US1198635A - Heat-balancing valve. - Google Patents

Description

UNITED STATES PATENT OFFICE.

FRANCIS HODGKINSON, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE WEST- INGHOUSE MACHINE COMPANY, A CORPORATION OF PENNSYLVANIA.

HEAT-BALANCING VALVE.

Specification of Letters Patent.

Patented Sept. 19, 1916.

To all whom it may concern Be 1t known that I, FRANCIS HoDoKrNsoN,

I a subject of the King of Great Britain and Ireland, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Heat-Balancing Valves, of which the following is a specification.

This invention broadly relates to the conservation of motive fluid in connection with installations including an engine or fluid actuated motor, to which high pressure motive fluid is delivered, and a heating system to which low pressure fluid is delivered and in which it is necessary or desirable to maintain a substantially constant pressure.

As an example of an installation or organized apparatus with which apparatusembodying my invention may be employed, reference may be made to the modern power plant, in which the main power units receive high pressuremotive fluid, (hereinafter called steam or live steam) and the low pressure fluid, (hereinafter called steam or exhaust steam) exhausted from auxiliary units, such as engines for driving pumps, etc., is employed in heating the feed water delivered to the steam generators supplying live steam to the main power units and to the auxiliary units.

The amount of steam exhausted from the auxiliaries is substantially constant, regardless of variations in load on the main power units, whereas variations in load on the main power units necessitate variations in the amount of steam generated and consequently in the amount of feed water supplied to the generators. For this reason, it is difllcult to so proportion the power or the number of auxiliary units, delivering exhaust steam to the feed water heater, that the amount of steam delivered to the heater will always correspond to the heaters requirements. There is generally an excess of steam available for feed water heating during periods of light load on the main power units and consequently the surplus exhaust steam is wasted unless some means is employed for utilizing it. On the other hand, there is usually an insufficient amount of ex haust steam, available from the auxiliaries,

during periods of heavy loads on the main power units and, as a result, the feed water is not heated to the desired temperature.

Automatic means have been employed for augmenting the exhaust steam delivered to the feed water heaters during periods of heavy loads on the power units by bleeding steam from a working passage of a power unit and delivering it to the heater. Automatic means have also been employed for conserving the excess exhaust steam delivered to the heater during periods of light load on the main units by delivering it to a working passage of a power unit. This is usually accomplished by providing a bleeder port at such a point in the working passage of a main power unit that the pressure at the port approximates as nearly as possible the pressure it is desired to maintain within the heater. The excess steam from the heater is fed into the power unit through this bleeder port, during periods of light load on the power unit, and an augmenting supply of steam is delivered from the working passage of the power unit through the bleeder port to the heater when the exhaust steam delivered to the heater from the auxiliaries is insufficient to maintain the feed water at the desired temperature. The objection to such an arrangement of apparatus is that the auxiliaries must exhaust against the pressure obtaining at the bleeder port which, under certain load conditions of the main power unit, may be many pounds above atmosphere or the pressure which it is desired to maintain in the heater. If this difliculty is avoided by so locating the bleeder port with relation to the working passage of the power unit that the pressure at the port will never exceed a desired exhaust pressure for the auxiliaries, the ratio of expansion of the steam exhausted from the auxil iaries would be lower than desirable andobjectionable, in that it could not be economically employed in the main power unit during periods of normal and light loads.

Apparatus has also been employed for automaticallyclosing communication between the exhaust of the auxiliary units and the power unit when the pressure at the bleeder port of the power unit exceeds a desired or determined pressure, or a pressure above which it is undesirable to exhaust the auxiliary units. Such apparatus does not fulfil requirements, since at periods, during which the pressure at the bleeder port of the power unit is such as to close the valve controlling that port, the exhaust steam delivered by the auxiliaries to the heater might be, and in general would be, insutlicient to heat the feed water to the desired temperature.

An object of this invention is, therefore, to produce new and improved apparatus for augmenting the exhaust steam supplied to the feed water heater or to any heating system by steam from the main power unit, and for delivering the excess steam from the heater or heating system to the main unit, in which means are employed for substantially maintaining a determined pressure within the heater or heating system regardless of the pressure conditions existing within working passages of the cotiperating main power unit.

