US2159345A - Boiler feed apparatus - Google Patents

Description

May 23, 1939. R STROBEL 2,159,345

BOILER FEED APPARATUS Filed Dec. 20, 1957 2 Sheets-Sheet l 52 51 7;? 7'0 2 6' 50 71 1072 HHI j;g 35.9 35 5 34 gwucwfor, 36 01 6. AW

52 47 40 (ya/f5 x fllto muw Patented May 23, 1939 UNITED STATES PATENT OFFICE BOILER, FEED APPARATUS Application December 20, 1937, Serial No. 180,839

11 Claims.

This invention relates to feed-water apparatus for boilers, and the general object of the invention is to provide a simple apparatus for this purpose, which will operate automatically to admit feed-water to the boiler whenthe boiler level falls to a predetermined point. In its preferred embodiment, the invention employs a feed-water holder located at a higher level than the boiler, so that the feed-water can flow by gravity from the same into the boiler; and one of the objects of the invention is to provide improved means for normally maintaining the boiler steam pressure on the surface of the feed-water in the feedwater holder, and for automatically cutting off the supply or" live steam to thefee'd-water holder and simultaneously exhausting the holder after the feed-water has substantially drained from the holder into the boiler.

A further object of the invention is to provide a system of boiler feed apparatus, which can operate without including in it, stuffing boxes or other parts requiring attention.

A further object of the invention is to provide the system with means for automatically effecting a refilling of 'the'feed water holder whenever the samehas been discharged into the boiler. w

Further objects of the invention will appear hereinafter.

The invention consists in the novel parts and combination of parts to be described hereinafter, all of which contribute to produce an efficient boiler feed apparatus.

A preferred embodiment of the invention is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawings:

Fig. l is a diagrammatic general arrangement of the apparatus, certain partsb'eing broken away or shown in section, and showing the apparatus with the parts in the relation which they have under normal conditions, and ready to feed water into the boiler as soon as the water level drops to the lower limit.

Fig. 2'is' a vertical section taken through a conrol device activated by the emptying of the feedwater holder, and showing details of the same and contiguous parts.

Fig. 3 is a vertical section upon an enlarged scale in detail, illustrating the steam valve and contiguous parts broken away.

Fig. 4 is a diagrammatic View, certain parts being broken away or shown in section, and lustrating the apparatus with the parts in the relation they have when the feed water is flowing through into the boiler.

In the drawings, l indicates a boiler of any common type having a steam dome 2 from which the steam pipe line 3 leads. 'In practicing the invention, I provide a control device 4, which is activated by the agency of the water level of the boiler indicated by the dotted line la. This control device 4 in Fig. 4, is illustrated as including an outer casing 5 and a float S.' This float controls a release valve 1' similar to the release valve 8'illustrated in detail in Fig. 2, and which is associated with the feed-water holder as will be described hereinafter. The float E is supported on an arm 9 pivoted at IB, and the float members include'a relatively light float body ll of aluminum or similar material, and a body [2 of lead or similar material located beyond the pivot point H] with respect tothe body II. I prefer to construot the body II of solid aluminum because this is superior to the use of a sealed hollow body which may commence to leak after long use, and render the apparatus unreliable.

The casing or float chamber 5 is connected by a pipe I3 with the interior of the boiler below the water level, and by another pipe M with the interior of the boiler above the water level. This maintains a balance of pressures in the control device}, and enables the water level within it to rise and fall with the water level of the boiler, which is usually provided with a sight gauge l5 f orindicating the position of the water level.

