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The water flow sensor for the pump is an integral part of the equipment designed to protect the device from running dry. The sensor is small and simple design, which allows you to install it even for a beginner.
Features and Benefits of the Water Flow Sensor
Often there are situations in which the pump starts at the moment of complete absence of liquid in the pipeline. This provokes heating of the motor of the unit and its further breakdown. To avoid such situations, a fluid flow sensor should be used. This device works automatically and controls the flow of water inside the pipeline. If the amount of liquid passing through the sensor is less than the norm, the device automatically turns off the pump. Thus, the water flow switch not only prevents the pump from running dry, but also maintains normal operating conditions for the unit.
The benefits of using a sensor include:
- Reducing the electricity consumed by the pump and saving money;
- Protection of equipment from breakdowns;
- Extending the life of the pump.
Among other things, the water flow switch for the pump is distinguished by its modest dimensions, low cost and ease of installation.
Water flow switch - principle of operation and design
The main function of the sensor is to turn off the pumping equipment in the event of a drop in water level or an increase in pressure in the pipeline. If the amount of water increases or the pressure drops, the liquid flow indicator restarts the equipment. Its structural elements are responsible for the stable performance of the tasks assigned to the relay.
The device device consists of the following parts:
- A pipe through which liquid enters the device;
- A membrane that plays the role of one of the walls of the inner chamber of the device;
- Reed switch, which is responsible for opening and closing the circuit in wiring diagram pump;
- Two springs of different diameters - by compressing them, the water pressure is controlled, at which the fluid flow sensor will be triggered.
The principle of operation of the relay is as follows:
- When it enters the internal chamber of the device, water exerts pressure on the membrane, thereby shifting it to the side;
- The magnet located on the back of the membrane gets closer to the reed switch, due to which its contacts close and the pump turns on;
- If the water level drops, then the membrane with the magnet moves away from the switch, which leads to the opening of its contacts and turning off the pump.
Installing a liquid flow detector in a pipeline is quite simple. To do this, you need to study the features of connecting the device and its correct configuration.
Device connection diagram
The performance of a relay is highly dependent on its correct installation. It must be remembered that the device can only be installed on those sections of the pipeline that are located horizontally. In this case, it will be necessary to ensure that the sensor membrane is in a vertical position. Correct scheme The relay connection looks like this:
During installation, the sensor must be connected to the drain part of the pipe by means of a threaded connection. The distance at which the relay must be located from the pipe must be more than 5.5 cm.
On the body of the device there is an arrow indicating the direction of circulation of the liquid. When installing the device, make sure that this arrow coincides with the direction of the water flow in the system. If used for domestic purposes dirty water, then a cleaning filter should be installed in front of the sensor.
Careful attitude to the equipment that provides water supply, significantly extends its working life, guarantees uninterrupted operation of the system. This requires not only timely inspection and proper care, but also equipping the pumps with a full range of protection devices. It is much cheaper to prevent the possibility of a serious breakdown than to repair or buy a new unit. Do you agree?
Installing a water flow switch will protect the engine of both surface and deep pumping equipment. Indeed, most often when a motor burns out, it is easier to buy a new pump than to change it. We will tell you how this important protective device works, how to choose it and include it in an autonomous water supply.
The article contains valuable advice for the installation of pump protection devices against operation in "dry running" conditions. The technology of customization for individual requirements has been disassembled. For better perception A considerable amount of information is accompanied by photographs, diagrams, video reviews and manuals.
In domestic water supply systems, the operation of a pumping station without water that threatens with an accident quite often occurs. A similar problem is called "dry running".
As a rule, the liquid cools and lubricates the elements of the system, thereby ensuring its normal performance. Even a short dry run leads to deformation of individual parts, overheating and failure of the equipment engine. Negative consequences apply to both surface and deep pump models.
Dry running occurs for various reasons:
- wrong choice of pump performance;
- unsuccessful installation;
- violation of the integrity of the water pipe;
- low fluid pressure and lack of control over its level, for which they are used;
- accumulated debris in the pumping pipe.
