The pressure switch — small, but very important node of the pumping station. It differs from other elements in what demands additional control. This device controls condition of hydraulic tank and is responsible for inclusion and shutdown of the equipment therefore the correct adjustment of the pressure switch will provide long service of the pump.
Features and principle of operation of the device
The majority of models of the pressure switch have identical structure. In the plastic body the firm basis to which other parts are attached is concluded:
- metal platform;
- knot of electric contacts.
Also under plastic cover there are two springs of the big and small size. Under pressure of design the membrane pushes the piston which, in turn, lifts the platform squeezing big spring. That, resisting pressure, limits the movement of the piston. Gradually the platform under pressure of membrane rises, resting against small spring.
After overcoming level by the platform where this hinge is located, there is change of provision of contacts with disconnection of chain of power supply that leads to shutdown of the pump. After that water inflow in the device stops, and internal pressure gradually decreases while liquid in the hydroaccumulator is spent. As a result the platform falls lower than the level of the spring hinge, and electric contacts send signal already to inclusion of power supply. All cycle works in the automatic mode and the unlimited number of times can renew.
Indicators of operation of the equipment
Despite, apparently, full automation of process of work of hydraulic pump, functioning of the pressure switch depends on number of parameters and sizes. They have to be well clear to the user who will be able to make on the basis of them necessary manipulations. Here belong:
- pressure of inclusion and switching off;
- maximum pressure of shutdown;
- differential pressure.
Pressure of switching off or Rvykl is the pressure at which the pump resumes the work, that is carries out pumping of water into hydraulic tank. Usually lower pressure by default is 1.5 bars. As for pressure of inclusion or Rvkl, it is the second key indicator of functioning of the relay and usually there correspond 3 bars.
Differential pressure (ΔР) call difference between top and lower pressure. Most often this rate is 1.5 bars. To the peak or maximum allowed value of pressure there corresponds the size of the highest pressure in system. Normally it is about 5 bars or slightly less. In case of excess of this indicator the pumping equipment can fail at any time.
Measurement of pressure in the hydroaccumulator
Internal pressure plays key role in functioning of the hydroaccumulator. Its size in hydraulic tank constantly changes depending on amount of liquid and air in it. In turn water and air are located in the compartments which are not reported with each other separated by rubber pear or membrane. When water comes to tank, the rubber insert puts pressure upon it, moving on water supply. In the course of operation of the equipment in tank air is forced. In need of it it is possible to pit, having opened the automobile nipple on the body of the device and having stabilized thereby working pressure in capacity.
At connection of the relay to the pump it is necessary to measure current pressure in tank. By default in the new device it has to make 1.5 bars, however during its storage the part of air leaves, and pressure in capacity goes down. For exact measurement pressure in the hydroaccumulator it is possible to use the normal automobile manometer. It is the best of all if it is the model having scale with small step of gradation. If pressure is approximate to unit, it is necessary to change the pump on guarantee. However and the raised indicator is dangerous to work of all system though in this case it is enough to pit excess air by means of the valve.
Stage-by-stage setup of the relay
Before installation and connection of the pumping station and relay surely study technical documentation to the equipment. In it optimum and limit indicators of its work have to be specified. Remember that in case of achievement by key indicators of the device of maximum values the pump needs to be switched off manually and to adjust anew. Nevertheless, similar situations are extremely rare as the majority of superficial pumps simply have no sufficient power for achievement of limit indicators.
Setup of the relay has to be carried out before filling of the hydroaccumulator with liquid that indicators not only water pressures, but also air in capacity were reflected in the device. Adjust the device in the following order:
- Establish the working pressure of air, having slightly opened the valve.
- Turn on the pump.
- Fill tank with water, the optimum indicator of pressure of switching off will not be reached yet.
- Switch-off the pump.
- Rotate small nut until the pump is started automatically.
- Wait for filling of tank and automatic shutdown of the pump.
- Discover water and rotate big spring for inclusion pressure setting.
- Start the pump and fill with water hydraulic tank.
Adjust the provision of small spring. Pay attention to in what direction it is necessary to rotate adjusting springs: usually point the signs "+" and "-" to it. For inclusion pressure increment the big spring rotates clockwise, and for reduction - against hour.
If at the subsequent inclusions on the manometer the lower size of pressure is displayed, tuning is performed correctly. The difference between values of pressure of inclusion and switching off in 1-2 atm is considered also normal. In case of bigger error repeat the procedure of adjustment taking into account probable errors.
That the pumping station functioned in standard duty, it is necessary to measure pressure indicators in hydroaakumulyator every three months. At the expense of it stable operation of the equipment will be supported. At sharp change of key indicators it is possible to judge emergence of any failures which need to be eliminated.
If switching off pressure gradually increases during the operation of the pumping station, it can indicate contamination of the device, however hurry to change it is not necessary. Turn off fastening bolts on the relay body, remove membrane knot and wash out internal part of the device. Also purge all pumping equipment. If there is water leak directly from the relay body, most likely, the membrane is punched, and already then not to do without replacement of the device.
Serious breakages of the pressure switch can arise because of strongly polluted water pipes. Such situation is characteristic of old water supply systems from metal. For this reason it is better to clean water supply system before installation and setup of the pumping station. Besides, it is worth replacing metal pipes with plastic whenever possible completely.
Be careful during setup of the relay in relation to adjusting springs. Having squeezed too strongly, you risk to deform them that will inevitably lead to errors during device operating time. At the same time it is worth remembering that the pressure switch wears out over time. To prolong device life cycle, it is not necessary to use it on the maximum allowed settings. It is better to leave small power reserve, having avoided further breakages. If necessary to expose the maximum top pressure in system, for example, in five atmospheres, once initially the relay gets which maximum permissible value of work is not less than six atmospheres.