Preferablyabove the level of the boiler I provide a feed- -water holder l6, which is connected by a feed-water pipe ll, to the boiler below the water line of the same, and this feed-water line has a pressure-controlled valve device It in it, the closure 19 of which is normally held down on its seat by a weight 20 in the cylindrical casing 2i forming a bonnet on the valve casing. This weightrests on the upper end of a bellows 22 within the bonnet 2|. The head of the bellows carries an operating stem 22a attached to valve l9. Between the valve device l8 and the boiler the feed-water line ll carries a check valve 23 that opens toward the boiler and checks back pressure from the boiler against reaching the valve device 18. The steam line 3 from the boiler has an extension 24 that is connected'with the upper end of the tubular casing 2| and maintains boiler steam pressure on the top of the bellows 22, thereby normally holding the valve closure I9 down and on its seat against the hydrostatic head, and so as to normally prevent flow of feed-water to the boiler. 'When the release valve 7 is in its closed position, the boiler pressure existing in chamber is balanced by the equal pressure existing in pipe l7. When the water level Ia of the boiler drops sufficiently, the float 6 will move into a position such as that indicated in Fig. 4, thereby releasing the pressure from the chamber 25 above the Weight 25. This release of pressure from the chamber 25 is effected by the release valve 1, which has a construction similar to that illustrated in Fig. 2. The inlet side of this valve 1 is connected by a short pipe 25 with the pipe 24, and the outlet of the valve is connected by a vent pipe 2? to a feed-water heater tank 28. In the pipe line 24 just forward of the branch line 26 to this valve,

with respect to the direction of flow of the steam, I provide a bleeder valve 29. This bleeder valve permits some water to pass, but not sufiicient water to prevent the exhaust of pressure from the chamber 25 when the release valve opens. The construction of this release valve as indicated above, is substantially the same as that of the release valve 8, which is illustrated in detail in Fig. 2, and which will be presently described.

The release valve 8 is preferably carried in a float chamber 30 mounted in the interior of the feed-water holder [6 and provided with a float 31 for controlling the release valve, which float is activated to open the release valve 8 when the Water level in the feed-water holder falls sufficiently; in other words, when the feed-water holder is substantially empty by draining itself into the boiler. The release valve 8, when actuated by the falling of the float 3|, operates a steam valve 32, which valve normally maintains steam pressure on the surface of the feed-water in the holder It. This valve 32, when activated by the opening of the release valve 8, operates to shut off the supply of live steam to the steam space 33 above the feed-water, and opens this space to exhaust. For this purpose I prefer to construct the valve 32 as a combined inlet and exhaust valve, both closures of which are actuated simultaneously so that when the inlet is open the outlet is closed, or vice versa. For this purpose this valve has a live steam valve chest 34 and an exhaust chamber or outlet chamber 35. In the former a ball valve 36 moves downwardly upon its seat 31, while in the exhaust chamber or outlet chamber a ball valve 38 comes upon its seat 39 by an upward movement. These two ball valves are carried on short stems attached to a cross-head 4|] (see Fig. 3) and this cross-head is actuated by a pressure-controlled device 4|, which is supplied with condensed steam through a branch pipe 42 with a lateral connection 43, which normally maintains live steam pressure in the pressure chamber 44 within the casing of this device, so that the steam pressure exerts itself upon the lower end of a bellows 45. This bellows is connected with a long stem 46 of reduced diameter with a guide bar 41 of relatively larger diameter, which guide bar 41 carries a cross-head 40. The chamber within the bellows is full of water, and this makes it necessary to provide a relatively long tubular guide 48 between the steam valve and the bellows, to insure that the.

Water within the bellows will not rise to the boiling point. If this occurred, it would interfere with the reliable operation of this device by boiling the water or condensed steam that fills the pressure chamber 44. It is desirable to maintain water only in this chamber in order to have a positive and rapid movement of valves 36 and 38 in response to operation of relief valve 8, and

also to prevent bouncing or pounding of main steam inlet valve 36 which would have a destructive effect on bellows 45.

The pipe 3 should function as a steam condenser. This insures the presence of water in the control circuit instead of steam. For this purpose, this connection should include a con denser, or should be provided with a plurality of radiator fins 3a of sufficient total area to insure that water (condensed steam) stands in the pipe connection of the control circuit leading to valves 1 and 8.

