INTRODUCTION:
The DSV-3 is a 3-way shut-off valve suitable for the SH series safety valves. In accordance with ANSI/ ASHRAE 15-2014 Safety Code for Mechanical Refrigeration, pressure vessels having 10 cubic feet or more of internal gross volume, shall be fitted with dual pressure-relief valves. This is typically accomplished using a pair of pressure-relief valves interconnected via a three-way dual shut-off valve. Even on smaller vessels this arrangement is often preferred because one valve remains operational, while the other is being replaced; thereby eliminating the need to remove refrigerant from the vessel. Manik Engineers can provide any or all the necessary components, in addition to the actual relief valves, as follows:
THREE-WAY DUAL SHUT-OFF VALVES
These rugged, forged steel bodied valves facilitate the parallel installation of pressure-relief valves. Because three-way valves will not isolate both pressure-relief valves simultaneously, they are considered the only acceptable type of shut-off valve for use with refrigerant relief piping. Their durable metal-to-metal seating and patented non-leak packing plus o-ring stem seal design combine for long, trouble-free service. Inlet and outlet connections are threaded female NPT all the same size. Shown below is a three-way dual shut-off valve in the stem out position (back-seated). The valve stem should be positioned so that only one pressure-relief valve is activated. While the valve can be either front-seated (front port is closed) or back-seated (back port is closed), the back-seated position (shown) is recommended for normal use because it takes pressure off the packing and reduces the possibility of packing leaks. THREE-WAY DUAL SHUT-OFF VALVES These rugged, forged steel bodied valves facilitate the parallel installation of pressure-relief valves. Because three-way valves will not isolate both pressure-relief valves simultaneously, they are considered the only acceptable type of shut-off valve for use with refrigerant relief piping. Their durable metal-to-metal seating and patented non-leak packing plus o-ring stem seal design combine for long, trouble-free service. Inlet and outlet connections are threaded female NPT all the same size. Shown below is a three-way dual shut-off valve in the stem out position (back-seated). The valve stem should be positioned so that only one pressure-relief valve is activated. While the valve can be either front-seated (front port is closed) or back-seated (back port is closed), the back-seated position (shown) is recommended for normal use because it takes pressure off the packing and reduces the possibility of packing leaks.