MARSH STEAM PUMP.
The Marsh Steam Pump is so constructed that the exhaust steam may be turned into the suction, thereby condensing its exhaust steam and returning it with its heat to the boiler, thus heating the feed water to a high degree.
The pump is automatically regulated and can never run too fast to take suction, or should the water supply give out when the throttle valve is wide open no injury can occur to the moving parts.
The steam valve, though nicely fitted, moves freely in the central bore of the steam chest, and has no mechanical connection with other moving parts of the pump, but is actuated to admit, cut off and release the steam by live steam currents which alternate with the reciprocation of the piston.
Each end of the valve is made to fit the enlarged bore of the steam chest, and it is due to these large valve heads, which present differential areas to the action of steam and the perfect freedom of the valve to move without hindrance from other mechanical arrangements or parts, that the flow of steam into the pump is automatically regulated.
MARSH PUMP.
Capacity 10 to 35 Horse-Power.
The steam valve does not require setting, as it has no dead center and will always start when steam is admitted.
The steam piston is double and each head is provided with a metal packing ring. The piston rod is made of Tobin bronze, the stuffing boxes and water piston are made of brass, and the water cylinder is brass lined. The water valves may be removed for inspection by simply taking off the air chamber.
View of Marsh Steam Pump, Showing Water Valves,
Steam Valves, Suction Chamber and Piston.
DIRECTIONS FOR SETTING UP
AND RUNNING.
Before connecting the steam pipes, blow out with steam pressure the chips and dirt in the steam pipes. Always use the union furnished with the pump. It has a gauze gasket in it to catch the dirt that may get into the valve. Before starting pump, open air cock in delivery pipe and turn exhaust lever back, away from the air chamber. Then open throttle valve wide and allow pump to exhaust into the air until it takes suction, when deflecting lever may be thrown forward toward air chamber and cold water in the pump will condense the exhaust and return it to the boiler.
If pump refuses to work, the difficulty is to be looked for in the valve chest. Do not take off the chest. The valve may be taken out and cleaned but never filed. The valve must be returned through same end as taken from. Before closing, be sure that the head is screwed tight on the valve, using the socket wrench furnished.
When the pump is stopped, pull the exhaust lever back, so the condensed steam from leak of throttle valve will not go into the pump. It is safer also in cold weather to take off head of water end. Slight but constant lubrication adds much to the regular working of the pump. Be sure there are no leaks in the suction pipe, and when water is raised more than 10 feet, a foot valve should be put in. Compress the packings on piston rod as little as possible and yet prevent the escape of steam. Before leaving the pump in cold weather, break the suction and allow it to run empty for a minute with all the cocks open, then be sure the throttle valve is closed tight. When necessary, pack the joints under the steam chest, side plate and air chamber with manilla paper or thin rubber.