In the branch pipe 42 I provide a bleeder valve 49, which will supply sufficient condensed steam to maintain the live steam pressure on the water in the chamber 44, but which will not interfere with the release of this pressure when the release valve 8 is operated.

The outlet side of the release valve 3 is connected to a vent pipe 50, which may extend down and connect to the aforesaid vent pipe 2?.

The interior of the steam valve 32 is supplied with live steam through a branch pipe 5! from the live steam pipe 3, and the outlet chamber or exhaust chamber 35 is connected to an exhaust pipe 52 that carries away the exhaust steam that can flow through the valve 32 and through the outlet pipe 52a from the steam chamber 33 of the feed water holder i6. I prefer to employ the,

exhaust steam to heat the feed water in the feed Water heater 28, for which purpose the pipe 52 connects at its end to a submerged coil 53 in the feed water heater. Of course, the feed water becomes heated in the holder, but this tank or feed water heater 28 may be considered a preheater for the feed water.

Between the interior of the float chamber 33 and the interior of the feed water holder iii, a check valve outlet is provided, permitting water to flow out of the float chamber 30 when the feed water holder [6 has substantially drained. If desired, this connection may include a pipe 55 connected at one end to the float chamber 33, and at the other end to the interior of the feed water holder, and this pipe carries a check valve 55 that opens toward the interior of the feed water holder. This insures that the float chamber 30 can only be supplied with water from an elevated pipe connection 56 that only supplies water to the float chamber 30 when the feed water holder is completely full. It will be noted that the steam valve is not actuated until the feed water holder l6 has substantially drained itself into the boiler. When this occurs, the release valve 8 releases the pressure from the pressure chamber 44' of the pressure control device 4|, and this permits the ball valve 36 to move down onto its seat 31; at the same time, through the action of the cross-head 40, the exhaust valve 38 will be opened and this will exhaust the steam from the steam chamber 33. These operations occur preparatory to refilling the feed water holder Hi. This may be accomplished by the gravity flow of water from an elevated feed water pre-heater, but in the present instance, as the feed water pre-heater 28 is below the level of the feed water holder, I may employ means for creating a partial vacuum in the chamber 33 so as to suck Water up from the pre-heater 28. For this purpose I may provide a spray nozzle 57 supplied with water through a branch pipe 58 a connected to a cold water supply 59. This cold water supply pipe 59 may have a valve 63 normally left open, and the branch pipe 58 is provided with a check valve (it that permits this water to flow through when the pressure is reduced in the chamber 33, but this valve iii, of course, checks back pressure in the pipe 58 from the chamber 33.

The spray through the spray nozzle delivered into the empty feed water holder, which has just drained, will condense the exhaust steam still remaining in this chamber, and create a partial vacuum which causes suction through a suction pipe 62 that leads up to a lower level in the preheater 28, and connects at its upper end to the pipe I already referred to. At the lower end of this suction pipe 62 a check valve 63 is provided, which permits upward flow of water, but checks back pressure from the feed water holder.

In the exhaust line 52 it is also necessary to provide a check valve 64, which permits out flow of exhaust steam from the steam valve, but which checks back pressure from the coil 53. This is necessary to prevent the partial vacuum being broken when it is being formed by condensing steam in the chamber 33.

A float control valve 65 may be provided at the lower end of the supply branch pipe 66, that connects with the water supply pipe 59. This valve 55 is controlled by a float 66a, and automatically maintains the proper water level in the preheat-er 28.

