Vacuum breaker is a simple device that facilitates air movement into the steam piping system especially when vacuum is induced. The steam heating system produces a hammer like noise generally known as water hammer. This could be annoying to the ears. It includes conditions that could lead to damage in the traps, vents, piping and regulators. Vacuum breaker valve by Dual Valves helps in contained this condition. Find customized heating and cooling products for industrial processes at advantageengineering.com.
The water hammer can be divided into two types, one is the condensate accumulation and the other is cavitation. The former is water trapped in the horizontal steam piping. The velocity of the steam passing over the condensate leads to the ripple sound. In this case turbulence builds causing the formation of a solid mass filling up the pipe. This solid mass condensates at the speed of the steam and causes the hammer blow.
The cavitation is caused due to the steam bubble being pushed in the pipe that is filled with water. As the bubble losses heat it implodes as the water wall comes together creating a severe force. This can lead to crushing of float balls and can destroy thermostatic elements found in the steam traps. Cavitation is found in wet return lines and discharge piping of pump. A steam system that is regulated does not lead to water hammer.
A steam system promotes condensate drainage irrespective of the operating condition and help in reducing water hammer. Moreover it results in reduced temperature swings and safeguards from uneven temperature. Finally it cuts down on product waste. The heat transfer devices calls for vacuum breaker designated at the points recommended by the manufacturer. The location where the breaker is to be installed includes post control value, above the heat transfer device and steam trap inlet.
All the heat transfer parts whether shell and tube exchanger, air heating coil, plate and frame exchanger or any other device Without vacuum breaker the condensate will back up on the coil and will be visible on the glass. After the vacuum breaker is fixed the coil is free of condensate in all operation conditions. With this the life span of the equipment is extended.
The role of the heat trap is to completely drain the condensate and for this the steam trap should have an outlet tapping that drains into a vented condensate return unit due to gravity. The trap needs to be placed 15 inches below the heat exchanger outlet. Meanwhile the 15 inches trap inlet static head with offer ½ psig static inlet pressure when the shell steam pressure is about 0 psig. The size of the trap has to based on the differential pressure. Meanwhile the safety factor is calculated keeping the full load capacity. For heat exchanger the best option would be a thermostatic or a float trap. Meanwhile the thermostatic element will quickly remove the air from the heat transfer shell. The float element will lead to continuous drainage matching the system condensing rate.