US2032426A - Boiler feed regulator - Google Patents

Description

March 3, 1936. A. MAG'IS 2,032,426

BOILER FEED REGULATOR Filed July 16, 1952 IN V EN TOR.

A TTORNEY Patented Mar. 3, 1936 PATENT ()FFICE BOILER FEED REGULATOR Auguste Magis, Paris, France, assignor to The Superheater. Company, New York, N. Y.

Application July 16, 1932, Serial No. 623,001 In France November 13, 1931 1 Claim.

The present invention has for its object the provision of an automatic, simple, and efficient boiler feed regulator in which a float controls a servo-motor by means of a piston valve, the servo-motor being actuated by the feed water under pressure, the servo-motor opening or closing the connection to the boiler.

The regulator is characterized in the first place by the fact that the piston valve always has its ends under the pressure of the feed water so that it will always be balanced and secondly by the fact that the piston valve is located adjacent to the boiler and in direct communication with it. In this way all leakage of water which may occur can be directed into theboiler and such leakage is reduced to a minimum by the pressure of the boiler.

In addition, the two cylindrical chambers of the servo-motor are connected to the housing of the piston actuating the feed-water valve by appropriate channels so as to receive the motive fluid, which is the feed water, and so as to conduct it toward the boiler after having performed its work.

The use of a servo-motor makes it possible to act on the valve controlling the admission of the water to the boiler in a positive and efficient manner. The control of this servo-motor by the feed water under pressure rather than by an auxiliary fluid or by electricity makes its function certain and avoids duplication of the arrangements which would be necessary in case such auxiliary fluid or electric current failed.

The balancing of the piston of the servo-motor withdraws the movements of the float from the influence of the pressure of the feed water and the float is acted on only by the fluctuations of the boiler water level.

The fact that the leakage past the piston valve is carried to the boiler and reduced to the minimum by the pressure existing in the latter has the effect in the first place of avoiding loss of water and in the second place of avoiding pressure differences on the several faces of the piston valve which might interfere with its proper functioning. The combination whereby the servomotor is actuated by the feed water and any leakage of water is sent to the drum, results in a piston not being subjected to sudden temperature changes and makes it possible to take care of such expansion differences as actually do occur while yet keeping the movement of the parts as free as is required for their proper function- The description which follows and which (01. lei-101) 'makes reference to the accompanying drawing,

which should be taken as illustrative only, will make clear what the invention is and how it can becarried out.

The single figure of the drawing shows in vertical and more or less diagrammatic section the application to a boiler of an automatic feed regulator according to my invention.

In this figure, I represents the drum of a boiler in which the water level is to be maintained at a predetermined point or between predetermined limits. A chamber 2 communicating'with the water space 3 and the steam space 4of the drum I contains a float 5 fixed on a lever 6, this lever being pivoted at land being extended so as to produce with its farther end movements of the piston valve 9 which is reciprocable in the two cylindrical chambers l and H formed in the casting 21 secured to the outer end of chamber 2. These two chambers l0 and H are in ,alinement with each other and the pistons I2 and I3 of the piston valve 9 are fitted into them as snugly as consistent with free movement.

Feed water from the feed pump of course is delivered at the pressure equal to or in excess of that which prevails in the drum I, the conduit from the pump being designated by the numeral l4. From the feed line 14 there leads a branch l carrying the feed water under pressure by means of the two conduits l6 and I l to the opposite ends of the cylindrical cavities l0 and I! so that the end faces of the piston valve 9 are both constantly subject to the feed water pressure.

In the cylindrical cavities l0 and II there are arranged at suitable points the two ports I8 and H] which communicate respectively by means of the conduits and 2| with the two ends of the cylinder 22 of the servo-motor.

In this cylinder there is mounted reciprocably a piston 23 whose rod 24 carries on its opposite end a valve which may be either of a disk type or of a balanced type and which may wholly or partly open or close the communication between the conduit l4 and the conduit 26 leading to the boiler drum I.

The function of this arrangement is easy to follow. When, as is shown in the figure, the water level in the drum l and in the chamber 2 has reached the maximum allowable height the piston I2 of the piston valve has uncovered the port l8 thereby permitting feed water to pass from the conduit l4 through the conduits l5 and IS, the chamber In and the conduit 20 to exert pressure on the piston 23 in adirection to close the valve 25 and to direct to the boiler by means of the conduit 2| water which is in the cylinder 22 under piston 23; at the same time the piston H! of the piston valve 9 has opened port l9 to put it'into communication with the chamber 2 where the pressure exists equal to or lower than that of the feed water; there is therefore direct communication from the space below piston 23 and the chamber 2 and the boiler and valve 25 can close. The delivery of feed water to the drum I to the conduit 26 is therefore shut ofi.

When the water level falls to the predetermined lowest permissible point, the reverse process occurs and feed water is again admitted to the drum l.

The process which has just been described assumes that the various phases of this action follow each other almost instantaneously, an assumption which makes it easy to follow the manner in which the invention operates. In reality, however, the phases follow each other only after certain longer intermissions and the action of the float and of the piston valve 9 will usually keep the valve 25 in some intermediate position which will vary with the demand on the boiler, the admission of the feed water thus being more or less throttled according to the requirement in the drum l. 7

An examination of the drawing will show that all water escaping from chambers I0 and II by leakage around the piston valve 9 will go to the chamber 2 and thence to the drum I.

Since the difference in pressure between the feed line and the chamber 2 will never be large as 7 compared with the total boiler pressure, these space where the pressure approaches that of the atmosphere.

Similarly, all water which escapes from the 7 cylinder of the servo-motor 22 after having performed its work there, flows to the chamber 2 and the boiler. As for possible leakages around the stem 24, these return to the conduit [4 if the valve 25 is closed and go directly to the boiler when it is open.

It follows that there .can be no loss of water; that without any ensuing difiiculty suflicient play can be given to the moving parts to allow for possible diiferences in expansion while keeping them free for their function; that no moving part is ever placed into communication with atomspheric pressureby leaks and that therefore such parts are never exposed to rapid temperature fluid from said pipe to either side of the piston and simultaneously to release fluid from the opposite side of the piston, a float rising and falling with changes in the water level of .the boiler, a conduit to carry said released fluid'to the boiler, and means extending through said conduit to actuate the pilot valve by the float; the arrangement being such that any leakage of feed water past the pilot valve is delivered to said conduit, wherebythe maximum pressure tending to cause leakage past the moving parts is the differential pressure between the pressure in the feed pipe and the pressure in the boiler.

AUGUSTE MAGIS.

Images