The live steam line 3, of course, should be provided with a valve 61 for controlling delivery of steam through it. It will be noted that none of the moving parts of the valves or other mechanisms involve the use of stufling boxes. The use of stufling boxes is also avoided in the construction of the release valves 1 and 8. The release valve 8 and the parts for controlling the same, are fully illustrated in Fig. 2. This valve has an inlet passage 42a supplied with steam through the pipe 42 and delivers live steam into the valve chamber 68. This chamber is normally closed by the conical tip of the needle E59, and when this needle 69 is off its seat, the chamber 58 communicates with the outlet passage 50a that communicates with the pipe 59. In order to avoid the use of stuffing boxes for this needle 63, and at the same time, to balance the pressure on the needle, the needle at about the middle point of its length, carries a guide head 10 capable of moving laterally in the bore of a cylindrical guide H. This guide head H! has a socket 12 on its upper side, that receives the end of an arm 13 that projects down from the outer end of the arm 9, which is mounted on the pivot lil. The forward side of the head ill is provided with a bellows 'M, the interior of which is exposed to the steam pressure from the passage 68 when the valve is open. In order to balance this pressure, Iprovide a balancing bellows 15 on the opposite side of the head l0, and the interiors of these two bellows are connected by a drilled passage 16. The end of the needle 69 near its conical tip is guided in a guide opening 1'! in a casing at this point, and the back end of the needle 68 is guided in a cap 18 at the rear of the casing.

The ball closures 3'! and 38 for the steam valve 32, are preferably made of stainless steel.

The advantages of this system of apparatus, are that it is capable of operating with water of any temperature, and from any source. In the apparatus, no packed stems, trunnions, or joints are employed, which would leak, become worn or become stuck and fail to operate. The non-thermostatic method of control of the steam valve actuator is positive, simple, and will operate satisfactorily over a wide range of steam and water temperatures and pressures without necessitating adjustments. There is no waste of steam or hot water, and all condensed water is collected in the pre-heater 28 and returned to the boiler.

There are no parts such as piston rods, piston rings, cylinders, or pump valves, which are subject to wear, and must be replaced. The check valves used in the steam and water lines are all outside valves, and therefore easy to inspect or replace.

The feed line and boiler pressure differential is very low and is only that due to the actual head of the feed water level in the feed water holder. The system, being devoid of fast moving parts such as motors, pumps, etc., operates Without noise, and with low upkeep cost.

The mode of operation of the entire system will now be briefly restated:

In the normal condition, that is to say, when the boiler level id is above the minimum low point, the steam valve 32 is open, that is to say, the ball valve 36 is 01f its seat and live steam from the steam line 3 is maintained in the steam chamber 33 of the feed water heater. When the level la drops below the minimum level, the float 6 will swing down toward its left end, thereby opening the release valve l. This permits exhaust of water from the chamber 25 of the pressure control valve Hi, the water from chamber 25 finding an outlet through the release valve 1 and through the outlet pipe 2'! to the pre-heater 23. The release of the pressure in the chamber 2 permits the valve closure [9 to rise off its seat due to the resiliency of the bellows 22 and the water pressure under the valve closure IS, which water pressure is, of course, increased by the steam pressure in the feed Water holder l5. As soon as the valve closure l9 rises off its seat, the feed water in the holder l5 flows through this feed valve and past the check valve 23 into the boiler. This continues until the feed. water holder IE is substantially drained. When this occurs, the water in the float chamber 30 will have completely drained through the connection 54 and check valve 55, whereupon the float 3| will swing down toward its left end and open the release valve 3. The opening of this release valve 8 releases the water pressure from the chamber M surrounding the bellows 45, and this will cause the guide bar A? and cross head 4-0 to descend, thereby closing the steam valve 36 and opening the exhaust valve 38, thus permitting the live steam in the chamber 33 to pass out through the coil 53 in which this steam will be condensed. As soon as the steam pressure in the chamber 33 becomes sufficiently reduced, the water pressure in the water and supply line 59 will open the check valve 6i and permit water to pass into the spray nozzle 51. This will spray the interior of the chamber 33 and cause a condensation of any steam remaining in it. This will produce a partial vacuum and develop a suction eflect in the suction pipe 2, which will suck up water from the pre-heater 22 and deliver it into the interior of the feed water holder. When the feed water holder is completely full, water will flow down the connection 55 into the float chamber 5%), which will cause the float 31 to go back to its closed position. It will then supply condensed steam or water under full. steam pressure from condenser vertical pipe 3 to the chamber M, and this will move the cross-head 4 carrying the ball valves 35 and 38, moving the same up so as to open the ball valve 36 and close the valve 38.

