Pneumatic 2-Position Pilot Operated Switching Relay

The Powers 243 SW Switching Relay is a two-position, pilot-operated auxiliary device used for switching a common part from one pneumatic circuit to another. A mounting bracket is provided for mounting on a vertical or horizontal surface. Application: There are applications that require a low differential switching relay that can be triggered by a gradual input signal. The following describes ways of connecting the 243-0001 switching relay to achieve this. The low differential is achieved by connecting the relay so its differential is the opening and closing of only one valve of the two-valve relay mechanism. A restrictor must be used in the output (“D” port) of the relay to make sure the relay valve can bleed the output signal down to approximately zero. Since a restrictor is used in the output of the relay, the switching relay becomes a low capacity device. Its air capacity is limited by the size of the restrictor. If a high capacity switching device is required, two switching relays can be used, one piloting the other. For a single switching relay configuration as shown in Figures 2 and 3, the switching differential is 0.5 to 1.0 psi (3.4 to 6.9 kPa). For a double switching relay configuration as shown in Figure 4, the switching differential is approximately 0.5 psi (3.4 kPa).