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Indicating type differential pressure switch with bellows element

Type: P640


Service intended


The P640 series are designed to measure differential pressure from 25 kPa to 2.0 MPa at static pressure 10 MPa and have electrical contact. A set of two stainless steel bellows mounted on a force balance allows direct reading of the actual differential pressure.


Nominal diameter


150 mm




±1.0 % of full scale
±1.5 % of full scale


Scale range (MPa, kPa, bar, mbar)


0 ~ 25 kPa to 0 ~ 0.25 MPa (P641 model)
0 ~ 0.4 MPa to 0 ~ 2.0 MPa (P642 model)


Static pressure


Max. 10 MPa


Working temperature


Ambient : -20 ~ 65 °C
Fluid : Max. 100 °C


Degree of protection




Temperature effect


Accuracy at temperature above and below the reference temperature (20 ℃) will be effected by approximately
±0.5 % per 10 ℃ of full scale



Standard features


Pressure connection


Stainless steel (316L SS), Monel and Hastelloy-C




Stainless steel (316L SS), Monel and Hastelloy-C


Case and cover


ALDC12.1, Black painted Screwed type




Safety glass




White aluminium with black graduations


Filling liquid for differential cell


Silicone oil




Black painted aluminium alloy (Zero adjustable)




Contact rating : AC 250 V 3 A / 125 V 5 A
DC 250 V 0.2 A / 125 V 0.4 A / 30 V 4 A
Dielectric strength : AC 500 V / MIN
Type : Micro contact, One and two SPDT


Conduit connection


¾" PF(F)


Process connection


¼" NPT(F)
½" NPT(F) at 3-way and 5-way manifold valve


Standard accessories


Mounting bracket for 2" pipe
mounting with silver gray finished steel




■ Remote seal - Not available with less than 40 kPa of differential pressure range
■ Mounting bracket with 316SS for 2" pipe
■ 3-way manifold valve (316SS, Monel)
■ 5-way manifold valve (316SS, Monel)



Download:  CATALOG 

Đồng hồ Công tắc áp suất chênh áp P641 P642

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