US2870775A - Regulating means for boiler feed pumps - Google Patents

Description

Jan. 27, 1959 G. wo o|:

REGULATING MEANS FOR BOILER FEED PUMPS Filed April 5, 1955 I REGULATING MEANS FOR BOILER FEED PUMPS George Wood, London, England, assignor to Vickers- Armstrongs Limited, London, England, a British com- Application April 5, 1955, Serial No. 499,468

Claims priority, application Great Britain May 24, 1954 3 Claims. (Cl. 13798) .for a boiler feed pump including a receiving chamber arranged for communication with a boiler steam take-off pipe through a valve device adapted to permit steam from said pipe to flow into the receiving chamber in quantities dependent upon the rate of steam flow in the pipe, a controlled outlet from said receiver and means for varying the pump output in response to steam pressure variations in said receiver.

In order that the invention may be clearly understood an embodiment thereof will now be described in detail with reference to the accompanying drawings in which:

Figure l is a part-sectional side elevation illustrating one form of regulating means in accordance with the inventon, and I Figure 2 is an end elevation showing a portion of the regulating means in partial section on the line II-II of Figure 1.

Referring now to the drawings, a flanged collar 1 is arranged for connection, with its axis substantially horizontal, in the steam take-elf pipe of a boiler, the interiorofthe collar providing a control chamber 1a in the aforesaid pipe. The collar 1 is provided with two diametrically opposed lateral external enlargements 2 each of which has an internal chamber 3 communicating with the control chamber 1a formed by the collar 1 through a short cylindrical passage 3a. A bar 4 is mounted diametrically across the control chamber In and has its opposite ends 4a extended axially through the respective cylindrical passages 3a into the lateral enlargement chambers 3, each bar end 4a being rotatably located by a roller bearing 5 provided in a recess 3b in the base of the associated chamber 3. Further bearings for the bar 4 are provided by two skirted pistons 6 which are arranged concentrically on the bar 4, one piston 6 being inset slightly from each bar end 4a. The pistons 6 are arranged to fit one in each cylindrical passage 3a extending between the enlargement chambers 3 and the control chamber 1a and are rotatable in these passages 3a. The piston skirts 6a are directed inwardly towards the control chamber 1a and around these skirts 6a are provided a number of radial apertures 7. The piston apertures 7 are arranged to register with corresponding radial apertures 8 which are formed through skirt portions 36 which project into the respective enlargement chambers 3 around the outer ends of the passages 3a. Thus by rotating the bar 4 and pistons 6, the apertures 7 and 8 formed respectively in the piston skirts and passage skirts can be brought more or less into register to provide variable ports connecting the control chamber 1a with the enlargement chambers 3.

Carried on the bar 4 so as to extend transversely across the control chamber 1a is a semi-circular vane or flap 9 the radius of which is only slightly smaller than the internal radius of the collar 1. The bar 4 will normally be rates tent mounted substantially horizontally and the vane 9 will thus have a bias of area and weight on one side of its fulcrum, provided by the axis of the bar 4, and will thus normally tend to hang down vertically within the control chamber 1a under gravity toprovide predetermined port openings. When steam is taken from the boiler and flows via the boiler steam take-01f pipe through the collar 1, the resistance to steam flow ofiered by the vane 9 will cause the latter to rotate or lift to a position in which the force exerted by the flow of steam balances the weight of the vane 9. Thus for varying rates of steam flow through the control chamber In the vane will assume certain corresponding angular positions and will correspondingly turn the bar 4 and the pistons 6 to provide pre-determined port openings.

Conduits 10, 10a communicate with the respective enlargement chambers 3, and extend from each such chamber to join a common conduit 11 through a conventional T-junction piece 12. The conduit 11 leads into the interior of a receiving chamber 13 which has two outlets 14 and 15 therefrom. The outlet 15 from the receiving chamber opens into a valve casing 16 through a variable restriction orifice 17, there being a branch outlet 18 from the casing 16 which may be connected with the feed pump exhaust or other convenient point in the steam system. To provide the variable restriction for the orifice 17, a seating 17a is arranged around the orifice for co-operation with a frusto-conical valve member 19 mounted on a screwed spindle 20, which can be screwed up and down with the aid of a hand-wheel 21 to raise or lower the valve 19 in relation to its seating 17a.

The second outlet 14 from the receiving chamber is connected,.through a conduit 22, with a cylinder 23 beneath a piston 24 working therein. This piston 24 is mounted concentrically on a valve stem 25 the lower end of which is provided with a valve member 26 which cooperates with a valve seating -27 to control a valve opening 28. This opening is situated between a passage 29, arranged for connection with a steam supply for a feed pump turbine, and a passage 30, arranged for connection with the feed pump turbine, so that the position of the valve member 26 determines the steam supply to the turbine and thus also the output of the pump. Above the piston 24, the valve stem 25 is associated with a coil spring 31 which tends to maintain the valve member 26 in thefully open position. Opening from the cylinder 23 above the piston 4 is a drain outlet 32.

