A pressure switch is equipment that is used to maintain specified pressure indicators on pumping equipment and in the line to which it is connected. What is a pressure switch for a pump, how to choose, install it? You can learn the answers to these questions from this article.
The design provides for the presence of sensors and controllers acting as sensitive elements. They measure the readings of the controlled parameter, after which they are converted into a form convenient for processing and transmitted to the relay. The relay, on the basis of this information, fulfills the programmed operations and restores the regular operation of the system.
Appointment
The water pressure switch for the pump (the connection diagram is presented below) is used to automate the procedure for saving the set parameters. What makes this device popular in all systems that provide for the management of processes associated with regulation in closed-loop indicator systems.
Classification
To date, the pressure switch is classified by the following indicators:
- Limit levels of measurement and control.
- The presence of additional contacts.
- Installation method.
- Degree of protection.
- Type and level of input signal.
- Type of power (external or autonomous).
Design features
The water pressure switch for the pump (the connection diagram is given below) is an electronic-mechanical equipment that shuts down and starts the pump unit at certain pressure values in the water supply network.
Devices manufactured by various manufacturers are structurally similar, the differences are only in minor details. Switching off and supplying power to the pumping unit is carried out by opening and closing the contact group - the main element of the relay. The equipment also includes two springs and a piston with a membrane.
After connecting to a special adapter of the station, the liquid pressure begins to exert an effect on the membrane, which, in turn, acts on the piston, which is connected to the contact group.
A large spring acts on the contact group from the opposite side, the compression of which is regulated by the corresponding nut. If the pressure drops due to the intake of water in the water supply system, the spring overcomes the effect on the piston side and the contact group closes by supplying power to the pump.
With increasing pressure in the pipeline, the piston will gradually displace the platform with the contacts, overcoming the resistance of the spring. However, the contacts do not immediately open, this only occurs as a result of movement by a certain distance, depending on the compression ratio of the small spring. Like a large spring, it is seated on a rod with a nut. As a result of opening the contacts, the pump unit is switched off.
Station principle
The water supply system in automatic mode delivers water to the tap under a certain pressure. The design of the station includes: a hydraulic accumulator, a pump, as well as a water pressure switch for the pump. The connection scheme involves the injection of fluid, which moves through the pipeline and goes into the accumulator, which is a kind of reservoir for the accumulation of fluid.
A membrane is located inside the accumulator, which compresses the air when it enters the fluid and increases in size. Then, when the tap is opened, water with a certain pressure begins to flow out of it, when it is closed, the movement of water stops.
At this point, the pressure becomes less than the set parameter, and the relay automatically activates the pump and the water again begins to flow into the tank. It arrives until the filling limiter trips and the pump stops using a relay.
Water pressure switch for pump: wiring diagram, principle of operation
The relay is a block with springs that are responsible for the dimensions of the maximum and minimum values of the fluid pressure. The springs are adjusted using special nuts.
The force of water pressure is directed to the membrane, and when it drops to the minimum value, the spring is weakened. When maximum pressure is reached, the membrane overcomes the resistance of the spring. Such membrane behavior causes either water on or off. That is, as a result of the action of the membrane on the spring, the contacts located under the housing cover are closed or opened.
As soon as the liquid level indicator reaches the minimum value, the electric circuit closes, supplies voltage to the pump, which starts to work.
Pumping equipment pumps water to the maximum level, after which the electric circuit closes, the voltage supply is completed, and the unit stops its operation.
Connection
Consider how to connect a pressure switch (see wiring diagrams below). These units have a non-standard input for connecting water. A household type relay, as a rule, has a four-inch input, while professional devices can be equipped with a larger input. For this reason, first of all, it is advisable to take care of the adapter.
Until a certain time, in the manufacture of pumping equipment, a standard part was used, popularly called the "herringbone". This adapter is a brass piece of pipe with a size of 100-120 mm and a diameter of 25 mm. One end is connected to the pump inlet. Outlets at the adapter are taps for connecting a water line, pressure switch and other equipment.
Currently, everything looks a little more complicated. With modern pumping units, relays are screwed directly into the equipment, or into places that at first glance are least suitable for this.
First of all, the pump is connected to a water source, after - to the power supply. Adjustment and adjustment is the final, third stage of work.
Need adjustment
Adjustment of the pressure switch for the pump (how to configure it will be discussed below) may be required for the following reasons:
- If for any reason factory settings are not satisfied.
- If the pump station is assembled at the installation site.
DIY adjustment
If for some reason the factory settings of the pumping station did not suit you , then the connection and adjustment of the water pressure switch are carried out independently. This will require a screwdriver or wrench. You will also need a key for tightening (loosening) the regulator nuts. Do not forget that in case of failure of the constituent parts of the station, the product loses its warranty. If the result of the violation was an incorrect connection diagram of the submersible pump, the connection as a whole was not made correctly - all this is not a valid reason for the manufacturer.
Setting should start by disconnecting from the voltage relay. After that, the cover that closes the relay is removed, and adjustment is carried out at will, for example, to increase pressure, measure or lower the response range.
Decrease or increase in pressure
Based on the foregoing, in order to reduce or increase the pressure without changing the range at which the relay operates, it is only necessary to tighten or unscrew the nut on the large regulator.
Response Range Changes
If, for example, you are satisfied with the lower threshold of operation, and you only need to increase or decrease the upper threshold, then a smaller regulator is used.
In the process of tightening the nut of this regulator, the upper threshold will increase to the right, without changing the lower one. When weakening, the process will occur exactly the opposite, that is, between them the difference will increase or decrease.
After adjustment, the voltage is turned on, the moment when the pump shuts off (upper pressure) is noted on the pressure gauge.
It so happens that the value of the moment of switching on and the response range are not suitable, then in this case the adjustment must be done with a large regulator, and then with a smaller one, monitoring the process by a pressure gauge.
Pressure switch for water pump: connection, price, reviews
According to consumer reviews, today the Danfoss relay is more popular, its pressure range is 0.2-8 bar. The cost of such equipment is about 3,000 rubles. A device from the German manufacturer Grundfos with similar characteristics costs already 4,500 rubles. Italian equipment Italtecnica with standard settings will cost about 500 rubles.
Domestic devices of the Gileks company are almost identical to Italian ones, but their cost is about 300 rubles. Thus, domestic products are significantly lower in cost, and in terms of their characteristics, they are practically not inferior to Western models.
Experts recommend installing equipment from one manufacturer, that is, if you purchased a German pump, then the pressure switch should be from the same manufacturer.
Now you know what the pressure switch connection diagram looks like, how to connect it correctly, it will not cause you any special questions.