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Pressure Switch  836T 

– Allen Bradley 

 

The lever assembly also includes a virtually friction-free over-center toggle arrangement, providing 

positive snap action to the contact block for long contact life. As pressure falls, force on the 

differential spring increases and contacts return to their normal state — this is referred to as reset 

setting. Varying the force of the main spring (by turning the operating range adjustment screw)  

 

determines when the contacts will trip. Varying the force of the differential spring (by turning the 

differential adjustment screw) determines when the contacts will reset. Setting trip and reset values 

determines the operating parameters of the application.

 

 

Figure 2 

Basic Mechanical Structure

 

 

 

 

 

Summary of Contents for 836T

Page 1: ...tween trip and reset Max occasional surge pressure Maximum surge pressure that can be applied to the actuator Surges or transients can occur during start up and shut down of a machine or system Expressed in milliseconds complex electronic instrumentation is required to measure the varying amplitude frequency and duration of this wave form Extreme surges that occur approximately 8 times in a 24 hou...

Page 2: ...and 3 8 in N P T female pipe threads SAE 7 16 and SAE 9 16 O ring boss seals are also available piston versions only Contact configuration Bulletin 836T controls are available with either a 2 circuit or 4 circuit contact block See Contacts Style D Style D pressure difference controls adjustable system difference range The adjustable operating range for a pressure difference control System differen...

Page 3: ...s are designed to open or close electrical circuits in response to changes in pneumatic air or gas or hydraulic oil or non corrosive liquids pressure Piston controls are not intended for use with air or water Figure 2 shows the basic operating mechanism Pressure is applied to the actuator which can be either a bellows or piston type As pressure rises the actuator exerts force on the main spring Wh...

Page 4: ...ses and contacts return to their normal state this is referred to as reset setting Varying the force of the main spring by turning the operating range adjustment screw determines when the contacts will trip Varying the force of the differential spring by turning the differential adjustment screw determines when the contacts will reset Setting trip and reset values determines the operating paramete...

Page 5: ...Figure 3 shows a typical control application Here pressure is controlled within predetermined high and low values Figure 4 shows a typical monitoring application Here pressure is monitored between a high and low value signaling when a preset limit has been exceeded Figure 3 Typical Control Application Figure 4 Typical Monitoring Application ...

Page 6: ...ening the lock nut the trip setting is set by turning the operating range adjustment screw counterclockwise to lower the trip setting or clockwise to raise the trip setting The approximate trip setting is shown on the indicating scale When the proper setting is reached simply tighten the lock nut Note Turning the operating range adjustment screw will cause both the trip and reset settings to chang...

Page 7: ...tment for pressure controls Mounting without Removing Cover Bulletin 836T controls can be mounted without removing the front cover This helps prevent foreign materials from entering the opened enclosure during the interval between mounting and wiring of the control ...

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