To provide for intelligent and safe operation of a boiler, a full complement of gauges and safety devices should be provided. These include: ● Water gauge (water level indicator) ● Pressure gauges. ● Safety valves: ● Dead weight safety valve: ● Spring loaded safety valve ● Lever safety valve ● High steam low water safety valve ● Fusible plug ● Feed check valve ● Stop…
The function of the fusible plug is to put-off the fire in the furnace of the boiler when the water level falls below an unsafe level and thus avoid the explosion which may take place due to overhearing of the tubes and the shell. Description of fusible plug: It consists of a hollow gun metal…
This valve has a combined safety arrangement against a) high steam pressure in the boiler and b) low water level in the boiler. A commonly used high steam low water safety valve consists of two valves, namely valve ‘U’ and valve ‘V’ as shown in Fig. 29.4 (a). Under normal condition, the valve ‘U’ rests…
The advantage of level safety valve over the dead weight safety valve is that the heavy dead weight is replaced by a lever with a smaller weight. Description of Lever safety valve: It consists of a valve resting over a gun metal seat. The valve seat is fixed on a mounting block, fitted over the…
Description of spring loaded safety valve: It is loaded with a spring instead of weights. Hence it is called spring loaded safety valve. It consists of a cast iron body having two branch pipes P1 and P2. Two separate valves are placed over the valve seatings, which are fixed to the top of the branch pipes….
Safety valves are devices used to maintain a constant safe pressure inside the boiler. When the pressure inside the boiler increases, the excess steam will escape to the atmosphere through the valve automatically. Generally, a boiler is provided with two safety valves. There are four different types of safety valves, viz., 1. Dead weight safety valves 2. Lever…
Water gauge indicates the water level inside the boiler and is hence called as water level indicator. Usually two water gauges are fitted in front of boiler. Description of water gauge: It consists of a glass tube, two gun metal tubes and three cocks. The steam cock C1 is provided on the gun metal…
Principle of Bourdon tube pressure gauge: when an elastic transducer ( bourdon tube in this case ) is subjected to a pressure, it defects. This deflection is proportional to the applied pressure when calibrated. Description of Bourdon tube Pressure Gauge: The main parts of this instruments are as follows: An elastic transducer, that is bourdon tube which is…
A pressure gauge is used to indicate the steam pressure of the boiler. It is also called as steam gauge. It is usually mounted in the front top of the steam drum. Figure shows a commonly used pressure gauge known as bourdon type. It consists of an elastic metallic bourdon spring tube S of elliptical…
The Dead Weight safety valve consists of a valve V which is made of gun metal to prevent rusting. It rests on the gun metal seat S and is fixed to the top of a vertical steam pipe P. The pipe has a flange F at the bottom for fixing at the top of the boiler shell. A weight carrier C is…