An automatic sensor is necessary in order to completely protect the device from the threats posed by lack of water. It measures, controls and maintains the constancy of the parameters of the water flow.
Pumping equipment equipped with a sensor has many advantages. It lasts longer, fails less often, consumes electricity more economically. There are also relay models for boilers
The main purpose of the relay is to independently turn off the pumping station in case of insufficient fluid flow power and turn it on after normalization of the indicators.
Design and principle of operation
The sensor has a unique device, thanks to which it performs its immediate functions. The most common modification is the petal relay.
The following important elements are included in the classical structure scheme:
- an inlet pipe that passes water through the device;
- a valve (petal) located on the wall of the inner chamber;
- isolated reed switch that closes and opens the power supply circuit;
- springs of a certain diameter with different compression ratios.
At the time when the chamber is filled with liquid, the force of the flow begins to act on the valve, displacing it around the axis.
The magnet built into the reverse side of the petal comes close to the reed switch. As a result, the contacts are closed, including the pump.
The flow of water is understood as the speed of its physical movement, sufficient to turn on the relay. Reducing the speed to zero, resulting in a complete stop, returns the switch to its original position. When setting the response threshold, this parameter is set taking into account the conditions of use of the device
When the flow of fluid stops and the pressure in the system drops below normal, the spring compression weakens, returning the valve to its original position. Moving away, the magnetic element ceases to operate, the contacts open and the pumping station stops.
Some modifications are equipped with a return magnet instead of springs. Judging by the feedback from users, they are less affected by small pressure surges in the system.
Petal relays are characteristic a large number of pluses. Among them are a simple and unpretentious design, instant response, no delays between repeated responses, the use of an accurate trigger to start equipment.
Depending on the constructive solution there are several other types of relays. These include rotary devices equipped with a paddle wheel rotating in a water stream. The speed of rotation of the blade in them is controlled by touch sensors. In the presence of liquid in the pipe, the mechanism deviates, closing the contacts.
There is also a thermal relay that operates in accordance with thermodynamic principles. The device compares the temperature set on the sensors with the temperature of the working medium in the system.
In the presence of flow, a thermal change is recorded, after which the electrical contacts are connected to the pump. In the absence of water movement, the microswitch disconnects the contacts. Models are characterized by high sensitivity, but they are quite expensive.
Instrument selection criteria
When choosing equipment that controls the strength of the water flow, you should carefully study it. specifications.
Particular attention should be paid to the range operating temperature and the pressure for which it is designed, the diameter of the thread and mounting holes, the protection class, the nuances of the application. It is also important to clarify what materials the product is made of.
Experts consider devices made of brass, stainless steel, and aluminum to be the most reliable and durable. These materials protect the structure from the critical consequences of a frequent phenomenon in plumbing systems - hydraulic shocks.
Considering different modifications of the relay, it makes sense to purchase an option made of metal. The body and working components of such devices are characterized by increased strength.
This fact allows the equipment long time Withstand heavy loads arising due to the significant fluid passing through the sensor.
The pressure value at which the relay operates must correspond to the power installed pump. The parameters of the water flow circulating through the pipeline depend on this characteristic.
It is advisable to choose a device with two springs that controls the operation of the pumping station according to certain lower and upper pressure marks.
The operating temperature range of the sensor directly indicates the possible area of its application. For example, for hot water circuits and heating systems, models with a high boundary temperature are intended. For pipelines with cold water quite enough range up to 60 degrees
Another important criterion worth mentioning is climatic conditions necessary for the operation of the product. This is the recommended air temperature and humidity level that the device needs to provide so that it can work with the best performance.
Maximum permissible loads for a particular device determines the protection class specified in the technical specifications.
When buying a flow sensor, you should check the diameter of the thread section and the dimensions of the mounting holes in the equipment: they must fit perfectly with the elements of the pipeline. The correctness and accuracy of further installation, as well as the efficiency of the relay after installation, depend on this.
Trustworthy Instruments
Among the entire range of relays, two models are most in demand, located in approximately the same price category - about $ 30. Let's consider their characteristics in more detail.
Genyo Lowara Genyo 8A
Development of a Polish company engaged in the production of electronic equipment for control systems. It is intended for application in household water supply systems.