The regulating means as described functions in the following manner.

For a given steam pressure in the boiler take-oft pipe and a given feed pump exhaust pressure or, in other words, for a given angular position of the vane 9 in the control chamber 1a and a pre-determined setting of the valve member 19 controlling the variable restriction orifice 17, a certain part of the steam will pass through the port openings 7, 8 into the conduits 10, 10a and 11 and thence into the receiving chamber 13. This steam, passing in turn through the variable restriction orifice 17, will automatically determine the pressure in the receiving chamber and so also the pressure acting on the valve stem piston 24. When this pressure acting on the piston 24 has built up sufiiciently to overcome the action of the spring 31, the valve will tend to close and thereby reduce or cutoff the supply of steam to the feed pump turbine to reduce the output of the feed pump. Thus, since the position of the vane in the control chamber 1a, which is connected in the boiler steam take-oil pipe, determines the position of the valve member 26 controlling the pump output, it follows that the rate of steam flow from the boiler will automatically control the rate of feed water supply to the boiler.

The operation of the vane 9 in the collar 1 is so atranged that the port openings decrease when the vane is lifted with increased steam flow, producing a corresponding reduction of pressure under the piston 24 which tends to permit the valve 26 to open under the action of the spring 31. When, however, steam vflow in the take-off pipe decreases sufi iciently to permit the flap 9 to fall into a vertical or near vertical position, the port openings 7 and 8 are then at a maximum and the pressure built up on the piston 24 tends to close the valve 26.

I claim:

1. A boiler feed Water regulator for a steam boiler having a steam take-ofi pipe including a coaxially mounted cylindrical collar, comprising a fluid-flow conduit for conducting pressure fluid to operate a means for supplying feed water to the steam boiler, a control valve in said fluid-flow conduit, a steam-receiving chamber, a steam conduit connected between the cylindrical collar of the steam take-ofl. pipe and the steam-receiving chamber for conducting steam from the pipe to the chamber, said collar including diametrically opposed laterally-extending skirted cylindrical passageways in its respective sides, a fulcrumed supporting member extending diametrically across said collar with its ends respectively extending into said passageways, a semi-circular vane carried by said fulcrumed member within said collar and tending to hang substantially vertically from the supporting member until angularly displaced by steam flow, said vane being adapted to take up angular positions dependent upon the force exerted thereon by the steam flow, said passageways being provided with radiallyextending apertures connected into the steam conduit, a control valve member carried on each end of said supporting member and located respectively in said skirted passageways, said valve members each comprising a skirted piston opening into said collar and provided with apertures registering with the apertures of the passageway in which it is mounted when the vane extends downwardly, the pistons being rotatable by the vane to progressively decrease the steam flow through the apertures to the steam conduit and chamber as the vane is fluid-flow conduit, said pressure responsive means being adapted to regulate said control valve in accordance with the changes in the steam pressure in the steam-receiving chamber resulting from variations in the rate of steam flow in the steam take off pipe. I

2. A regulator as claimed in claim 1, in which the steam-receiving chamber is provided with a steam exhaust outlet orifice, and valve means for controlling the orifice.

3. In a regulator for a steam boiler having a steam take-01f pipe, a steam conduit connected into the steam take-off pipe for conducting steam from the pipe, diametrically opposed laterally-extending cylindrical passageways in the respective sides of the steam take-01f pipe, a fulcrumed supporting member extending diametrically across said pipe with its ends respectively extending into said passageways, a semi-circular vane carried by said fulcrumed member within said pipe and tending to hang substantially vertically from the supporting member until angularly displaced by steam flow in the pipe, said vane being adapted to take up angular positions dependent upon the force exerted thereon by the steam flow, at least one of said cylindrical passageways being provided with radiallyextending apertures, means connecting said apertures into the steam conduit, a control valve member carried on the end of said supporting member located in said passageway provided with said apertures, said valve member comprising a skirted piston opening into said pipe the skirt of which is provided with apertures registering with the apertures in said passageway in which it is mounted when the vane extends downwardly, the piston being rotatable by the vane to progressively decrease the steam flow through the apertures to the steam conduit as the vane is lifted by increasing steam flow in the pipe.

References Cited in the file of this patent UNITED STATES PATENTS 311,145 Prunty Jan. 20, 1885 972,338 Collins Oct. 11, 1910 974,911 Parker Nov. 8, 1910 1,154,467 Wilkinson Sept. 21, 1915 1,154,591 Dodge Sept. 21, 1915 1,224,221 Schwanebeck May .1, 1917 1,280,477 Hopkins Oct. 1, 1918 2,414,629 Bloss Jan. 21, 1947 2,563,374 Rosenberger Aug. 7, 1951

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