BOILER FEED REGULATOR AND CHECK VALVE

The boiler feed regulator and check valve shown in  is an improved form of the feed check valve described in art it is assembled from the parts shown in It con sists of two valves, viz, a regulator valve and a check valve, former mounted above the latter.

A cast iron elbow  is fitted with a valve seat  to mount the check valve and is bolted to the bottom of the valve body- part no.4 using eight bolts , washers  and nuts a moushroom type of check valve  rests on the check valve seat. The valve has a long stem and is guided well during its lift. The regulating valve seat  is fitted into the valve body . the regulating valve  which is connected to the valve spindle  by means of sleeve nut  the regulating valve has a long cylindrical projection below it to control the upward movement of the check valve. The valve spindle is coupled to the top spindle with help of a coupler a collar 1 and a taper split pin  this joint permits the rotation of the top spindle independent of the valve spindle. Therefore during the lift of the regulating valve the valve spindle will slide through the packing which greatly increases its life. The valve spindle projects uot through the cover  fixed to the body using eight bolts  washers and nuts  to prevent the leakage of the feed water between the valve spindle and the cover a gland  along with the gland ring is mounted on the cover so as to retain the packing in the stuffing box in the cover and connected to it by T-bolts  and nut  the to spindle is screwed through the bridge  which is supported by two collar stude  which are fixed to the cover. A hand wheel  is keyed to the top spindle by a key  and secured to it using  nut  and spring washer  a cover plate  is bolted to one of the discharge flanges depending on the location of the discharge pipe with respect to the valve position. The plug screw  is screwed at the bottom of the elbow. 

JUNCTION STOP VALVE:

A Junction stop valve regulates the flow of the fluid and diverts its direction of flow a well. The Junction stop valve is often mounted on the boiler to control the flow steam from it.

The function of the valve is as follows. The rotation of the hand wheel in the appropriate direction raises the screw spindle independent of both the top and the valve spindle which will leave a gap just above the collar of the top spindle. This will permit the instantaneous lift of the valve by the steam pressure which intern allows the flow of the steam.

Shows the details of the JUNCTION STOP VALVE. Assemble the parts and draw the following views of the assemble .

STOP VALVE:

The stop valve are used in pipe lines when quick control or sudden shutting off of the flow of the fluid is desired. The stop valves of several designs are in which the most common type of the stop valve used in water and steam pipe lines is dealt here.

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The stop valve shown in  is assembled from the parts shown in  the body  has two parallel flanges to facilitate its mounting in the pipe line. A valve seat part no 6 is fitted in the flow passage of the valve body. A lift type of valve  is connected to the lower end of the spindle using a collar  and a taper pin  the cover  which is secured to the body of the valve with using studs  and nuts a gland is mounted on the cover so as to retain the fiber packing stuffed into the stuffing box in the cover using two studs and nuts  the spindle is screwed into a bridge  supported at its ends by two collar stud  which are mounted on the cover. A hand wheel  is fitted at the top end of the spindle and secured to using a nut .

FEED CHECK VALVE:

The check valve is one of the improtant boiler mountings.It helps to regulate the supply of the feed water to boiler and thus enables to keep the water level constant. It is usually fitted in the feed pipe line close to the boiler sheell so as to lie just below the working water level. The feed water is pumped into the boiler through the feed check valve which pervents its blowing back due pressure in the boiler.

Shows the details of the FEED CHECK VALVE assemble the parts and draw the following views of the assembly .Shows one of the simple types of the feed check valves used in the boiler feed system. it is assembled from the parts shows in firers. 

FORCE PUMP:

A force pump is a single type of reciprocating pump suitable for handling water. Shows a force pump. Its components are shown.The pump barrel shown in  is provided with a flanged passage with its axis at right angles to the axis of the barrel at its lowed end. A neck bush is fitted into the barrel. A plunger passes through the neck bush. A clamp bolt is fastened to the bottom of the plunger by a castle nut  which is locked in position on the bolt by a split pin  the plunger in driven by the plunger rod – not shown in figure, fastened to the clamp bolt by a cotter pin – also not shown in figure. To prevent the leakage between the plunger and the neck bush, some kind of fiber packing  is stuffed into the annular space just above the neck bush and help pressed in position by the gland bush  which is fitted into the barrel-cover  fixed on the top of the barrel and secured to it by four bolts , four nuts and four nuts .  he pump barrel is connected to the valve chest  by bolting their flanges together using six bolts  six nuts  and lock nuts  the valve chest is provided with the suction and delivery passages fitted with the valve  the lower one suction valve and the upper one is the delivery valve. Both the valves are unidirectional. The suction valve fits into the valve seat  shown in the lifted position in the assembly drawing. The lift of the suction valve is controlled by the valve adjuster  held in position in the nut  fitted on the overhanging portion of the valve stopper cum cover  which is secured to the valve chest using eight studs washers  and nuts  the delivery valve is also fitted into the valve seat which is fitted into the delivery opening in the valve chest. the lift of the delivery valve is controlled by the valve adjuster fitted into the projecting webs on the underside of the air vessel  fitted on the top of the delivery side of the valve chest and secured to it by five cured to the valve chest using studs and nuts to close the opening.
 The action of the pump is as flows. When the plunger is lifted up by the plunger rod. Water rushes into the valve chest by lifting the suction valve due to the atmospheric pressure acting against the vacuum in the pump barrel. The draw of water into the barrel takes place continuously during up ward motion of the plunger. When the plunger is moved down by the plunger rod the water pressure increases which force the suction valve to close and the delivery valve to open. The water discharges through the delivery valve. The air vessel equalizes the flow of water to give uniform rate of discharge.

CYLINDER RELIEF VALVE:
The steam supplied from a boiler unless superheated will be wet steam. When the engine is working the water particles suspended in the wet steam and the water formed by condensation will be driven by the piston to the cylinder ends. This at the end of the stroke develops excessive on the cylinder cover which may blow off. To prevent this the cylinder relief valve are often fitted to the ends of the engine cylinder. The cylinder relief valve is a spring loaded valve which blows off the water accumulated at end of the cylinder and also the steam when the excess pressure is developed at the end of the stroke.

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 shows cylinder relief valve it is assembled from the parts shown in the body of the vale  is a right angle elbow. Awing type of valveis held down by the spring  the spring pressure can be adjusted by a screw  screwed at the top of the cover  which itself is screwed over the body, the lock nut  enables to lock the screw in any desired position. When the pressure in the engine cylinder increases the valve will be lifted by the excess pressure and the water and the steam will escape through the opening in the cover.

Safety valve:
Boilers are designed and tested to withstand a certain amount of pressure but in the interest of the safety of the boiler the actual working pressure will always be less than this pressure, to prevent the rising of the boiler pressure to unsafe limits which wold lead to the bursting of the boiler a safety device known as safety valve is mounted on the boiler. A safety valve releases the essentially consults of a lift type valve held closing an aperture which is exposed to steam pressure of the boiler by a mechanical force which exerts a pre-set pressure. When the boiler pressure exceeds the pre-set pressure the valve will be lifted by the steam pressure to release the excess steam to the atmosphere so as to reduce the pressure in the boiler to safe limits. The common type of safety valve employed in the boiler practice is dealt here. They are 1. Rams bottom safety valve, 2. Lever safety valve and 3. Dead-weight safety valve.

RAMS-BOTTOM SAFETY VALVE:

The rams bottom  safety valve is aspiring loaded type of safety valve . it usually employed in mobile boilers such as locomotive and marine boilers Shows a rams bottom safety valve. It is assembled from the parts shows in  the body is a u-shaped casting having two brunch pipes uniting at the bottom to from into a flanged opening. The top end of each of the branch pipes is screwed with a gun metal valve seat  two web type of gun metal valves are mounted over the valve seats a pivot  pivoted to the end of the lever valves. The other valve is held in position by a projected pivot extended from the lever. Both the valves are held down on the valve seats against the steam pressure by the pull of the spring  the top end of which is hooked to the shackle  which inurn is fitted to the main body using hexagonal nut  and  hexagonal lock nut two links are also connected to the lever and the shackle using two pins and two split pins  so as to permit the lift of the valves. these links prevent the lever and the valve from being blown away in the event of spring failure.  

DEAD-WEIGHT SAFETY VALVE:

 Is this type of the safety valve the blowing off pressure is set by the force exerted by the dead-weight. This safety valve is used only on low capacity stationary boiler.Shows an open type dead-weight safety valve. It is assembled from the parts shown in the valve support parts.The working of the safety valve is as flowos. When the pressure of the steam in the boiler is about to reach the blowing-off pressure. The valve will be lifted up which results in the escape of the surplus steam  through the ports provided in the sleeve of the weight carrier. The lift of the valve is retrained by three stopper screws. Since the centre of gravity of the weights is below the valve aperture t tends to produce steady action during the lift and fall of the valve.