Time delay valve function

Time delay valve function need:

Time delay valve function : In certain  applications like machining or press operation it is necessary that certain operation be delayed by some fraction even after pressing valve. This objective is achieved by Time delay valve.

Time delay valve function working:

Time delay valve is a combination valve used to set the operation time as per the requirement. The time delay can be increased or decreased by adjusting the flow through the non-return flow control valve. The change invariably increases or decreases the time taken to fill and pilot actuates the direction control valve. Time delay valve is a combination of a pneumatically actuated 3/2 direction control valve, an air reservoir and a throttle relief valve. The time delay function is obtained by controlling the air flow rate to or from the reservoir by using the throttle valve. Adjustment of throttle valve permits fine control of time delay between minimum and maximum times. In pneumatic time delay valves, typical time delays in the range 5-30 seconds are possible.

The time delay can be extended with the addition of external reservoir. Time delay valve, NC type. The constructions of an on-delay timer (NC) type in the normal and actuated are shown in Figure It can be seen that 3/2 DCV operates in the on delay mode permanently. But, in some designs, the valve can be operated in the off-delay mode by connecting the check valve in reverse direction. Time delay valve  is shown in diagram below.

Time delay valve function diagram:

Pneumatic time delay valve is used when time based sequencing is required. Construction and symbol of valve is shown in figure below. It is simply a 3/2 direction control valve, which is impulse operated from one side. Time delaying is achieved by delaying the impulse actuation. The valve has an in-built air reservoir and in-built non-return flow control valve. When impulse is applied to port “Z” for valve actuation, the air passes through needle control valve, which controls the rate of flow, further the valve spool is not actuated until the air reservoir is filled completely and pressure is built-up. (This time difference between impulse application at “Z” and actual spool actuation is the “delay”, which is adjustable through needle valve). This valve is found applicable in time based sequencing, which is common industrial application, e.g. clamping, indexing, feed motions etc.

ALTERNATE DIAGRAM

====================================================

Time delay valve function additional information and Diagrams are given below.

YOUTUBE videos for Time delay valve function are given below

Time delay valve function is mainly used in pneumatic circuits. Main purpose of time delay valve function is to delay the next operation by certain amount of time which must be adjustable.