It is understood that the embodiment of the invention described herein is only one of the many embodiments this invention may take, and I do not wish to be limited in the practice of the invention, nor in the claims, to the particular embodiment set forth.

What I claim is:

1. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-Water holder above the water level therein, pressure-controlled means associated with the said valve for opening the same, means for controlling the last-named means through the agency of the water level in the boiler to eifect the opening of the valve when the water level reaches the lower limit, to drain the feed-water holder into the boiler, and means associated with the feed-water holder and activated by the substantial draining of the feed-water holder, for shutting off the admission of steam from the boiler to the feed-water holder, and for permitting the escape of the steam within the feed-water holder.

2. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, pressure-controlled means associated with the said valve for opening the same, means for controlling the last-named means through the agency of the water level in the boiler to effect the opening of the valve when the water level reaches the lower limit, to drain the feedwater holder into the boiler, means associated with the feed-water holder and activated by the substantial draining of the feed-water holder, for shutting off the admission of steam from the boiler to the feed-water holder, and for permittingthe escape of the steam within the feed-water holder, and means for effecting the refilling of the feedwater holder and for reclosing the said feed valve.

3. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, pressure-controlled means associated with the said valve for opening the same, means for controlling the last-named means through the agency of the water level in the boiler to efiect the opening of the valve when the water level reaches the lower limit, to drain the feed-water holder into the boiler, means asso-' ciated with the feed-water holder and activated by the substantial draining of the feed-water holder, for shutting off the admission of steam from the boiler to the feed-water holder, and for permitting the escape of the steam within the feed-water holder, means'for condensing the exhaust steam in said feed-water holder thereafter to develop a partial'vacuum therein, and a suction feed pipe connected to the feed-water holder for raising water from a lower level to the feed water holder.

4. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, pressure-controlled means associated with the said valve for opening the same, means for controlling the last-named means through the agency of the water level in the boiler to effect the opening of the valve when the water level reaches the lower limit, to drain the feedwater holder into the boiler, a steam valve in the steam line for controlling admission to, and release of, steam from the feed-water holder, and pressure-controlled means activated by the substantial draining of the feed-water holder for actuating the steam valve to shut off the flow of steam from the boiler and release the steam pres-,- sure from the feed-water holder preparatory to refilling the same.

5. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to-the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, a pressure-controlled means associated with the said valve for opening the same, means for controlling the last-named means through the agency of the water level in the boiler to eifect the opening of the valve when the water level reaches the lower limit, to drain the feed-water holder into the boiler, a steam valve in the steam line, said steam valve having an inlet for live steam and an exhaust outlet communicating with the interior of the valve, with a connection from the interior of the valve to the interior of the feedwater holder, a closure corresponding to the steam inlet, and a closure corresponding to the exhaust outlet, a member connected with both of said closures for operating the same in unison, and pressure-actuated means for actuating said member with means for activating the same through the agency of the substantial draining of the feed-water holder, said parts cooperating so that when the live steam inlet is open the exhaust outlet is closed, and so that when the steam inlet is closed the exhaust outlet is open.

6. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to'the upper portion of the interior of thelfeed-water holder above the water level therein, a pressure-controlled means associated with the said valve for opening the same, means for controlling the last-named means through the agency of the water level in the boiler to effect the opening of the valve when the water level reaches the lower limit,'to drain the feed-water holder into the boiler, a steam valve in the steam line, said steam valve having an inlet for live steam and an exhaust outlet communicating with the interior of the valve and connected to the feedwater holder above the water line therein and operating normally to maintain the live steam pressure of the boiler on the upper surface of the feed-water in the feed-water holder, and