A further object is to produce apparatus for bleeding augmenting fluid from a fluid actuated engine to a heating system or heater in which means are employed for automatically maintaining a desired pressure within the heating system or heater independently of the pressure conditions within the working passages of the engine.

A further object is to produce a valve mechanism for bleeding steam from a low pressure working passage of a power developing unit, and delivering it for heating or industrial purposes, in which means are employed for maintaining the steam pres sure delivered by this valve substantially constant independently of fluctuations of pressure in the low pressure working passage above the desired pressure of the steam delivered.

These and other objects, which will be made apparent throughout the further description of my invention, are accomplished by means of apparatus embodying the features herein described and illustrated in the drawing accompanying and forming a part hereof.

In the single sheet drawing I have illustrated in sectional view a valve mechanism forming an embodiment of my invention.

The valve mechanism illustrated includes a casing 5, provided with a port 6, adapted to communicate with a heater or other source of low pressure steam, and a port 7, adapted to communicate with a bleeder port provided in the working passages of a fluid actuated engine or turbine. As illustrated, communication between the ports 6 and 7 is controlled by two cylindrical valves or pistons 8 and 9, which are both subjected on one side to the pressure existing within the portion of the casing communicating with the port 6. The casing is divided by means of a diaphragm 11, shown in the drawing as more or less rectangular in shape, into two compartments or portions 6 and 7 the former communicating with the port 6 and the latter with the port 7. within which the piston 8 operates, is so formed within the casing that the lower face of the piston is subjected to the pressure of the fluid existing in the compartment 6, while the upper face is subjected to any constant pressure, as for example, atmospheric pressure, admitted through a port 13. Ports 14 are formed within the cylinder 12 and are adapted to be opened by, or to be placed in register with ports 15, formed in the piston 8, for certain positions of the piston. These ports 14 and 15 establish communication between the ports 6 and 7 when they are in register or when the ports 14: are opened or partially opened by the ports 15. A cylinder 16 is located within the casing 5, is alined with the cylinder 12, and is so located that its upper end, which is open, is in communication with the compartment 6, and its lower end, which is also open, is in communication with the compartment 7 The piston 9 operates within this cylinder and is provided with ports 17, which are adapted to move into register with or to uncover ports 18, formed within the cylinder 16, and to thereby establish communication between the ports 6 and 7.

The piston valve 8 is provided with a tubular rod or stem 19, which projects upwardly through the end of the casing and is provided, at a point outside of the casing, with a collar 21, which for certain positions of the piston is adapted to engage a movable and weighted stop 22, shown in the drawing as formed on a lever 23, to the free end of which a weight 24 is hung.

The piston valve 9 is provided with a stem 25 which extends upwardly through the casing, and through and beyond the hollow stem 19. The outer end of the stem 25 is provided with a collar 26, which is adapted to be engaged by the upper end of the stem 19 after the piston 8 has moved upwardly to fully open the ports 14. The stem 25 is also provided with a collar 27 which is adapted to engage the piston 8 after the piston 9 has been moved, independently of the piston 8, to fully open the ports 18.

Throughout the further description of the invention, I will consider, but for the pun pose of description only, that the illustrated embodiment is applied to an installation including a feed water heater, receiving steam from any more or less constant source of supply such as the exhausts of auxiliaries, and a turbine operating as the main power developing unit and having a bleeder port communicating with a stage in which the pressure under normal full load conditions approximates atmospheric pressure. I will also assume that at maximum overload conditions the pressure within the A cylinder 12,

working passage or stage of the turbine, communicating with the bleeder port, rises to approximately ten or fifteen pounds above atmosphere and that it is desirable to have the auxiliaries subjected to a back pressure not greater than five pounds above atmosphere. Let it also be assumed that the steam pressure in the heater is to be maintained at approximately atmospheric pressure during periods of normal load conditions on the turbine.

