TYPES OF VALVES DOE-HDBK-1018/2-93 Valves TYPES OF VALVES Due to the various environments, system fluids, and system conditions in which flow must be controlled, a large number of valve designs have been developed. A basic understanding of the differences between the various types of valves, and how these differences affect valve function, will help ensure the proper application of  each valve  type  during design  and  the proper  use of  each  valve type  during operation. EO  1.4 Given  a  drawing  of  a  valve,  IDENTIFY  each  of  the  following types of  valves: a. Globe b. Gate c. Plug d. Ball e. Needle f. Butterfly g. Diaphragm h. Pinch i. Check j. Safety/relief k. Reducing EO  1.5 DESCRIBE  the  application  of  the  following  types of  valves: a. Globe b. Gate c. Plug d. Ball e. Needle f. Butterfly g. Diaphragm h. Pinch i. Check j. Safety/relief k. Reducing Gate  Valves A  gate  valve  is  a  linear  motion  valve  used  to  start  or  stop  fluid  flow;  however,  it  does  not regulate or throttle flow.   The name gate is derived from the appearance of the disk in the flow stream.   Figure 4 illustrates a gate valve. The disk of a gate valve is completely removed from the flow stream when the valve is fully open. This characteristic offers virtually no resistance to flow when the valve is open.   Hence, there is little pressure drop across an open gate valve. When  the  valve  is  fully  closed,  a  disk-to-seal  ring  contact  surface  exists  for  360°,  and  good sealing is provided.   With the proper mating of a disk to the seal ring, very little or no leakage occurs across the disk when the gate valve is closed. ME-04 Rev. 0 Page 8