Patent ID: 8936042
Filing Date: 2015-01-20
Classification: B24C,F16K,Y10T

Abstract:
1. A pneumatically controlled safety shut-off system capable of being controlled by either an electric dead man's switch or a pneumatic dead man's switch, comprising: a relay valve comprising a spool, a pressurized gas port, a vent port, a control circuit inlet/outlet, and pneumatic dead man's port, wherein the spool is biased toward a venting position wherein the control circuit inlet/outlet in fluid communication with the vent port; the relay valve further comprises a electrically operated solenoid valve; wherein the solenoid valve in its operating position provides fluid communication between the pressurized gas port and a spool chamber in the relay valve and at the same time blocks the pneumatic dead man's port, and the solenoid valve in its venting position provides fluid communication between the pneumatic dead man's port and the spool chamber.