SOR Opposed Piston - Manual

Form 279 (02.13) ©SOR Inc. 1/12
Principles of Operation
Opposed Piston
Differential Pressure Switches
General Instructions
Registered Quality System to ISO 9001
A = Hi Pressure Piston
B = Lo Pressure Piston
Fh = Force, Hi Pressure
Fl = Force, Lo Pressure
Fs = Force, Range Spring
Fd = Force Resultant Differential (Hi–Lo)
Design and
specifications are
subject to change
without notice.
For latest revision, go to
www.sorinc.com
Table of Contents
Principles of Operation ....................... 1
Installation ...................................... 2
SIL Installation ................................. 2
Process Connection ........................... 3
Electrical Connection .......................... 3
Calibration ...................................... 3
Dimensions ..................................... 4
ATEX Marking Information ................... 10
Declaration of Conformity ................... 11
Basic construction is opposing diaphragm sealed pistons connected by a common shaft. Hi
side system pressure acts on Piston A to produce force Fh. It is counteracted by adjustable
range spring force Fs. Lo side system pressure acts on Piston B to produce force Fl. The
resultant force corresponds to the difference in pressure between the Hi and Lo system
pressures plus the force of the adjustable range spring, and moves the trip lever to actuate
and deactuate the SPDT electrical switching element.
NOTE: If you suspect that a product is defective, contact the factory or the
SOR Representative in your area for a return authorization number (RMA).
This product should only be installed by trained and competent personnel.
These instructions provide information for installation, electrical connection, process
connection and calibration of SOR
® Opposed Piston Differential Pressure Switches.