lVith the apparatus illustrated and with the port 13 open to the atmosphere, a rise in pressure within the heating system slightly above atmospheric pressure will lift the piston 8 so as to move the ports 15 into register with the ports 14. This will cause steam to be delivered from the heating system through the bleeder port into the working passage of the turbine. The unbalanced steam pressure on the piston 8 will move the piston upwardly until the collar 21 carried by its stem 19 contacts with the weighted stop 22. The collar 21 is preferably so located on the stem 19, with relation to the stop 22, that the ports 14: will be fully opened when the piston is checked by the stop If, now, the load on the turbine increases so that the pressure existing at the bleeder port of the turbine exceeds atmospheric pressure, a corresponding increase in pres sure will be occasioned in the heating systemby reason of the fact that the heating system is in open communication with the bleeder port. This increase in pressure will tend to cause the valve 8 to move upwardly to the end of its travel and to close the ports 14 by causing the ports 15 to move past them. This tendency, however, is resisted by the cooperation of the collar 21 with the movable stop 22, and also by reason of the fact that the weight of the piston 9 is also imposed on the piston 8 by the engagement of the end of the stem 19 with the collar 26 on the stem 25. The stop may be so weighted that the downward thrust imparted to the collar 21 will correspond to a fluid pressure of approximately five pounds per square inch on the piston 8, and, under such conditions, the ports 14 and 15 will remain in register until the pressure in the heating system slightly exceeds five pounds. The unbalanced fluid pressure on the piston 8 will then lift both the pistons 8 and 9 in opposition to the weight 24, will close the ports let, and will momentarily open and then close the ports 18. The valve will therefore be completely closed and the pressure in the turbine may reach any pressure above five pounds without in any way affecting the pressure in the heating system.

If, now the pressure in the heating system decreases, the piston 8 will move downwardly in response to a decreasing pressure within the casing compartment 6 and will.

again establish communication between the ports'6 and 7 by uncovering the ports 14. These ports, however, will immediately close as soon as the pressure within the heater again exceeds a pressure of five pounds. In this way the pressure in the heating system will be maintained at substantially five pounds above atmosphere, while the load conditions are such as to maintain at least that 'pressure at the bleeder port of the turbine.

If the pressure in the heating system and the pressure at the bleeder port of the turbine both decrease to approximately atmospheric pressure, both of the pistons 8 and 9 will move downwardly, first establishing communication between the ports 6 and 7 by opening the ports 14 and 18 and then closing the valve. If, under such conditions, the pressure in the heater continues to decrease by reason of the fact that the exhaust from the auxiliaries is insufficient, the pressure in the compartment 7 of the valve casing 5 will preponderate over the pressure in the compartment 6 and will lift the piston 9 thereby establishing communication between the turbine and the heater so that steam will pass through the bleeder port of the turbine and the valve to the heater. As the piston 9 moves upwardly in response to the preponderance of pressure at the port 7 over that existing at the port 6, the collar 27 carried by the stem 25 moves into contact with the piston 8 and either checks the upward motion of the piston 9 so as to hold its ports 17 in register with the ports 18, or lifts the piston 8 and places its ports 15 in register with the ports 1-1, thereby maintaining communication between the ports 7 and 6. The upward movement of the piston 8 in response to the preponderance of pressure acting on the piston 9 will be checked by the collar 21 engaging the movable stop 22 and the ports 15 of that piston will be held in register with the ports 14 until the pressure delivered through the port 7 exceeds five pounds above atmosphere, at which time the valve will. be closed by the upward motion of both pistons as has been previously described.

Turbines are ordinarily equipped with automatic stop governors which operate automatically to shutoff the delivery of steam to the turbine when it exceeds a safe or determined speed. In the drawings I have shown means adapted to operate in conjunction with such a governor for closing the valve independently of the pressures existing at either the ports 6 or 7 As illustrated, the means includes a cylinder 30, in which a piston 31 is located. The rod 32 of the piston is connected by means of a lost motion connection to a lever 34, which is pivoted at one end. on a link 35, and at the other end is provided with a bonnet 36,

