Automation unit for pump and pressure regulation. The automation unit (as the pressure switch is also called) is a kind of "brain" in the water supply system. In the usual scheme, the pump is controlled by commands from a pressure switch, which is installed on the pipeline.
Only two main parameters need to be set in the relay: the pressure when the pump is turned on, and the pressure at which the system is turned off.
This scheme is used for individual wells, and the automation in this case works together with a hydraulic accumulator (also a membrane tank), which is designed to maintain the required excess pressure, compensate for hydraulic shocks and as a small margin water.
It is very important to correctly configure the relay according to the characteristics of the pump and the volume of the membrane tank. To prevent the pump from being used too often, the pressure limit must be set in the middle working zone of the pump according to its characteristics. Typically, the value of the limits is determined in the range of 1.3-2.6 bar, while taking into account the maximum permissible number of pump starts over a certain period of time.
The electric pump is started by the automation unit every 23-27 seconds after connecting to the power supply (mains). Further starts occur when the starting pressure appears, which is available after opening the valve. Compared to the pressure-tank switch system, the stopping of the electric pump does not depend on the pressure in the system, but is determined by the decrease in flow to the minimum allowable value. As soon as the automation unit for the pump detects this condition, it stops the electric pump at intervals of 5-12 seconds, timing is aimed at reducing the frequency of the pump at low flow.
When you have chosen a convenient gauge location, plug the hole on the opposite side with an unsealed screw. Next, we install the automation tank strictly vertically at any point that is located between the pump feed and the point of draw-off (that is, the tap) so that the external thread is connected to the direction of water exit from the pump, and the outlet side hole corresponds to the direction of water in the pipeline. After all manipulations, make sure that the hydraulic connections are tight. When using an electric pump with a permissible pressure above 10 bar, install a pressure reducer at the inlet to the unit.
If you are going to use the automation unit with a single-phase or three-phase electric pump, the switching current of which will be higher than 10 Amperes, you should use an electromagnetic lowering device.
Important! The electrical cable must have a thermal resistance of at least 100 degrees.
According to the factory settings, the starting pressure will be triggered at a pressure of 1.5 atm. which is optimal for many use cases.
You can change this value with the adjusting screw located on the top of the block and labeled "+" and "-". After torsioning, close the relay cover and screw the screws back.
Attention! If the level of the filled water is lower than the level of the pump location, it is imperative to use the non-return valve located on the suction pipe.
In practice, many It is known that the main reason for pump failure is dry running, that is, without water. This pump operation is on a par with such a problem as a stable and high-quality supply of electricity, and is the most popular cause of device failure.
This applies to the borehole pump automation units, and to surface devices.
Pumps for household needs The main material of working diffusers and wheels is thermoplastic (wear-resistant and very durable plastic), which is high-tech and inexpensive. But with a "dry run", where there is no lubrication and heat removal in the form of water, the internal pumping parts begin to touch, and later this leads to the shaft jamming and combustion of the electric motor.
Usually, after this, the pump either does not supply water at all, or does not work in accordance with its passport characteristics.
Any manufacturer of the pump automation unit indicates in the instructions that it is prohibited to operate the device without water.
Potential hazardous locations for the pump, where such a problem may occur, are:
In this case, the pump is cut into the network pipeline and works to increase the pressure in the system. Since there is not enough pressure (especially in summer), this scheme is actively used, even at pumping stations. It is very often impossible to track when water is lost in the network.
It is inexpensive and reliable. It is often used when pumping water from a well or tank. There are two types of floats. One of them is often used for storage tanks that are filled with water - the contacts open and the pump stops filling the tank. But this float will save you only from overflow, and not from the combustion of the drive due to lack of water.
The second type of floats is used just for our problem. The float cable is connected to the break of one of the phases of the supply pump. When the liquid level falls below the selected level, the contacts open and the pump completely stops working. The cable from this float is fixed so that when the float is lowered to the water level, when the contacts are opened, a certain amount of water remains in the container.
This is a standard pressure switch with the function of opening the contacts when the pressure drops below the set level. The manufacturer sets this level at 0.4-0.7 bar and cannot be adjusted. The pressure can drop to this value only in one case - if there is no water in the pump.
The pump can be restarted, but only manually, and before this the cause of the dry running must be eliminated.
Reference: The use of a relay with a protection function is only available when the pump is operating in automatic mode in tandem with a diaphragm tank, otherwise the use of a relay becomes meaningless. Usually used in conjunction with a submersible pump, but sometimes applied in a surface pump or station.
It gives the command to turn on the pump at a standard pressure of 1.6 to 2.6 bar. The pump turns off after stopping the drawdown due to the lack of liquid flow through the relay. This protection is provided by an integrated flow sensor that records the flow rate.
Pump shutdown is performed with a short time delay, but this does not in any way affect the performance or reduce the service life. The main advantage of press control is its small size.
Pay attention! A non-return valve located between the automation unit and the electric pump, as well as after the automation, may cause the unit to malfunction. Correction of starting pressure must be carried out by a competent specialist, observing all safety standards. This operation is needed to change the initial pressure.
The shut-off pressure cannot be adjusted and is equal to the maximum pressure that is generated by the electric pump.
Posted By: Work Style |10, Nov 2020
Posted By: Work Style |09, Nov 2020
Posted By: Work Style |06, Nov 2020
Posted By: Work Style |09, Nov 2020
Posted By: Work Style |10, Nov 2020