Zero Velocity

Drawing Catalogue

The principle behind the design of zero velocity valves is to arrest the forward moving water column at zero movement i.e. when its velocity is zero and before any return velocity is established. The valve is developed to eliminate water hammer problems in pipe lines.

The valves fitted in a pipe line consist of an outer shell and an inner fixed dome leaving a streamlined annular chamber for water. A closing disc is mounted on center and a peripheral guide bar is held at the close position by one or more spiral compressed springs when there is no flow of water. One or more numbers (depends upon the size of valves) by pass arrangement connects the upstream and downstream water on disc. The springs are so designed that the disc remains in fully open position for velocity of water equal to 25% of the designed maximum velocity in the pipe line. In case of closure of pump disc starts closing the relation to decreasing the velocity becomes less than 25% of the maximum velocity, disc starts closing and fully closed when velocity drops near to zero. Thus upstream water column is prevented from creating water hammer wave.

By pass arrangement keeps pressure balance on both sides of disc. It also prevents creation of vacuum in downstream side.

The valves are generally supplied with barrel ends but can also be made flanged ends, if so desired.

High quality finish epoxy coating in the valves makes the zero velocity valve corrosion free for a long life, low maintenance and smooth trouble free operations.

The zero velocity valves are self actuation and does not required any add on actuating devices. The valve can be installed at remote locations.

DVPL Zero velocity valve prevents the positive surges by preventing the water column to return, which is achieved by special design of the valve sensitive to the velocity of water and doses by specially arrangement of springs, which the forward velocity reduces to zero.

This breaks the energy of the returning water column and controls the positive surges.

DVPL Zero velocity valve has four foot for safe handling during transit and for easy and fast installation for sizes 400mm and above.

ZERO VELOCITY VALVE ARE FEATURED WITH:-

• High quality leak proof sealing guaranteed against leakage problems.
• Heavy duty operation due to its robust construction feature.
• Smooth operation trouble free service.
• Long life.
• Versatile and can be used for all kind of mains.
• Easily installed.
• Low maintenance cost and cost effective then many salutations.
• No noise distortion in operation