Genyo allows for automatic pump control: starting and shutting down based on actual water consumption, preventing any pressure fluctuations during operation. Also, the electric pump is protected from running dry.
The main purpose is to control the pump and control the pressure in the pipes during operation. This sensor starts the pump when the water flow exceeds 1.6 liters per minute. It consumes 2.4 kW of electricity. The operating temperature range is from 5 to 60 degrees.
Grundfos UPA 120
Manufactured in factories in Romania and China. Maintains the stability of the water supply in rooms equipped with individual water supply systems. Prevents pumping units from idling.
Relay trademark Grundfos is equipped with a high protection class, allowing it to endure almost any load. Electricity consumption in it is about 2.2 kW
The automation of the device starts at a flow rate of 1.5 liters per minute. The boundary parameter of the covered temperature range is 60 degrees. The unit is produced in compact linear dimensions, which greatly facilitate the installation process.
Liquid flow switches are installed for devices that need constant control and compliance with a certain operating mode. Often they complete the equipment at the production stage. However, there are circumstances where a separate mounting of the sensor is required.
Rules for installing relays in the system
Installation safety device, which determines the presence or absence of water flow in the system, is a reasonable step in cases where it is not possible to be constantly present during the operation of pumping equipment.
It is not required only in two cases:
- Water is pumped from a large well with unlimited resources by a low power pump.
- It is possible to independently turn off the unit when the water level drops below the designated norm.
The device is installed on horizontal sections of the pipeline. In this case, it is necessary to ensure that the membrane takes a stable vertical position.
The device is mounted to the drain pipeline using a threaded coupling. Usually a special socket is provided for this.
If there is no hole for mounting the sensor in the pumping equipment, you can replace it with a brass tee. In addition to the relay, a pressure gauge is connected to it, showing the current pressure in the network.
Before proceeding with the direct screwing of the device, it is advisable to seal the thread well with flax or thread sold in specialized departments.
It is better to wind it in a clockwise direction towards the end. This method of fastening increases the reliability of fixation.
In order not to damage the relay, you should screw it very carefully, slightly tightening it with a wrench. The optimal distance between the product and the pipeline is at least 55 mm
When installing the factory sensor, it is necessary to focus on the arrow shown on the case. The direction indicated on it must coincide with the direction of flow of the liquid passing through the device.
If contaminated water is transported through the pipeline, it is recommended to install cleaning filters, placing them near the sensor. Such a move will ensure the correct operation of the product.
At the final stage installation work the dry-running relay is connected to the electrical network:
- a wire core is screwed to the free ends of two groups of contacts;
- a ground is attached to the sensor screw;
- the device is connected to the pump by connecting two devices with an ordinary wire in compliance with.
After connecting to the network, the only thing left is to check the system's performance. The fact that the device is ready for full operation will be indicated by the growth of pressure marks on the pressure gauge and automatic shutdown pump at the moment of overcoming the limit value.
Self-adjustment procedure
There are special bolts in the sensor for adjustment. By loosening or tightening them, you can reduce or increase the compression force of the spring.
Thus, the pressure level is set at which the device will operate.
Almost always, manufacturing companies produce equipment with adjusted settings. Despite this, sometimes additional self-adjustment is required.
In most cases, the setting automatic equipment causes no difficulty.
It is advisable to adhere to the following algorithm:
- drain the fluid from the system until the pressure mark reaches zero;
- turn on the pumping unit and slowly start the water back;
- fix the flow pressure indicator when the pump is turned off by the sensor;
- start draining again and remember the indicators at which the pumping equipment will start working;
- open the relay and adjust with the adjusting bolt the minimum level of compression of the larger spring required to operate the device and start the pump (more compression increases the degree of pressure, less - reduces);
- in a similar way, adjust the compression force of the smaller spring mechanism by setting the boundaries maximum pressure, upon reaching which the relay measuring the water flow will turn off the pump.
After completing all the described manipulations, you should make sure that the adjustments made are correct. To do this, the pipeline is filled with liquid, and then it is drained, evaluating the reaction of the sensor while reaching the set values.
