The 836-A4 pressure switch is a pressure control device that has been designed and manufactured by Allen-Bradley/Rockwell Automation. This specific part comes in the Allen-Bradley 836 Pressure Controls series of pressure sensors and controllers and it has been specifically designed as part of the Style A line of devices from the same series. This device works in different kinds of applications, especially in applications that use 2 different pressure values. These 2 pressure values come from the adjustable operating range which consists of the total span of values within the contacts where the contacts can be tripped and reset, and the adjustable differential range which is the difference between the trip and reset values. The adjustable operating range of this device is 16 inches in a vacuum and 375 PSI and the adjustable differential range is 8 to 95 PSI. 

The Allen-Bradley/Rockwell Automation 836-A4 pressure control device comes with an open kind of enclosure. This means that the device needs to be installed in a controlled environment that does not contain any hazardous materials. The device must not come into contact with liquids, vapors, gases, or moisture. The 2 independent pressure ranges (adjustable and differential) that operate in the Allen-Bradley/Rockwell Automation 836-A4 pressure control device are independently adjustable. This means that one of the values can be adjusted without affecting the other at all. The Allen-Bradley/Rockwell Automation 836-A4 pressure control device comes with standard copper alloy bellows and there is a wide range of accessories available in the 836 series to customize and improve the functioning of the device. The device is constructed to be frictionless to provide consistent operation regardless of the mounting angle.