US1947742A - Hydraulically-controlled valve - Google Patents

Description

Feb. 20, 1934. E L, SCHELLENS 1,947,742

HYDRAULICALLY CONTROLLED VALVE Filed OC-t. 19, 1931 Patented Feb. 20, 1934 nrDRAUucALLY-coNrRoLLED VALVE Eugene L. Schellens, Ridgewood, N. J., assignor to C-S Engineering Company, Englewood, N. J.. a corporation of Delaware Application October 19, 1931. Serial No. 569,653

13 Claims. (Cl. 137-139) This invention relates to hydraulically-controlled valves especially adapted although not necessarily restricted to control the supply of motive iluid to a turbine driven centrifugal pump i for the purpose of reducing the pressure of the motive duid, as steam, at the turbine in response to a failure of water pressure at the pump outlet for the purpose or" preventing the overspeeding or racing of the pump.

The invention is particularly useful in connection with a turbine driven centrifugal pump that supplies feed water to a locomotive boiler, where the supply of water to the pump can sometimes fail momentarily because of an air bubble in the suction line, or for some other reason. The valve with which this invention is particularly concerned includes a pressure balanced valve member having a small steam passage therethrough, the opening of which is controlled by a manually operated valve stem and which, when the valve member is in closed position, can pass an amount of steam into the turbine sulcient to maintain a small steam pressure therein for rotating the turbine and pump impeller at a reasonable speed when the pump is dry. The steam pressure, however, is not sufliciently high to cause the unit to race. The valve is provided with a piston one end of which is in communication with the pressure or outlet side of the pump. When the pump is supplied with water, the outlet pressure of the pump under the low steam pressure is suflciently great to move the piston to efect the opening of the valve member to admit full pressure steam to the turbine, which thus operates under normal speed to deliver water through the feed water heater into the boiler against the boiler pressure. When, however, the supply of water to the pump fails, the water pressure on the piston also fails and consequently the steam pressure closes the valve member immediately so that the pump and turbine can not race; and low pressure steam only is admitted to the turbine until water again flows into the pump. H

A feed Water supply system operating generally as above described is illustrated in the Schellens Patent No. 1,725,722, issued August 20, 1929.

In the valve disclosed in the aforesaid patent, the water actuated piston is connected with the movable valve member in such a way that there is the possibility that the feed Water, being at a. higher pressure than the steam pressure of the boiler, can leak by the piston into the steam passage of the valve and thereby be carried to the turbine and cause rapid wear of the turbine buckets. Hence, an object of the present invention is to isolate the water operated piston definitely from the movable valve member by providing the movable valve member with a separate pressure balancing piston; arranging an isolating partition wall between the adjacent ends of the valve and hydraulically-operated pistons; providing separate vents for the piston or leakage compartments on opposite sides of the partition Wall so that the water and steam conk densate can escape separately from the valve casing.

In some localities, the boiler feed Water contains scale-forming material which heretofore has interfered with the free movements of the water-actuated piston as scale is deposited between the piston and the side Wall of the cylinder in which it operates due to the fact that the piston and the side Wall become highly heated by reason of the conduction of heat through the metal wall I5 of the valve from the steam end thereof.'

It is a further object of this invention to insulate the water-actuated piston and its supporting parts against the heat of the steam end of the valve casing, thereby tokeep the piston 8l)` and its associated parts su'iciently Acool to prevent deposition of scale forming material.

A further object of the invention is generally to improve the construction and operation of hydraulically-controlled valves.

The figure is a section of a valve embodying the present invention, the section being taken through the longitudinal axis of the valve.'

As here shown, the valve comprises the valve casing 10 having a steam entrance passage 12, a steam outlet passage 14 and a partition wall 16 separating the passages and having a ported valve seat 18 therein. A movable valve member 20 is located in said passage and is guided for axial movement therein by ribs 22. The hub 24 of the valve member has a passage 26 therein of small cross-sectional area which permits small amounts of steam to pass through the valve when the valve member is in closed position on the seat 18. The'outlet of said steam passage 26 is controlled by a manually operated valve stem 28 which has a screw threaded connection with the removable valve cap 30 and a conical seat 32 which can seat in the end of the passage 26to close said passage and also to hold the valve member 20 on its seat 18.

The valve casing 10 is provided with a cylinder extension 34 having a cylinder sleeve 36 therein in which a piston 38 is located. Said piston has a stem 40 which is received in a tongued slot in 110 leaks past the piston can escape.

said pressure serves to hold the valve member 20 Y positively against its seat when the turbine driven pump is dry. As has been stated heretofore, the amount of steam that can be passed through the small passage 26 is sunicient to cause the turbine to operate the dry pump at a reasonable rate of speed but is not sufcent to cause the pump to overspeed or race.

