Alfa Laval® CPMI-2 Constant Pressure Modulating Inlet Valve

Alfa Laval Constant Pressure Modulating Inlet (CPMI) valves are sanitary constant-pressure valves for use in stainless steel pipe systems. The CPMI-2 valve maintains a constant pressure in the process line at the inlet side of the valve. Typical applications of this valve are after separators, heat exchangers, and as an overflow valve.

CPMI-2 is authorized to carry the 3-A symbol.


The CPMI-2 is remotely controlled by means of compressed air. The valve operates without a transmitter in the product line and requires only a pressure regulating valve for the compressed air and a pressure gauge in the product line.

A diaphragm/valve plug system reacts immediately to any alteration of the product pressure and changes position so that the preset pressure is maintained. CPMI-2 opens at increasing product pressure and vice versa.


The CPMI-2 consists of a valve body with valve seat, cover, a valve plug with a diaphragm unit, and a clamp. The diaphragm unit consists of a stainless steel disc—which is divided into sector—and flexible diaphragms that are placed on each side of the sectors. The cover and the valve body are clamped together. The valve body and the seat are welded together. The CPMI-2 meets 3-A standards.

Product Wetted Steel Parts316L
Other Steel Parts304
Lower DiaphragmPTFE covered EPDM rubber (standard)
Solid PTFE
Upper DiaphragmNitrile (NBR) standard
PTFE covered EPDM rubber
Solid PTFE
O-ringBuna (standard)
Fluorinated rubber (FPM) covered EPDM rubber
Finish32 Ra
Max Product Pressure145 psi
Min Product Pressure0 psi
Max Product Viscosity500 cps
Temperature Range14 – 203°F
Temperature Range with PTFE/EPDM Upper Diaphragm14 – 286°F (higher on request)
Air Pressure0 – 116 psi
Air ConnectionsR ¼ inch (BSP), internal thread

Pressure Drop/Capacity Diagrams


Dimensional Data

Cv 27Cv 8Cv 2/18
A1 (in)7.967.967.96
A2 (in)8.808.808.80
OD (in)2.312.312.31
ID (in)
t (in)0.0730.0730.073
E (in)
F (in)0.830.830.83
G (in)
H (in)
Tri-Clamp (in)0.960.960.96
Seat Diameter (in)1.911.411.41
Weight (lb)13.9913.9913.99


  • Plug size (Cv 23, Cv 8, Cv 10, or Cv 2/18)
  • Diaphragm type if not standard
  • Connections if not welding ends
  • Optional equipment if needed
  • Male parts or clamp liners in accordance with required standard
  • Pressure gauge 0 – 87 psi, 1½ inch
  • Pressure gauge 0 – 145 psi, 1½ inch
  • Air pressure regulating valve kit, 0 – 116 psi
  • Air throttling valve for adjustment of regulating speed for the CPM-2 valve
  • Booster for product pressure (product pressure = 1.8 x air pressure) exceeding the available air pressure
  • 3-A Sanitary Standard labelling on request

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