in the operating conditions.

1.3. Safety valves must be calculated and adjusted so that the pressure in the boiler does not exceed the operating pressure by more than 10%. Pressure increases, if it is provided for by the calculation of the boiler for strength.

1.4. The design of the safety valve should provide free movement of the rolling elements of the valve and eliminate the possibility of their emission.

1.5. The design of safety valves and their auxiliary elements should exclude the possibility of arbitrary changes to their adjustment.

1.6. To each safety valve or, in coordination between the manufacturer and the consumer, the group of identical valves intended for one consumer must be attached to the passport and instruction manual. The passport must comply with the requirements of GOST 2.601-68. The "Basic Technical Data and Characteristics" section should contain the following data:

name of the manufacturer or its trademark;

year of manufacture;

valve type;

conditional diameter at the inlet and outlet of the valve;

calculated diameter;

calculation area;

view of the medium and its parameters;

characteristics and sizes of spring or cargo;

para Flow coefficienta. , equal to 0.9 coefficient obtained based on tests carried out;

permissible backpressure;

the value of the opening start pressure and the permissible range of opening starting pressure;

characteristics of materials of the main elements of the valve (body, plate, saddle, spring);

valve type test data;

cipher according to the catalog;

conditional pressure;

permissible limits of operating pressure on the spring.

1.7. On the plate attached to the body of each safety valve, the following data should be applied directly on its enclosure:

name of the manufacturer or its trademark;

sequence number on the numbering system of the manufacturer or number of the series;

year of manufacture;

valve type;

calculated diameter;

para Flow coefficienta.;

the value of the opening start pressure;

conditional pressure;

diameter of the conditional passage;

flow-pointer arrow;

case material for reinforcement made of steel with special requirements;

designation of the main design document and the conditional designation of the product.

Place of labeling and dimensions of marking signs are established in the technical documentation of the manufacturer.

1.6, 1.7. (Modified edition, Change № 1).

2. Requirements for direct safety valves

2.1. The design valve design should provide a device for checking the operation of the valve during the boiler operation by compulsory opening of the valve.

The possibility of forced opening should be provided with 80% of the opening start pressure.

2.1.

2.2. The pressure difference of full opening and starting the valve opening should not exceed the following values:

15% of the opening start pressure - for boilers with a working pressure not higher than 0.25 MPa (2.5 kgf / cm 2);

10% pressure start opening - for boilers with a working pressure above 0.25 MPa (2.5 kgf / cm 2).

2.3. Surplies of safety valves must be protected from unacceptable heating and direct impact of the working environment.

With the full opening of the valve, the possibility of mutual contact of the springs turns should be excluded.

The design of spring valves should exclude the possibility of tightening the springs over the set value due to the greatest operating pressure for this valve design.

2.3. (Modified edition, change No. 2).

2.4. The application of the surping seal of the valve rod is not allowed.

2.5. In the body of the safety valve, in the places of the possible accumulation of condensate, a device must be provided to remove it.

2.6. (Excluded . № 2).

3. Requirements for safety valves managed using auxiliary devices

3.1. The design of the safety valve and auxiliary devices should exclude the possibility of unacceptable strikes when opening and closing.

3.2. The design of the safety valves should ensure the preservation of the protection function from exceeding pressure during the refusal of any control or regulating body of the boiler.

3.3. Electric safety valves must be equipped with two non-friendly power supplies.

In electrical circuits, where the disappearance of the energy causes a pulse that opens the valve, one source of power supply is allowed.

3.4. The design of the safety valve should provide for manually control and in the necessary remote control cases.

3.5. The design of the valve must ensure its closing at a pressure of at least 95% of the operating pressure in the boiler.

3.6. The diameter of the passage pulse valve must be at least 15 mm.

The inner diameter of pulse lines (supply and discharge) should be at least 20 mm and at least a diameter of the output fitting of the pulse valve.

Pulse lines and control lines must have condensate removal devices.

Installation of locking bodies on these lines is not allowed.

Installing the switching device is allowed if, with any position of this device, the pulse line will remain open.

3.7. In safety valves, controlled using auxiliary pulse valves, the installation of more than one pulse valve is allowed.

3.8. Safety valves should be operated under conditions that do not allow freezing, coking and corrosion exposure to the medium used to control the valve.

3.9. When using an external energy source for auxiliary devices, a safety valve must be equipped with no less than two independently active control circuits so that when the other circuit fails, the other circuit has ensured reliable operation of the safety valve.

4. Requirements for supply and discharge pipelines for safety valves

4.1. At the supply and discharge pipelines of safety valves, installation of shut-off authorities is not allowed.

4.2. The design of the pipelines of safety valves will provide the necessary compensation for temperature extensions.

The fastening of the housing and pipelines of the safety valves should be calculated taking into account static loads and dynamic efforts occurring when the safety valve is triggered.

4.3. Sad pipelines for safety valves must have a bias along the entire length towards the boiler. In the supply pipelines, sharp changes in the wall temperature should be excluded when the safety valve is triggered.

4.4. The pressure drop in the supply pipe to the valves of the direct action should not exceed 3% of the pressure starting pressure on the opening valve. In the supply pipelines of safety valves, controlled using auxiliary devices, the pressure drop should not exceed 15%.

When calculating the bandwidth of the valves, the indicated reduction in the pressure of both cases is taken into account.

4.4. (Modified edition, change No. 2).