If the test result is not satisfactory, the procedure is repeated.
Having insufficient experience and qualifications, it is better to seek help in adjusting from specialists. They will analyze the specific situation, take into account the technical characteristics of the equipment and select the most correct values of the pressure level.
In order for the pipeline through which the liquid passes to work properly and stably, a regular annual check of the flow sensors is carried out. If necessary, the setting of the operating parameters is adjusted.
Conclusions and useful video on the topic
Structure, components and principles of operation:
The process of connecting the device in stages:
Read more about how to adjust the trigger level in the relay:
A relay that controls the flow of water in the pipeline will significantly increase the usability of pumps and extend their life for a long time. Neglect installation safety device highly undesirable, since it not only automates the operation of the equipment, but also protects it to the maximum from possible problems that occur due to idling.
Do you want to install the flow switch yourself, but are a little confused by the instructions? Please ask your questions, and we and the visitors of our site will try to help you.
Or maybe you have successfully coped with the installation and configuration of the device and want to give useful advice other newbies? Write your comments in the block below, add a photo of the installation or setup process - your experience will be useful to many home craftsmen.
The main task of any water supply system is not only to provide water to the consumer, but also to implement its uninterrupted operation in automatic mode without breakdowns. For this purpose, the commonly used pressure switches and dry running, float devices for monitoring the liquid level are intended. These devices, in addition to automating the operation of the system, protect the pump from dry running and, as a result, from overheating and failure. The water flow switch for the pump is less known and common, but is also designed to automate the operation of the plumbing system and protect its main equipment from failure.
The flow switch is designed to monitor the flow of liquid in systems of cold and hot water supply, heating, cleaning and cooling installations.
Its main purpose is to protect electric pumps, motors and other devices from operation in the absence or small amount of water in the system, leading to overheating and equipment failure.
Fig.1 Appearance of the flow switchThe relays are designed for installation in a pipeline and allows you to automate the process of controlling the supply of liquids in domestic and industrial systems.
The water flow sensor for the pump is used in the following cases.
- If there is no hydraulic accumulator in the system. This does not allow the installation of a pressure sensor designed to be paired with expansion tank, it is better to use a flow sensor to protect the electric pump.
- In low pressure systems. The minimum threshold for triggering typical models of pressure sensors is 1 bar, that is, at a lower pressure in the system, the pump will always be turned off. Flow devices have a wider range of action, which can be expanded with adjustments. This allows the use of equipment protection devices in underpressure systems.
To adjust to work with a wide range of pressures, some petal models are equipped with petals different area providing different resistance to water flow. Sometimes notches are applied to the blade indicating the length. When installed, it is cut to obtain the required set pressure according to the table with various combinations of the length of the petal and the internal diameter of the pipeline.
Figure 2. Flow switch with adjustable blade length - The vast majority of flow relays are designed to operate in heating systems, so the temperature of their working fluid can be 100 C or more.
Device and principle of operation
The principle of operation of the flow switch is based on the mechanical action of the water flow in the pipeline on the sensor that controls the electronic circuit for switching on and off the electric pump. Relays have a different principle of operation and, depending on the design of the sensor, are divided into several types.
Petal relays
One of the most common types, the main elements are lobe sensor with a magnet located in the water flow and a reed switch placed in the device case and reliably isolated.
Fig.3 Petal mechanical relay When the water flow passes through the pipeline, the vertically located petal sensor rotates along its axis and deviates from the vertical position, bringing the built-in magnet closer to the reed switch. Its contacts inside the cylinder close and through the triac (double symmetrical thyristor) the pump is connected to the power source.
In the absence of water in the pipeline, the petal returns to its original position, moving the magnet away from the reed switch and thereby opening its contacts.
This leads to the termination of the supply voltage to the pump through the hemistor, as a result of which it turns off.
Fig. 4 External view of the relay with a reed switch and a sevenistor Rotary relays and flow type sensors
Rotary sensors are mainly used to measure and control fluid flow. Structurally, they are made in the form of a paddle wheel rotating in a fluid flow, its rotation speed is recorded by sensor sensors. Electronic circuit allows to carry out analog, frequency or discrete control of equipment operation.
