Introduction
Check valves allow the flow of refrigerant in one direction only by automatically closing when fluid attempts to flow in the opposite direction. The check valves are used generally used to protect compressors, pumps but also other apparatus from damage by liquid refrigerant.
Several constructions of check valves are available. Revalco chooses for a spring loaded valve construction of which, when opened, the valve body is completely outside the main stream.

Advantages:
1. Cage construction NB 100-150 (4"-6") prevents hammering or whistling as a result of too large/small valve
2. Standard supplied as a PN40 design. (on request PN52).
3. High Kv values resulting in low pressure drops.
4. Modular buid up stop-, regulating-, check- and stop check valves makes possible chang-over in existing installation.

Stop Check valve
The concept of a stop check valve is based on the combination of a spring loaded valve and hand operated stop valve.
The advantage of this two in one product lies in lower initial cost (you buy one stop check valve instead of a stop and a non return valve) and a reduction of installation time (less products means less welding).
However from servicing point of view the non return valve with a stop valve mounted seperately into the piping is still popular. Especially in larger dimensions.

Working media
Applicable for all common refrigerants such as NH3, R22, R134A, R404A, R502, R507, R404A, R407C, R410A, CO2 (R744) and non-corrosive gases/liquids. When using brines or refrigerants other then the above mentioned please consult your local Revalco representative.
Testing and Certification Every valve was tested in our factory according to EN12284 and designed according to CE PED 97/23/EC.

 
Survey of types
The valves can be supplied in angle and straight execution as Stop, Hand Expansion, Check and Stop-Check valve.

The European standard connections are according to EN 12284 :
NxxS-D = Check valve straight in NB xx (15,20,25,32,40,50,65,80,100,125,150)
NxxA-D = Check valve angle in NB xx (15,20,25,32,40,50,65,80,100,125,150)

The European standard connections are according to EN 12284 :
CxxS-D = Stop Check valve straight in NB xx (15,20,25,32,40,50,65,80,100,125,150)
CxxA-D = Stop Check valve angle in NB xx (15,20,25,32,40,50,65,80,100,125,150)

The valve are also available with connections according to ASME B16.9:
NxxS-A = Check valve straight in NB xx (1/2",3/4",1", 1 1/4", 1 1/2", 2", 2 1/2", 3", 4", 5", 6")
NxxA-A = Check valve angle in NB xx (1/2",3/4",1", 1 1/4", 1 1/2", 2", 2 1/2", 3", 4", 5", 6")

And in case of Stop Check valve:
CxxS-A = Stop Check valve straight in NB xx (1/2",3/4",1", 1 1/4", 1 1/2", 2", 2 1/2", 3", 4", 5", 6")
CxxA-A = Stop Check valve angle in NB xx (1/2",3/4",1", 1 1/4", 1 1/2", 2", 2 1/2", 3", 4", 5", 6")