MIL-DTL-23450 Valves, Expansion, Thermostatic, Refrigerant-12 \(R-12\) And Refrigerant-22 \(R-22\)This specification covers two types and two styles of thermostatic expansion valves for use with refrigerant 12 \(R-12\) and refrigerant 22 \(R-22\).

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MIL-DTL-23450D

3.4 Design. The thermostatic expansion valves shall be designed as specified herein and in

accordance with MS17982 for use with R-12 or R-22 as applicable (see 4.4.1). The maximum envelope

dimensions of the valve, and the type and size of inlet, outlet, and external equalizer connections shall be

as specified in MS17982. The valve inlet and outlet configuration shall be straight-through (style I) or

angle (style II) as specified in MS17982. Valves MS17982-1 and MS17982-2 shall have a removable

strainer provided at the inlet side of the valve.

3.4.1 Type I and II valves. The type I and II valves shall be designed to automatically control the flow

of refrigerant from the high-pressure side of the system to the low-pressure side of the system through a

pressure-controlled orifice in accordance with the load demands of the system at the evaporator. The

basic response of the valve shall be with respect to the superheat change of the gas in the suction line.

The valve shall provide means for external adjustment of the superheat setting.

3.4.1 Fabrication. Method of fabrication (welding, brazing, soldering, and scaling) shall be at the option

of the individual manufacturer.

3.5 Performance.

3.5.1 Capacity. The minimum capacities, in British Thermal Units per hour (Btuh) of the types I and II

valves shall be as specified in MS17982 when tested in accordance with 4.4.4.

3.5.2 Superheat setting (type I and II). Type I and II valves shall be tested for superheat setting in

4.4.5. The superheat setting shall be as specified in MS17982.

3.5.3 Superheat change (type I and II). Type I and II valves the superheat change induced by the seat

leakage test of 3.5.5 shall not exceed the value specified in MS17982.

3.5.4 Pressure limit (R-12 type I). MS17982-1 and MS17982-2 type I R-12 valves shall be set as

specified in MS17982. The valves shall throttle or stop the flow of refrigerant when the suction pressure

at the evaporator reaches the maximum pressure setting, and shall operate normally when the suction

pressure falls below the maximum pressure setting. The pressure setting of the valves shall be tested in

accordance with 4.4.6.

3.5.5 Valve seat leakage (types I and II). The valve seat for types I and II valves shall meet the

requirements of the test specified in 4.4.7.

3.6 Marking for identification. Valves shall be marked in accordance with commercial practice. In

addition, valves shall be marked to include the applicable part number as specified in MS17982.

3.6.1 Valve body flow indicator. The valve body shall have an arrow or other significant marking legibly

and permanently stamped or embossed showing the direction of refrigerant flow.

3.7 Finish. The valves shall have the manufacturer's standard commercial finish.

3.8 Workmanship. The finished thermostatic expansion valve shall not be fractured, split, punctured,

dented, or malformed. Soldering, when applicable, shall be complete, clean, and adherent and shall not

have any pinholes. Welding and brazing where applicable, shall be complete, uniform, and properly

fused, having no burn holes, slag, inclusion, scale or flux deposits, and shall not be cracked, fractured, or

undercut. The valve shall not have any sharp burrs, slivers, or splinters.