The outer end of said piston 38 is located in an exhaust or leakage chamber 42 which is vented freely to the atmosphere through a vent passage 44 at the bottom of the chamber. Thus steam that passes by the piston, and any condensate that is formed, escapes from the valve through the passage 44. A cylinder casing 46 for a wateroperated piston is disposed in confronting and `aligned relation with the cylinder extension 84 and is secured in such relation by a pair of diametrically opposed stud bolts 48, one of which is illustrated in the iigure, which stud bolts are screw-threaded into outstanding lugs 50 of the cylinder extension 34 and pass through lugs 52 of the cylinder casing and have nuts 54 removably screw-threaded on the free ends thereof.

The cylinder casing 46 is provided with a cylinder sleeve 56 therein which is axially aligned with the cylinder sleeve 36 of the movable valve member. A piston 58 is located in said cylinder and has one end located in an exhaust or leakage compartment 60 which confronts the exhaust or leakage compartment 42 and its other end located in a pressure chamber 62. Water from the outlet of the turbine driven pump is supplied to said chamber through an inlet passage 64. The leakage chamber V60 is vented at its lowermost part either to the atmosphere or to the inlet of the pump as may be desired through an outlet passage 66 through which boiler feed water that The leakage compartments 42 and 60 are isolated from each other by a partition member 68 which as an outstanding ilange 70 that is located between the confronting ends of the cylinder extension and cylinder casing and is seated against both and has circular flanges '72 which t in the confronting open ends of the leakage compartments to hold the parts in axial alignment. The partition member is clamped between said cylinder extension and the cylinder casing by the aforesaid bolts 48 and nuts 54. Thus the two leakage compartments are isolated-from each other so that water and steam, or steam condensate, that leak past their respective pistons are caused to be discharged separately from the Valve without commingling within the casings. Said partition member 68 is constructed of heat insulating material, as a molded composition of asbestos and rubber, or the like, and thus serves to insulate -l the cylinder casing 46 from the heated valve casing. Hence the cylinder casing and the water that leaks past the piston 58 remains cool and consequently deposition of the scale forming material around the piston is practically eliminated.

' f While some heat can be transmitted to the cylinder casing through the bolts 48, the cross-sectional area of the bolts is so small that the amount of heat transmitted is negligible and less than can be readily dissipated by radiation by the cylinder casing.

Motion is transmitted from the Water-actuated piston 58 to the piston 38 of the valve member by means of a rod 74 which has a small diameter as compared with the diameter of the aforesaid pistons and closely i'lts within and is slidable axially of the pistons in a bearing tube 76 that is carried by and is molded in the partition member 68. Said rod has its opposite ends terminated in confronting relation with and adapted to be abutted against by the adjacent ends of the pistons. Movement of the piston 58 toward the right under inuence of a normal feed water pressure is transmitted through the rod 74 and the piston 38 and thence to the valve member 20 whereby to move the valve member into open position and admit full pressure steam to the pump turbine. When the pump pressure fails for any reason so that the load on the pump turbine is reduced and pressure on the piston 38 is reduced or disappears, the steam pressure in the outlet passage 14 acts on the valve to move it into closed position, whence it will again be moved into open position when the water pressure is restored.

The valve as above described is practically entirely free from scale formation. The wateractuated piston 58 is maintained at a low temperature, by being isolated from the heat of the steam space of the valve, so that the water that leaks past the piston has no tendency to deposit 11D scale. The leakage feed water can not come in contact with the piston 38 so that no scale can be deposited thereon or on its cylinder walls. The rod 74 is free from leakage feed water since it is above the outlet 65 and is also at a low 115 temperature. Thus the valve can function with reliability regardless of the presence of scale forming materials in the feed water.

I claim:

l. A hydraulically-operated valve comprising 120 a valve casing, a valve member therein, means including a balancing piston connected with said Valve member for holding said valve member closed by the pressure in said casing, a hydraulically-operated piston opposed to said balancing 125 piston and acted on by pressure fluid at one end for moving said Valve member to open positon, casing means providing separately-vented leakage chambers open to the confronting ends of said pistons, means including a partition wall 134 common to both chambers for isolating them from each other, and means for transmitting motion between the pistons.

