US2436442A

US2436442A - Pump control system

Info

Publication number: US2436442A
Application number: US677607A
Authority: US
Inventors: Theodore C M Mauch
Original assignee: MORGAN SMITH S CO
Current assignee: MORGAN SMITH S CO; S MORGAN SMITH Co
Priority date: 1946-06-18
Filing date: 1946-06-18
Publication date: 1948-02-24
Anticipated expiration: 1965-02-24

Description

Filed June 18, 1946 Patented Feb. 24, 1948 UNITED STATES PATENT OFFICE PUMP CONTROL SYSTEM Application June 18, 1946, Serial No. 677,607

8 Claims.

This invention relates to new and useful improvements in control mechanisms for turbine driven machines, and more particularly to mech anisms for controlling operation of check valves in the discharge lines of turbine driven centrifugal pumps.

Valves of this type generally are employed in centrifugal pump installations where it is necessary to check reverse flow through the pump, for example, where centrifugal pumps are used to deliver water against pressure to a main or to a storage reservoir. Such centrifugal pump installations quite often are driven by means of steam turbines and if for any reason the steam pressure supply to the turbine should fail or drop materially and reverse flow set in then the centrifugal pump acts as a turbine to drive the steam turbine in the reverse direction with probable resulting damage and injury to the turbine.

It is highly desirable therefore to prevent reverse flow through the pump by closing the check valve to prevent reverse flow, and the object of the present invention is to provide a novel control mechanism or system which is operable automatically under predetermined conditions to close the check valve in the pump discharge line before reverse flow sets in.

Another object of the invention is to provide a novel control mechanism of the stated character which is operable in response to variations in the pressure of the steam supplied to the turbine to drive the same.

A further object of the invention is to provide a novel control having the features and characteristics set forth which is highly effective and foolproof in operation and use.

These and other obiects of the invention and the various features and details of the construction and operation thereof are hereinafter fullv set forth and described with reference to the accompeny ng drawing in which the single figure is a diagrammatic showing of a steam turb ne dri en centrifugal pump installation embodying a check valve control mechanism in accordan e with the present invention.

Referring no more particularly to the drau ing, reference numeral 1 designates a centrifu al pump to which ar c nnected the customary intake and

discharge lines

2 and 3 respect vel Connected in the pump discharge line 3 adiacent the pump l is a valve 4 which is operable und r certain conditions, hereinafter more fully e plained. to close the discharge line 3 and therehv preclude reverse flow through the pump ll Preferably the valve 4 is of the well-known fourway hydraulic piston operated type controlled, in the present instance, by means of a pilot valve 5 which is actuated by means of a solenoid device B.

In the illustrated embodiment of the invention, the construction and arrangement of the check valve 4 is such that when the solenoid i is energized the said valve 4 is fully open to permit flow through the line 8, and upon de-energization of the solenoid B said valve I is closed to preclude flow through the discharge line 3. Electrical conductors l and 8 lead from suitable line conductors 9 and Ill, respectively, to the solenoid device 6 and energization of the latter to operate pilot valve 5, and thereby the check valve 4 in the pump discharge line 3, is effected by means of a pressure operated electric switch II which is connected in series with the said conductors l and B. In the illustrated embodiment of the present invention the contacts of the switch H normally are held in closed circuit relation as shown, by means of a pressure responsive bellows or diaphragm device l2.

The centrifugal pump l is rotationally driven by means of a conventional type steam turbine l3 which is coupled to the shaft ll of said pump through suitable reduction gearing. The turbine 13 in turn is rotationally driven by steam supplied to said turbine 13 at a predetermined pressure through a steam line l5 having a suitable control valve l6 therein. and according to the present invention the bellows or diaphragm I2 is adapted to be operated to control the switch H in response to a predetermined steam pressure condition existing at any time in the line 15 between the turbine l3 and the control valve l6 therefor.

To this end, therefore, the interior of the bellows or diaphragm I2 is connected by means of a pipe or tube l! to the interior of a chamber H3 at the bottom thereof. and an intermediate portion of this pipe or tube I1 is suitably coiled, for example, as indicated. to provide a cooling coil or condenser l9 between the chamber l8 and the bellows or diaphragm I! of the switch II. A similar nine or tu e 20 leads from the interior of the chamber l8 at the too thereof and has its other end connected into the steam line l5 between the turbine l3 and its control valve 16, while an intake pipe or tube 2|, having an inwardly opening one-way check valve 22 therein. leads into the chamber l8 at the top thereof and has its other end open to the atmosphere as shown.

The bellows or diaphragm I! of the switch H thus is subjected to the pressure of the steam in the steam line I leading to the turbine I3 between the latter and the control valve 16, and the bellows of diaphragm I2 isconstructed and calibrated to effect opening of the switch II to break the electrical circuit to the solenoid B when the said steam pressure in line I5 falls below a predetermined value as hereinafter descri ed.

The cooling coil or condenser I8 provided in the pipe or tu e I'l functions to condense steam' flowing through the pipe or tube H from the line I5 toward the bellows or diaphragm I2 and the switch I I so that the steam does not reach thesee mechanisms and they are not subjected to the high temperature of the steam and heated the'm anism or system for steam turbine driven centrifugal pump installations which is operable automatically under predetermined conditions to close the check valve in the pump discharge line before reverse flow sets in. The invention also provides a control mechanism of the stated character which operates in response to variations in' the pressure in the stem Supply tothe turbine to drive the same; and'which is highly effective and foolproof in operation and use.

