Bladder Vessels

Bladder vessels alleviate negative pressures more effectively, than other forms of water hammer protection, and they can maintain a positive pressure in the pipe line at all stages following pump trip. This is accomplished by forcing water out of the vessel in to cavity, otherwise created following pump trip or flow stoppage at upstream end. The pre charged compressed air forces water from the BLADDER vessel in to the pipe line allowing the water column travelling up the pipe line to maintain its momentum. Friction and other head losses tend to reduce the water velocity and therefore subsequent oscillations.
The outflow from the Bladder Vessel is throttled to some extent . The outflow line consists of a non return valve. The return flow back in to Bladder vessel is appropriately throttled by the smaller size by pass line, which is provided with a control valve to adjust the throttling as per site requirement..In this manner continuous deceleration occurs by returning water column and y by air cushion.
The vessel is made out of high tensile carbon steel and is manufactured to rigid quality standards, as burst vessels containing air are more dangerous than those containing only liquid. The Bladder is sandwiched between top and bottom flanges as shown in the catalogue. Entrapped air from the Bladder will be removed by the air valve located at the top flange.
For special application where it is essential to allow air entry in to pipeline, we can provide arrangement, such that, the Bladder vessel forces water and then the air to contain oscillation of water columns.
The Bladder is coated with food grade Butyl rubber for normal water application. For sewage water we can supply Bladders coated with Nitrile rubber. For petroleum products the pre charge will be of Nitrogen and Bladder will be coated with nitrile rubber.
We can design optimum size of the Bladder vessel for a particular site by using simplified monographs presented by D.Stephenson, F.ASCE

Features :

• Available in 6,10,16,20 and 40 Bar working pressure
• Sizes from 8 to 10,000 liters
• Larger inlet size to water chamber as per water hammer analysis.
• Min vessel thickness in 6 mm, inclusive of 2 mm corrosion allowance.
• Water does not come in contact with vessel.
• Full size floating Bladder reinforced with high strength nylon, coated with food grade impervious Butyle rubber for long life.
• Drain arrangement to check pre charge air pressure
• Optional, protection cover, and base frame
• Indigenous tailor made designs. Easy availability of products and spares.

Air chambers (also called as Hydro pneumatic tanks) have proved to be most effective devices for control of water hammer, but are complicated and expensive. VAN make BLADDER VESSELS are improved air vessels, and eliminate all inconveniences of old Air vessel designs. Indigenously designed and produced, more than 1000 Bladder vessels are in use, since last 20 years.

Application :

• For water hammer control. The Bladder vessel inlet should be connected to main line as near to non return valve as possible. In any case the distance should not exceed 5*D (D=Dia of NRV)
• If the pipe lines are long, one can install NRV at intermediate location. Bladder vessel can be installed after the NRV.
• The return wave water column forces water through by pass line at very high velocity, and this velocity is killed instantly in the large volume of the Bladder vessel, and will release dissolved air. The air escapes through air valve provided on the top of the vessel
• The Bladder vessels control the pressure wave shocks created by sudden stoppage of pumps due to power failure, or sudden stoppage of valves, or sudden starting of pumps.
• Special design are available for sewage water containing fibrous material.
• Small units are available for arresting water hammer shocks and unwanted noise in Domestic pumping systems.