Fig.5 Rotary sensors Piston devices
The piston is placed in the valve seat and, under the influence of water pressure, moves in a vertical direction to a height proportional to the flow force. Permanent magnet, mounted on the piston, approaches the reed switch and the contacts close in it. Piston units can be installed in horizontal and vertical pipelines due to the built-in return spring that returns the piston to its original position in the absence of flow.
Rice. 6 Working principle and appearance piston relays Water flow switches, unlike pressure and dry running switches, float switches, are not so widely used for automatic control water electric pumps in systems domestic water supply. This is due to the fact that they cannot work independently in the water intake system - to turn them on, it is necessary to create a flow of water and turn on the pump by other devices. Relays are designed to turn off electric pumps and are often built into electronic water supply control units in conjunction with other automation.
Security effective work pumping units are a guarantee of the uninterrupted functioning of the water supply and heating systems they serve. To solve such an important task, pipelines are equipped with additional technical devices, one of which is a water flow sensor (or water flow sensor). Its use allows you to control failures that can periodically occur in pipeline systems, and, accordingly, minimize the risk of failure of pumping equipment.
Purpose and benefits
When operating domestic water pipes, it is not uncommon for the pump to turn on when there is no liquid in the pipes. Such situations, if they occur frequently and continue for a long time, cause the pump motor to overheat and deform its parts, which ultimately leads to the failure of the entire device. The water pumped by pumping equipment simultaneously performs lubricating and cooling functions, therefore, “dry running”, as it is also called, negatively affects the technical condition of both circulation and submersible pumps.
In order to prevent the occurrence of the described situations, they just use a water flow sensor for the pump, which operates in automatic mode. Water flow sensors are successfully used to control work pumping stations serving hot and cold water supply systems, as well as heating systems.
Considered automatic device controls the parameters of the flow of water that passes through it, and in cases where they differ from the normative ones, automatically turns on or off the pumping equipment. Working according to this principle, the sensor not only protects the pumping equipment from "dry running", but also ensures the constancy of the water flow parameters.
Among the advantages of operating pumping equipment on which a fluid flow sensor is installed, one can name:
- reduction in electricity consumption and, accordingly, reduction in the cost of its payment;
- minimizing the risk of failure of pumping equipment;
- increase the service life of pumping equipment.
Design features
The main tasks that water flow control sensors installed in domestic pipelines solve are to turn off pumping equipment at the moment when there is no liquid in the system or its flow pressure exceeds the standard value, and turn it on again when the pressure drops. Effective solution These important tasks are provided by the design of the sensor, which is formed by the following elements:
- a branch pipe through which water enters the sensor;
- a membrane constituting one of the walls of the inner chamber of the sensor;
- reed switch providing closing and opening of the pump power supply circuit;
- two springs of different diameters (the degree of their compression regulates the pressure of the fluid flow at which the water flow switch for the pump will operate).
The device of the above design works as follows:
- Entering the inner chamber of the sensor, the water flow exerts pressure on the membrane, displacing it.
- The magnetic element fixed on the reverse side of the membrane, when it is displaced, approaches the reed switch, which leads to the closure of its contacts and turning on the pump.
- If the pressure of the water flow passing through the sensor drops, then the membrane returns to its original position, the magnet moves away from the switch, its contacts open, respectively, pumping unit turns off.
In pipeline systems for various purposes, sensors that control the flow of water are installed quite simply. The main thing is to choose the right device, paying attention to its operating parameters and characteristics of pumping equipment.
Main characteristics
When choosing water flow sensors to equip the pipeline system, the following parameters should be taken into account:
- material for the manufacture of the body and internal elements;
- operating pressure for which the sensor is designed;
- the temperature range of the liquid for which the device will be used to control the flow;
- protection class and requirements for operating conditions;
- diameter of mounting holes and thread parameters in them.
Each of the above parameters affects the performance of water flow sensors, so it is worth considering them in more detail.
