24. March 2020

Application of PM and ICS valve

Use of PM and ICS valves in industrial refrigeration systems

Differential pressure regulator

In addition to the receiver pressure control, there is another application for the control of the differential pressure. This applies to systems with hot gas defrosting, since the hot gas has to flow through the evaporator in the direction of the liquid line when defrosting. It should be possible to switch off this artificial differential pressure in operating phases without defrosting. In this case, it is advisable to use an "ICS" (or "PM") main valve with differential pressure pilot attachment "CVPP", as already mentioned. In order to switch off the differential pressure control, which is not required in collector control mode, an additional pilot is required: an EVM solenoid valve for direct mounting on "ICS" (or "PM").

If the two pilot valves "CVPP" (do not forget the branch line to the main line in the flow direction after the valve) and "EVM" are mounted in parallel on an "ICS" for a maximum of three pilot valves, the differential pressure function of the "CVPP" is active when the "EVM" is closed . When the "EVM" is open, there is no (increased) differential pressure. To control a main valve "ICS" with "CVPP" and "EVM", the solenoid valve "EVM" must be closed also normally open. Thus, for example, a normally closed "EVM" ("NC") would be closed when the coil was not energized. The differential pressure can then be set directly while the system is running,

As a measuring point in the direction of flow in front of the valve, the compressor pressure connection, or better still, the side pressure gauge connection on the "ICS" valve (always valve inlet pressure) can be used. After the valve, a measuring point on the condenser or collector or a corresponding T-nipple can be used the branch line to the "CVPP".

 

Fig. 1: Defrosting function Heading 1.01 Connection from the circulating canal Heading 1.02 Circumferential canal !!! The pressure from p1 (evaporator) is fed through this channel to connection P and to the pressure gauge connection. Heading 1.03 CVP (0-7 bar) connection opens when the defrost pressure rises to 5.5 bar in the evaporator and releases the pressure on the piston. Fig. 2: OPEN / CLOSE function Heading 1.05 The hot gas from the external connection presses the main piston and forcibly opens the main valve. external HG connection IN The solenoid valve EVM is located in connection SIl and opens or closes the path from SI (HG connection). So open / close function with HG support. Heading 1.06 By screwing in the ext. The channel to p1 is then closed. Heading 1.07 p1 is the pressure in the evaporator.

Main application in valve stations in the return line

Explanation of the connections and ducts in the PM and ICS main valve The paths for PM and the new ICS are identical

With ICS valves, the head module with the pilot valves can be rotated by 90 °. The function is retained.

 

 

 

 

 
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