pressure-operated means, with means for actiboiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, a pressure-controlled means associated with the said valve for opening the same, means for controlling the last-named means through the agency of the water level in the boiler to effect the opening of the valve when the water level reaches the lower limit, to drain the feed-water holder into the boiler, a steam valve in the steam line, said steam valve having an inlet for live steam and an exhaust outlet communicating with the interior of the valve and connected to the feedwater holder above the water line therein, and operating normally to maintain the live steam pressure of the boiler on the upper surface of the feed-water in the feed-water holder, pressure-operated means, with means for activating the same by the agency of the substantial draining of the feed-water holder, for closing the live steam inlet and opening the exhaust outlet, and means for effecting the refilling of the feedwater holder after the same has drained into the boiler.

8. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, a pressure-controlled means associated with the said valve for opening the same, means for controlling the last-named means through the agency of the Water level in the boiler to effect the openingv of the valve when the water level reaches the lower limit, to drain the feed-water holder into the boiler, a steam valve in the steam line having means for controlling admission of live steam to the feed water holder and exhaust of steam from the feed water holder, said valve having an operating stem extending therefrom, an elongated guide for said stem, a pressure-controlled bellows connected with the end of said stem, a casing enclosing said bellows and having a pressure chamber therein surrounding the bellows, and means for controlling the pressure in said pressure chamber, activated by the substantial draining of the feed water from the feed water holder for controlling said valve stem to close the steam inlet and open the exhaust outlet.

9. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, a pressure-controlled means associated with the said valve for opening the same, means for controlling the lastnamed means through the agency of the water level in the boiler to effect the opening of the valve when the water level reaches the lower limit, to drain the feed-water holder into the boiler, a steam valve in the steam line having means for controlling admission of live steam to the feed-water holder and exhaust of steam from the feed-water holder, said valve having an operating stem extending therefrom, an elongated guide for said stem, a pressure-controlled bellows connected with the end of said stem, a casing enclosing said bellows and having a pressure chamber therein surrounding the bellows, means for normally maintaining pressure at the bellows to hold the steam valve in a position to admit live steam to the feed-water holder, and a release valve With means for automatically actuating the same through the agency of the substantial draining of the feed-Water holder to open the release valve and release the pressure from the said bellows, said bellows actuating the steam valve thereafter to shut oil the admission of steam to the feed-water holder and open the interior of the feed water holder to exhaust.

10. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, a pressure-controlled means associated with the said valve for opening the same, means for controlling the lastnamed means through the agency of the water level in the boiler to effect the opening of the valve when the water level reaches the lower limit, to drain the feed-Water holder into the boiler, means associated with the feed-water holder and activated by the substantial draining of the feed-water holder, for shutting off the admission of steam from the boiler to the feed- Water holder, and for permitting the escape of the steam within the feed-water holder, said feed valve having a valve seat and a closure mounted so as to move away from its seat in the direction of flow of the feed-water toward the boiler, and a check valve in the feed line between the feed valve and the boiler permitting flow from the feed valve to the boiler but preventing communication of the boiler pressure from the boiler to the said closure.

11. In a boiler feed apparatus, the combination of a feed-water holder at an elevation above the boiler level, a feeder pipe for delivering water from the feed-water holder to the boiler, a normally closed feed valve in said pipe, a steam line for admitting steam from the boiler to the upper portion of the interior of the feed-water holder above the water level therein, a pressure-controlled means associated with the said valve for opening the same, means for controlling the lastnamed means through the agency of the water level in the boiler to effect the opening of the valve when the Water level reaches the lower limit, to drain the feed-Water holder into the boiler, a steam Valve in the steam line for controlling admission to, and release of, steam from the feed-water holder, a float-controlled means including a float activated by a fall in the level of the water in the feed-water holder, and pressure-controlled means activated by said float and connected with the steam valve to operate the same to shut ofi admission of the live steam to the feed-Water holder, and to release the steam pressure from the feed-water holder preparatory to refilling the same.

ROY E. STROBEL.

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