From what material the sensor body and its internal parts are made, depend on the reliability of such a device, its ability to withstand the loads that arise during operation, as well as its durability. When choosing a liquid flow sensor, it is better to give preference to models for the manufacture of which were used various metals – stainless steel, brass or aluminium. During operation, both the body of the flow sensor and its internal elements experience significant pressure from the fluid passing through it. Only durable materials can withstand such a load for a long time. In addition, phenomena such as water hammer are not uncommon in pipelines, the consequences of which can quickly disable the sensor if inappropriate materials were used for its manufacture.
The value of the operating pressure at which the fluid flow sensor can operate correlates with the power of the pump used, so this parameter should be considered Special attention. In addition, this parameter also determines what characteristics the flow of liquid transported through the pipeline will have. Those models of water flow sensors, in the design of which two springs are provided, can control the operation of the pump according to the lower and upper pressure levels. Devices of this type it is better to give preference.
The temperature of the liquid for which the sensor is designed has a direct impact on the application in which applications it can be used. Naturally, when choosing such a sensor for equipping a heating or hot water supply system, one should pay attention only to those models that can work with water heated to a high temperature. For pipelines transporting cold water, use flow sensors designed to work with liquids having a temperature of 60–80 °.
humidity level and temperature regime environment, at which the fluid flow sensor can be operated, are also important parameters. The protection class of such a device indicates what loads it is able to withstand when paired with pumping equipment.
Sensors that control the flow of water, as a rule, are chosen for ready-made pipeline systems or for those whose design has already been developed. That is why you should pay attention to the dimensions of the mounting holes: they must fully correspond to the dimensions of the pipeline elements on which the sensor is planned to be installed.
Connecting and adjusting the sensor
The efficiency of the sensor that controls the flow of water and controls the operation of pumping equipment largely depends on the correct installation of this device. It should be borne in mind that such a sensor, regardless of the type and purpose of the pipeline, can only be mounted on horizontal sections. In this case, it is necessary to control that the sensor membrane is located strictly in a vertical position.
When installing a liquid flow sensor, it is connected to the drain part of the pipeline using a threaded coupling. At the same time, the distance at which such a device should be located from the pipe itself cannot be less than 55 mm.
On the body of factory water flow sensors there is always an arrow that indicates in which direction the liquid should move through them. When installing the sensor on the pipeline, it is necessary to ensure that this arrow coincides with the direction of water movement. In the event that the sensor is installed in a system through which a heavily contaminated liquid is transported, filters must be placed in front of it for the correct operation of such a device.
Despite the fact that fluid flow sensors are supplied from manufacturing plants with already adjusted parameters, self-adjustment have to be done periodically. For this, special bolts are provided in the design of the sensors. With the help of the latter, the degree of compression of the springs is increased or decreased, setting the level of pressure at which this device will operate.
So, to adjust the water flow sensor with your own hands, you must perform the following steps:
- drain the water from the pipeline system and make sure that the pressure has taken a zero value;
- turning on the pump, start filling the system with water;
- when the pump is turned off, which will occur on the signal of the sensor, fix the value of the liquid pressure;
- again draining the liquid from the system, fix the value of the pressure of its flow, at which the pump will turn on;
- after removing the sensor cover and using a special bolt, adjust the compression ratio of the large-diameter spring (this way you set the minimum pressure level at which the device will operate and the pump will turn on; it should be borne in mind that compression of such a spring increases the pressure level, and weakening reduces it);
- refilling the system with water and starting to drain it, check if the sensor is adjusted correctly and if it turns off the pump at the required pressure level (if the device is not adjusted correctly, the entire procedure described above should be repeated);
- by changing the compression ratio of a spring of small diameter, set the level of maximum pressure at which the pump will turn off (the difference between the sensor thresholds increases when such a spring is compressed and decreases when it is weakened);
- after adjusting the compression ratio of the small diameter spring, check the correctness of this procedure by starting to fill the system with water and fixing the pressure value at which the pump will turn off (if such an adjustment is not made correctly, it should also be repeated until the desired result is achieved).
In order for the pipeline system to function normally, experts recommend at least once a year to check the water flow sensors and, if necessary, adjust their operating parameters.