which incloses the upper end of the stem 25, and is adapted to engage the upper end of the stem 19. A steam inlet port 37 is formed in the cylinder 30 above the piston, and a discharge port 38 is formed in the cylinder below the piston. The piston is so formed that steam will leak around it and equalize the pressure on both sides of it when the port 38 is closed. Under such conditions the piston will normally be held in a raised position and will thereby permit the bonnet 36 to move up and down with either the stem 19 or the stem 25 of the respective pistons S and 9. This is due to the fact that the area of the piston subjected to the pressure of the steam in the lower end of the cylinder is greater than that subjected to the pressure of the steam in the upper end of the cylinder. hen the exhaust port is opened and placed in communication with either the atmosphere or the condenser serving the turbine, steam will not leak around the piston in sufficient quantities to counterbalance the steam pressure above the piston and consequently the piston will be moved to the lower end of its stroke and in so moving will force both of the pistons 8 and 9 to the lower ends of their stroke through the agency of the bonnet 36. The exhaust port 38 is controlled by a valve, not shown, which in turn is controlled or adapted to be opened by the automatic stop governor.

It will be apparent, from this description of the illustrated embodiment of my invention, that the pressure in the heater will always be maintained at the desired pressure independently of the pressures encountered within the working passages of the turbine or unit and that an excessive pressure of the steam at the bleeder port of the power unit will not prevent the valve mechanism from operating to bleed steam from the power unit to the heating system. It will also be apparent that a valve mechanism embodying my invention may be employed for bleeding steam from the power unit for industrial purposes, or for a heater when all the steam received by the heater or other apparatus communicating with the bleeder port is supplied from the power unit, and that various changes, modifications, additions, omissions and substitutions may be made in the apparatus illustrated without departing from the spirit and scope of the invention as set forth by the appended claims.

lVhat I claim is:

1. A valve mechanism for bleeding fluid from a power developing unit and for delivering fluid to said unit from a low pressure source of supply, comprising means responsive to the pressure of fluid from a low pressure source of supply for delivering fluid from said source to the power unit and means responsive to the diflerence in pressure between fluid from said low pressure source and the fluid pressure in said power developing unit for bleeding fluid from the power unit to the source of low pressure supply.

2. A valve mechanism for bleeding fluid from apower developing unit and for delivering fluid to a low pressure working passage of the unit from a low pressure source of supply, comprising means responsive to the pressure of fluid from a low pressure source of supply for establishing communication between the source and a low pressure working passage of the power developing unit independently of fluctuations in pressure within the working passage above a determined pressure and for cutting oflt communication between the source and the unit when the pressure at the source exceeds a determined pressure.

3. A valve mechanism for delivering fluid from a low pressure source of supply to a low pressure working passage of a power developing unit, comprising means responsive to pressure of fluid from the source for delivering fluid from the source to the power developing unit, and for closing communication between the source and the unit when the pressure in the low pressure passage of the source exceeds a determined pressure, and means, partially dependent on the operation of said first mentioned means and responsive to variations in the difference in pressure between fluid from said source and fluid from the low pressure working passage of the unit for delivering fluid from the unit to the source independently of the variations in pressure of the fluid in the low pressure working passage of the source above the determined pressure.

l. In a valve mechanism for bleeding fluid from a working passage of a power developing unit and for delivering fluid to the working passage of the unit from a low pressure source of supply, a valve casing having a port adapted to communicate with a low pressure source of fluid supply, and a port adapted to communicate with a fluid passage of the power developing unit, and means for controlling communication between said ports, responsive in operation to the difference in pressure between fluid from the low pressure source and fluid from the fluid passage of the unit.

5. A valve mechanism, comprising a valve casing having a port adapted to communicate with a source of low pressure fluid supply, and a second port adapted to communicate with a low pressure'passage of a power developing unit, a valve responsive to the pressure of fluid at said first mentioned port for controlling communication between said ports, and a second valve responsive to variations in the difference in pressure of the fluid existing at said ports for controlling communication between said ports independently of said first mentioned valve.

6. A valve mechanism comprising a casing having two ports through both of which fluid is at times adapted to be received and delivered, a valve within the casing responsive to the difference in fluid pressure existing at each port for establishing communication between said ports and means controlling the operation of said valve to close communication between said ports when the pressure delivered from the one port to the other exceeds a determined pressure.