2. A hydraulically-operated valve comprising a valve casing, a valve member therein, means 135 including a balancing piston connected with said valve member for holding said valve member closed by the pressure in said casing, a hydraulically operated piston opposed to said balancing piston and acted on by pressure fluid at one end 146 for moving said valve member to open position, casing means providing separately-vented leakage chambers open to the confronting ends of said pistons, means including a partition wall common to both chambers for isolating them 145 from each other, and means free from positive connection with said pistons for transmitting motion between the pistons through said common partition wall.

3. A valve as defined in claim 1 wherein said l5@ partition wall is composed of heat-insulating material.

4. A hydraulically-operated valve comprising a valve casing, a valve member therein, means including a balancing piston connected with said valve member for holding said valve member closed by the pressure in said casing, a hydraulically-operated piston opposed to said balancing piston and acted on by pressure fluid at one end for moving said valve member to open position, casing means providing separately-vented leakage chambers open to the confronting ends of said pistons and having confronting open ends, a partition wall common to both chambers for closing said open ends and for isolating said chambers from each other, and means for transmitting motion between the pistons.

5. A hydraulically-operated valve comprising opposed hydraulically-operated and valve-controlling pistons, casing means providing separately-vented chambers open to the confronting ends of said pistons, a partition Wall common to both chambers for isolating them from each other, and means for transmitting motion between the pistons comprising a rod separate from both of said pistons extended through and slidable in said partition wall and arranged to abut against the confronting ends of the pistons.

6. A hydraulically-operated valve comprising opposed hydraulically-operated and valve-controlling pistons, casing means providing separately-vented chambers open to the confronting ends of said pistons, and having confronting open ends, a partition wall common to both chambers for closing said open ends and for isolating said chambers from each other, and means for transmitting motion between said pistons including a rod which is separate from both or" said pistons and is extended through and is slidable in said partition wall and is arranged to abut against the confronting ends of said pistons.

7.1A valve as defined in claim 6 wherein said partition wall is heat-insulating.

8. A hydraulically-operated valve comprising a valve casing having steam inlet and outlet passages, a leakage compartment, and a cylinder open to said steam inlet passage and said leakage compartment, a piston in said cylinder, a movable valve member connected with said piston for controlling communication between said steam passages, means including said piston and valve member for holding said valve member closed by the pressure in said casing, a cylinder casing having a pressure chamber, a leakage compartment and a cylinder open to both, a piston in said cylinder means for subjecting said piston to pressure fluid in a direction to effect the opening of said Valve member, a partition wall conimon to both leakage compartments for isolating them from each other, a separate vent passage for each compartment, and means for transmitting motion between said pistons.

9. A hydraulically-operated valve comprising a valve casing having steam inlet and outlet passages, a leakage compartment, a cylinder open to said steam inlet passage and said leakage compartment, a piston in said cylinder, a movable valve connected with said piston for controlling communication between said steam passages, a cylinder casing having a pressure chamber, a leakage compartment and a cylinder open to both, a piston in said cylinder, a heat-insulating partition wall common to both compartments for isolating them from each other and for insulating said cylinder casing from the heat of said valve casing, a separate vent passage for each compartment, and means for transmitting motion between said pistons.

10. A hydraulically-operated valve comprising a valve casing having steam inlet and outlet passages, a leakage compartment, a cylinder open to said steam inlet passage and said leakage compartment, a piston in said cylinder, a movable valve connected with said piston for controlling communication between said steam passages, a cylinder casing having a pressure chamber, a leakage compartment and a cylinder open to both a piston in said cylinder, a heat-insulating partition wall common to both compartments for isolating them from each other and for insulating said cylinder casing from the heat of said valve casing, a separate vent passage for each compartment, and means for transmitting motion between said pistons comprising a rod carried by and slidable in said insulating wall and adapted to engage both pistons.

11. A valve as defined in claim 10 wherein said rod abuts against the ends of and is free from positive connection with said pistons.

12. A hydraulically-controlled valve comprising a valve casing having a steam passage therein, a movable Valve member controlling the ow of steam in said passage, a hydraulically-operated piston for controlling said valve member, a cylinder casing containing said piston, and a heat insulating plate interposed between and upon which both casings are seated and which insulates said cylinder casing against the heat of said valve casing.

13. A hydraulically-controlled valve comprising a valve casing having a steam passage therein, and an open ended cylinder extension, a piston in said extension, a movable valve member connected with said piston and controlling the ow of steam in said passage, a cylinder casing having an open end confronting the open end of said cylinder extension, an insulating plate located between and separating both casings, a hydraulically-operated piston in said cylinder casing, and a rod slidable in said plate for transferring motion between said pistons.

EUGENE L. SCHELLENS.

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