Pressure switch with changeover contact for high viscosity fluids

Range of adjustment between 1 and 100 bar

Pressure sensors and pressure switches with open flush diaphragms suitable for use with highly viscous media such as refrigerants, plastics, paper pulp, bitumen, sewage, paint and adhesives are an important part of the large Pewatron portfolio within pressure sensing and pressure switching. These high viscosity fluid pressure sensors/switches can be cleaned if there is a build up of residue around the process connection because all surfaces in contact with the viscous fluid are accessible. In this newsletter the focus is on the 603 pressure switch family with a changeover contact.

The changeover contact is an important feature of the 603 pressure switch, because it enables a simple alarm configuration for the pressurized system. When everything works according to specification, the primary electrical contact is on and can for instance be connected to a central controling unit. If a failure occur, for instance a pump failure or a pressure clog-up, the primary electrical contact is shifted to off (broken), and the secondary electrical contact is shifted to on. The secondary electrical signal can thus be used to signal an error state in the application/controller unit. The maximum switching frequency between the primary electrical contact and the secondary electrical contact is 200/min and the pressure hysteresis between the on and off state is ~20%.

The 603 pressure switch family consists of four pressure set ranges (1-10 bar, 2-20 bar, 5-50 bar and 10-100 bar). In each pressure set range the exact set pressure can be defined with an accuracy of 2-5% of the set point and dependent of the set point pressure. For 603 pressure switches with pressure set ranges 1-10 bar and 2-20 bar, the overpressure safety is 100 bar. For 603 pressure switches with pressure settings 5-50 bar and 10-100 bar, the overpressure safety is 300 bar.

The 603 pressure switch comes standard with a corrosion-resistant 1.4305 stainless steel housing, but can also be delivered in an acid resistant 1.4571 stainless steel housing variant for more critical applications. The process mounting thread is G ¾“ and the housing, thread and flush diaphragm construction has IP65 protection garantueed. Another important feature of the pressure switch is the ability of the switch to work in a broad range of temperatures from -20°C to 80°C.

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