7 A valve mechanism comprising a casing having two ports through both of which fluid is at times adapted to be received and delivered, a valve within the casing responsive to the difference in fluid pressure existing at each port for establishing communication between said ports, means controlling the operation of said valve to close communication between said ports when the pressure delivered from the one port to the other exceeds a determined pressure, and a second valve responsive to the fluid pressure at one of said ports for establishing communication between the ports, and for actuating said first mentioned valve.

8. A valve mechanism comprising a casing having two ports through both of which fluid is at times adapted to be both received and delivered, a valve located within said casing and responsive in operation to the preponderance in fluid pressure at one port over the fluid pressure existing at the other for establishin communication between said ports, a second valve located within the casing and responsive to the pressure at one of said ports independently of the pressure existing at the other port for establishing communication between said ports.

9. A valve mechanism comprising a casing having a port adapted to communicate with a low pressure source of fluid supply, and a port adapted to communicate with a power developing unit, a valve within the casing responsive to the preponderance in pressure of the fluid existing at the last mentioned port over that existing at the first mentioned port for establishing communication between said ports, and means responsive to the fluid pressure at the first mentioned port for closing communication between said ports when the pressure at the first mentioned port exceeds a determined pressure.

10. A valve mechanism comprising a casing having a port adapted to communicate with a low pressure source of fluid supply, and a second port adapted to communicate with a low pressure passage of a power developing unit, and means located within said casing and responsive to the preponderance of pressure of the fluid at the second port over the pressure of the fluid at the first mentioned port for establishing communication between said ports when the fluid pressure at the second port exceeds that at the first mentioned port and for closing communication between the ports when the fluid pressure at the first mentioned port exceeds a certain determined pressure.

11. A valve mechanism, comprising a casing having a port adapted to communicate with a source of low pressure fluid, and a second port adapted to communicate with a low pressure passage of a power developing unit, and means located within the casing and responsive to the preponderance of fluid pressure at said second port over the pressure existing at the first port for establishing communication between said ports when the pressure at the second port exceeds the pressure at the first port and for closing communication between said ports when the pressure at the first port exceeds a determined pressure.

12. A valve mechanism comprising a casing having a port adapted to communicate with a source of low pressure fluid supply, and a second port adapted to communicate with a low pressure passage of a power developing unit, a valve within the casing responsive to the preponderance of pressure at the second port over that at the first mentioned port for establishing communication between said ports when the pressure at the second port exceeds that at the first mentioned port and for closing communication between said ports when the pressure at the first mentioned port exceeds a determined pressure, and a second valve responsive to the pressure at the first mentioned port, and independent of the pressure at the second port for e'stablishing'communication between the ports when the pressure at the first mentioned port reaches an established pressure.

13. A valve mechanism comprising a casing having a port adapted to communicate with a source of low pressure fluid, and a second port adapted to communicate with a working passage of a power developing unit, a valve responsive to the pressure existing at the first port for establishing communication between said ports when the pressure at the first port reaches an established pressure and for shutting ofl communication between said ports when the pressure at the first port exceeds a determined pressure, and a sec ond valve located within the casing responsive to a preponderance in the pressure at the second port over the pressure at the first port for establishing communication between said ports independently of the first mentioned valve.

, 14. In a valve mechanism for bleeding fluid from a working passage of a power developing unit and for delivering fluid to the working passage of the unit from a low pressure source of supply, means responsive to Variations in the pressures at the source and in the working passage of the unit for controlling the operation of the valve mechanism and means independent of said pressures for closing said valve mechanism.

15. In a valve mechanism for bleeding fluid from a working passage of a power developing unit and for delivering fluid to the working passage of the unit from said source, means responsive to the pressure at said source for establishing communication between the source and the unit,'means responsive to the pressure in the unit for establishing communication between the source and the unit when the pressure at the pressures for closing communication be tween the source and the unit.

In testimony whereof, I have hereunto subscribed my name this 15t day of May, 1915.

FRANCIS HODGKINSON.

Witnesses:

C. W. MoGI-IEE, E. W. MoCALLIsTER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). C.

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