An autonomous water supply system with water intake from a well or a well is an integral part of the modern life of people outside the city. Such a water supply system consists of a pump, a hydraulic accumulator, filters and consumers for various purposes. They are all connected by pipes. There is a small box in this system called a pressure switch. Its purpose is to regulate the water pressure in the water supply system.
How does a relay work
The pump runs as long as voltage is applied to it. The hydraulic accumulator accumulates water and distributes it under a certain pressure to consumers. Individually, these devices are just tools that work on their own. In order for them to work in the system, they must be constantly monitored. For example, turn on or off the pump if the water pressure drops or rises in the system, respectively.
The relay makes it possible to avoid these hassles, because everything will work in automatic mode. In this case, the relay also acts on other parameters of the water supply system:
- reduces the load on equipment that is part of the plumbing system;
- reduces wear and tear;
- increases the service life;
- keeps the water pressure inside the network at the same level.
The principle of operation of the relay is directly related to the operation of the accumulator. Inside the latter there is a membrane that fixes and regulates the pressure inside the water supply network. With a small amount of water inside the membrane, the pressure drops. The amount of water increases, the pressure rises.
Switching the pump on and off is taken over by the relay. As soon as the pressure inside the accumulator drops, the contacts close, through which the current moves to the electric motor of the pumping unit. When the pressure rises, the contacts open, and the pump also stops.
The design of all relays from different manufacturers is the same. They work on the same principle. The part is inexpensive, and purely constructive, it is simple.
Relay design features
The main element of the product is a steel plate that reacts to changes in pressure inside the hydraulic tank. It bends as the pressure rises, opening the contacts, and returns to its original position when the pressure drops. The electrical contacts are closed.
The so-called spring block is present in the design of the relay. It consists of two springs of different sizes. The big one is responsible for setting the low pressure - for turning the pump on and off. Small for the pressure difference - the interval during which the pump will operate. The first is responsible for containing the pressure of water. It can be adjusted with a nut located at the top. The second spring is adjusted in the same way.
The adjustment of the water pressure regulator for a borehole pump must be approached from the position of its correct installation. Therefore, experts recommend installing it next to the accumulator. At its outlet, pressure drops, turbulence of the water flow are leveled, this is especially noticeable when the pumping unit is turned on.
How to properly configure
- working pressure inside the hydraulic tank;
- the maximum and minimum pressure that a pump installed in an autonomous water supply network can create.
The relay is set at the factory to standard settings. The springs are clamped to a certain height. But, as practice shows, the set values often do not correspond to the technical parameters of the water supply system.
It is necessary to start the adjustment with a large spring. The optimal version of the water pressure within the network is 1.5 atm., This will be the starting point in regulation. Usually, the reconciliation is carried out using a pressure gauge, which is installed next to the accumulator. This is done like this:
- water is pumped into the hydraulic tank up to 1.5 atm .;
- the pump turns off;
- a large spring is pressed with a nut until the pump turns on automatically;
- this is the lower limit that the pumping unit will turn on.
Next, you need to adjust the small spring. It is pressed until the pump turns off. Typically, a manometer should indicate an indicator in the range of 2-2.5 atm. But here everything will depend on the needs of the water supply system, the volume of the accumulator.
An important point on which the correct operation of the entire water supply network depends: the pressure in it must always be higher than the same characteristic inside the hydraulic tank by 0.2 atm. Otherwise, the service life of the rubber membrane will be reduced.
Thus, as soon as the pressure inside the accumulator reaches the lower limit, the relay will close the contacts. The pump will turn on and begin to drive water into the pear-shaped membrane. It will expand until the air pressure inside the hydraulic tank reaches a critical value (up to 2-2.5 atm.). The device turns off and stops pumping water.
When one of the consumers opens, water from the membrane will begin to flow into the water supply system. The air pressure inside the tank will begin to drop sharply. Having reached the critical value (1.5 atm.), The reduced parameter will give an impetus to the alignment of the plate, and it will close the contacts, the pump will turn on.
Criterias of choice
Like all devices that open and close contacts, the relay has one characteristic that you need to pay attention to when buying a product. This is switching durability. Its unit of measurement is the number of on and off. The larger this parameter, the longer the device will serve. There is a fairly wide range here, depending on the brand and manufacturer. There are parts that have a switching wear resistance in the limit of 100,000, for others it reaches 5,000,000.
Also, when buying, the time during which the settings do not change is taken into account. Unfortunately, this parameter is not indicated in the product passport. You can find out during operation or consult with specialists who have long been engaged in the installation, repair and maintenance of autonomous water supply systems.
A pressure switch installed in an autonomous water supply system solves an important task: automatic switching on and off of the pumping station when the water pressure inside the network drops or normalizes. The device is an inexpensive product, small in size, so its installation is economically justified.
