Efficient KJS Bellow Sealed Valve Solutions for Leak Prevention
Leakage from the Valve gland or stuffing box is normally a concern for the maintenance or plant engineer.
This leakage means:
a) Loss of material
b) Pollution to the atmosphere
c) Dangerous for plant employees
Losses incurred due to this type of leakage are considerable.
Steam at 150 psi escapes through a gland with a clearance of 0.001 in. at a rate of 25 lb/hr.
This means a loss of $1.2/8-hr shift and $1,100/yr.
A tiny drop of 0.4 mm diameter/sec results in a waste of about 200 l/yr of costly oil or solvent.
Apart from this high cost of energy and material loss, the leakage also results in serious environmental, ecological and oftne hazardous pronlems. The leaking fluid can be corrosice, explosive or poisonous. In a any case, it has to be checked before it leaks.
In Bellow sealed valves , a bellows cartridge is welded to the valve bonnet and stem.
(additional to the existing conventional gland packing of the valve as a secondary protection of the valve’s steam leakage)
A bellow is a long accordion-like tube.
As the valve stem strokes, the bellows expands or compresses with the stroke movement.
There are no sliding or rotating seals through which process fluid can pass.
Features Of Bellow Sealed Valves
• Bellow Seal Valve comply with full condition at high temperature and high pressure.
• Bellow Seal prevents leakage of sensitive media which constitute high fire risk.
• The bellows are capable of withstanding many cycles
• Gland packed valves often demand continual maintenance – inaccessability creating particular difficulties.
• Best suited valve for all critical applications.
• Heat Transfer media: hot oil is commonly used in industries such as synthetic fibres / POY (Partially Oriented Yarn). However, there is always a risk of fire due to hot oil spillage on highly inflammable chemicals. Here, bellow seal Valves can stop the leakage.
• Vacuum / ultra high vacuum: some applications require a vacuum pump to continually extract air from a pipeline. Any conventional Valves installed on the pipeline can allow external air to enter the pipeline thorough the Valve stuffing box. Hence the bellow seal Valve is the only solution to prevent air from passing through the stuffing box.
• Highly hazardous fluids: for media such as chlorine (see Figure 2), hydrogen, ammonia and phosgene, the bellow seal Valve is an ideal design as leakage through the gland is totally eliminated.
• Nuclear plant, heavy water plant: in instances where radiation leakage is to be prevented at all times, the bellow seal Valve is the ultimate choice.
• Costly fluids: in some applications leaks need to be avoided simply because of the high cost of the fluid. Here, an economic assessment often favours the use of bellow seal Valves.
• Environmental standards: around the world, standards regarding emissions and the environment are getting more stringent day by day. It can therefore be difficult for companies to expand within existing premises. With the use of bellow seal Valves, expansion without additional environmental
damage is possible.