4.5. The discharge of the working medium of safety valves should be carried out in a safe place.

4.6. Disposal pipelines must be protected from freezing and have a device for condensate.

Installing locking devices on drainage is not allowed.

4.6. (Modified edition, change No. 2).

4.7. The inner diameter of the discharge pipe must be at least the largest internal diameter of the output nozzle of the safety valve.

4.8. The inner diameter of the discharge pipeline must be calculated in such a way that at a flow rate equal to the maximum bandwidth of the safety valve, the backpressure in its outlet nozzle exceeds the maximum backpressure set by the manufacturer's valve manufacturer.

4.9. The bandwidth of the safety valves should be determined by the resistance of the auditter; Its installation should not cause violations of normal operation of safety valves.

4.10. On the site between the safety valve and the speaker, the fitting should be provided for the installation of the instrument measuring pressure.

5. Capacity of safety valves

5.1. The total bandwidth of all safety valves installed on the boiler must satisfy the following conditions:

for steam boilers

G 1 +.G 2 + ...G N.³ D;

for economizers disconnected from the boiler

for hot water boilers

n. - the number of safety valves;

G 1,G 2,G N. - bandwidth of individual safety valves, kg / h;

D. - nominal performance of the steam boiler, kg / h;

The increase in the enthalpy of water in the economizer at the nominal productivity of the boiler, J / kg (kcal / kg);

Q. - nominal thermal conductivity of the hot water boiler, J / h (kcal / h);

g. - Heat evaporation, J / kg (kcal / kg).

The calculation of the bandwidth of safety valves of water boilers and economizers is allowed to be carried out taking into account the ratio of steam and water in a steam mixture passing through a safety valve when it is triggered.

5.1. (Modified edition, change No. 2).

5.2. The bandwidth of the safety valve is determined by the formula:

G. = 10B. 1 × a.× F.(P. 1 +0.1) - for pressure in MPa or

G.= B. 1 × a.× F.(P. 1 + 1) - for pressure in kgf / cm 2,

where G. - bandwidth of the valve, kg / h;

F. - the estimated area of \u200b\u200bthe valve cross section, equal to the smallest area of \u200b\u200bfree cross section in the flow part, mm 2;

a. - the consumption coefficient of steam subject to the area of \u200b\u200bthe valve cross section and determined in accordance with paragraph 5.3 of this standard;

R 1 - maximum overpressure in front of a safety valve, which must be no more than 1.1 working pressure, MPa (kgf / cm 2);

IN 1 - coefficient, taking into account the physico-chemical properties of the pair when operating parameters in front of the safety valve. The value of this coefficient is chosen in Table. 1 and 2.

Table 1

The values \u200b\u200bof the coefficient IN 1 for saturated pair

R 1, MPa (kgf / cm 2)
R 1, MPa (kgf / cm 2)
R 1, MPa (kgf / cm 2)

table 2

The values \u200b\u200bof the coefficient IN 1 for overheated steam

R 1, MPa (kgf / cm 2)	At a parat N., ° FROM
0,2 (2)	0,480	0,455	0,440	0,420	0,405	0,390	0,380	0,365	0,355
1 (10)	0,490	0,460	0,440	0,420	0,405	0,390	0,380	0,365	0,355
2 (20)	0,495	0,465	0,445	0,425	0,410	0,390	0,380	0,365	0,355
3 (30)	0,505	0,475	0,450	0,425	0,410	0,395	0,380	0,365	0,355
4 (40)	0,520	0,485	0,455	0,430	0,410	0,400	0,380	0,365	0,355
6 (60)		0,500	0,460	0,435	0,415	0,400	0,385	0,370	0,360
8 (80)		0,570	0,475	0,445	0,420	0,400	0,385	0,370	0,360
16 (160)			0,490	0,450	0,425	0,405	0,390	0,375	0,360
18 (180)				0,480	0,440	0,415	0,400	0,380	0,365
20 (200)				0,525	0,460	0,430	0,405	0,385	0,370
25 (250)					0,490	0,445	0,415	0,390	0,375
30 (300)					0,520	0,460	0,425	0,400	0,380
35 (350)					0,560	0,475	0,435	0,405	0,380
40 (400)					0,610	0,495	0,445	0,415	0,380

or determined by the formula for pressure in MPa

for pressure in kgf / cm 2

where TO - Adiabat index 1.35 for saturated steam, 1.31 for superheated steam;

R 1 - maximum overpressure in front of a safety valve, MPa;

V. 1 - the specific volume of steam in front of the safety valve, m 3 / kg.

The formula for determining the bandwidth of the valve should be applied only under the condition: R 2 +0,1)£ (R 1 +0,1)b. kr for pressure in MPa or ( R 2 +1)£ (R 1 +1)b. kr for pressure in kgf / cm 2, where

R 2 - Maximum overpressure behind the safety valve in the space in which steam from the boiler expires (when exposed to the atmosphere R 2 \u003d 0 MPa (kgf / cm 2);

b. Cr - critical reference ratio.

For saturated para b. kr \u003d 0,577, for overheated steam b. kr \u003d 0.546.

5.2. (Modified edition, change No. 2).

5.3. Coefficient a. Take equal to 90% of the value obtained by the manufacturer based on the tests conducted.

6. Monitoring methods

6.1. All safety valves should be tested for strength, density, as well as tightness of the gland compounds and sealing surfaces.

6.2. The volume of valve tests, their order and control methods must be established under the technical conditions on the valves of a specific size.