lime delay valves.

lime delay valves

Pneumatic time delay valves (Figure 4.28) are used to delay opera­tions where time-based sequences are required. Figure 4.28a shows construction of a typical valve. This is similar in construction to a 3/2 way pilot-operated valve, but the space above the main valve is comparatively large and pilot air is only allowed in via a flow­ reducing needle valve. There is thus a time delay between applica­tion of pilot pressure to port Z and the valve operation, as shown by the timing diagram in Figure 4.28b. The time delay is adjusted by the needle valve setting.

The built-in check valve causes the reservoir space above the valve to vent quickly when pressure at Z is removed to give no delay off.

The valve shown in Figure 4.28 is a normally-closed delay-on valve. Many other time delay valves (delay-off, delay on/off, nor­mally-open) can be obtained. All use the basic principle of the air reservoir and needle valve.

The symbol of a normally-dosed time delay valve is shown in Figure 4.28c.

Control valves-0110

Related posts:

Case studies:VSD in a wastewater pumping scheme
Motors:Alternative electrical designs of motors
Compressed Air Transmission and Treatment:Hollow fibre filter
Optimizing and up-rating of existing systems:Optimizing conveying conditions.
Conveying characteristics:Energy considerations and The influence of conveying air velocity.
HYDRAULIC FLUIDS:PURPOSE OF THE HYDRAULIC FLUID
Hydraulic fluids:Characteristics of hydraulic fluids
Hydraulic cylinders:Cylinder mountings.
Hydraulic pumps:Vane pumps.
Air compressors, air treatment and pressure regulation.
Fundamental Principles:temperature measurement
PROPERTIES OF PURE SUBSTANCES:INTERNAL ENERGY, ENTHALPY, AND SPECIFIC HEATS OF SOLIDS AND LIQUIDS
THE SECOND LA W OF THERMODYNAMICS:THE CARNOT HEAT ENGINE
SUMMARY OF ENTROPY
GAS MIXTURES AND PSYCHROMETRICS:THE PSYCHROMETRIC CHART

Leave a comment

Your email address will not be published. Required fields are marked *