• gate valve
    Equipment- English

    Valve Types

          GENERAL In industrial piping, the control of flow is very important. Mechanical devices used for flow control are called valves. The principal functions of valves are: · Starting and Stopping Flow · Regulating or Throttling Flow · Preventing Back Flow · Regulating Pressure · Relieving Pressure Steel valves are classified by nominal pipe size (NPS) and by pressure-temperature service ratings. There are two service ratings; a Primary Rating and a Cold Working Pressure Rating: · The Primary Rating is a pressure rating established by standards and accepted practice at an elevated temperature. · The Cold Working Pressure Rating is the rating at ambient temperature (minus 20°F to 100°F). This rating is…