While a particular embodiment of the present invention has been illustrated and described herein, it is not intended to limit the invention to such disclosure, and changes and modificaby to an extent that may cause damage" or dis iitionsmay be made-therein and thereto within the rupt the calibration or settings thereof andof" other devices and controls that may bernountedi upon the same control'panel or board as the swi ch II. Excess condensate formed in'the' coil" or condenser I9 drains-or flows into the chamber I8.

lh the case of a: complete-failureprshut dovm ofthe steam supply in-the'li e IE -tothe turbine I3. the pre sure in the line I5 between the'va'ive I6 and turbine I! freuuently'is reduced to a m ne below' atmospheri'c pressure' thereby producin a; suction force in-the-pipe-Mandchain her I 8 whicli t'ends to withdraw the condensate from the chamber lfa'nd thepipe IT. It is highly desirable that provision bemade toprevent wit drawal of" the water-condensatefrom the chamber IWand-tlie tube or pipe I! insuch cases and. in the present instance, this is ac compli'shed by the provision of'the aforesaid in take pipe or'tube-ZI and'one-way check valve lf'which operateto" admit atmospheric air into the c amber lB"'so that the suctionforce' in tlie tube 2|! and chamber IB mereiy draws air' from the atmosphere inwardly throughthe pipe 21 and chamber l8to the turbine I3without disturbing the water condensateinsaid chamber' i B" and the pipe ortube I1.

In operation of the system and assuming: forpurposes of illustration only; that-thenormal operating steam pressure in the supply line I5 to the'turbine I3'-is l5o'pounds' gauge and that the switch actuating bellows or'diaphragm I2 "is 'con structed and arrangedto' hold the switch II closed under such normal operating conditions and to open said switch, inthe event that the steam pressure in the-line ii'falls below say, 80 pounds gauge, it will be'apparentlfromthe foregoingdescriptionthat upontfailure of the steam pressure orupon shut down'through operation the throttle I6, the steam pressure supply to the turbine in the line I5 almost'instantly will? fall below the 80 pounds setting of the Bellows or'diaphragm'fl; causing the latter to opewthe switch: I l'thereby deenergizing the sole noid'B to actuate the pilotzvalve 5 and cause the checkvalve 4 to close'and prevent reverse flow from the line 3 through the centrifugal. pump I: In addition; it is to be notedthat instarting operation of'tlie' pump" system, as the steam throttle I6 is* opened to warm the turbine I3 theinitial pressure will be veri low but as the turbine speed is brought up to approach the normal pumping speed a pressure of approximately 80 poundsgauge is reached thereby causmg the bellows or diaphragm I2 to close the switch II resulting in energization of the solenoidii and consequent operation of the pilot valve 5 to open the check valve 4,

From' the foregoing it will be seen that the present invention provides a novel control mechscopeof the claims.

Iclaim:

1. In a pumping system, a centrifugal pump having inlet and discharge pipes, a steam turbine operatively connected to said pump to drive the same, a steamsupply'lineeto'saiditurbine, a check valve in the pumpidischargerpipe normally open during operation ofithe= pumpingsystem, valve operating mechanism:includingppressure responsive means constructedi and: arranged to effect closing of said check valve upon the pressure in said steam" supply-linei failingrbeidw apredetermined value; a pressure line connecting from said steam'supply line tozsaid-pressure responsive means, a cooling'coillin saidrpressure line for condensing steam' therein; a closed chamber in said pressure line intermediate the steam'supply line and saidcoolingicoil to'recelve excess condensate from-the latter, and-means connecting the interior of said chamber to the atmosphere operable in the event ofgslib-atmosgiheric pressure in the'stea-m supply'line to prevent withdrawal of the condensate-fromsaidchamber andcooling coil.

2. In a pumping system; arcentrifugal pump having inlet and discharge pipes, a steam turbine operativelyconnected to said'pump to drive the same, a steamsupply line to said turbine, a throttle valve in said-,line tocontrol thesupply of steam to said'turbine, aichecic valve in the pump dischargepipe normally open during operation of the pumping system; valve operating mechanism including pressure responsive means constructed and-arranged to efiect closing of said check valve upon the pressurein saidsteam line betweenthe throttle and the turbine falling below a predetermined value, and a pressure line connecting to said pressure responsive means from said steamsupply line betweenthe-turbine and the throttle therein;

3. In a pumping system,- a centrifugal pump having inlet and discharge pipes, a steam turbine operativelyconnected to'said pump to drive the same, a steam supply line to said turbine, a throttle valve in said line to control the supply of steam to said turbine, a check valve in the pump discharge pipenormally open during operation of the pumping system, valve operating mechanism including pressure responsive means constructed and arranged to effect closing of said check valve upon the: pressure in said steam line between the throttle and the turbine falling below a predetermined value, a pressure line connecting to said pressure responsive meansfrom said steam supply line between the turbine and the throttle therein, a cooling coil insaid pressure line for condensing steam therein, a closed chamber in said pressure line intermediate the steam supply line and said cooling coil to receive excess condensate from the latter, and means connectin the interior of said chamber to the atmosphere operable in the event of sub-atmospheric pressure in the steam supply line to prevent withdrawal of the condensate from said chamber and cooling coil.

4. In a pumping system, a centrifugal pump having inlet and discharge pipes, a steam turbine operatively connected to said pump to drive the same, a steam supply line to said turbine, a check valve in the pump discharge pipe normally open during operation of the pumping system, means to operate said valve including a solenoid, an electrical circuit to energize said solenoid, normally closed switch means in said electrical circuit. pressure responsive means to actuate said switch means constructed and arranged to open said switch means and thereby close said check valve upon the pressure in said steam line falling below a predetermined value.

5. In a pumping system, a centrifugal pump having inlet and discharge pipes, a steam turbine operatively connected to said pump to drive the same, a steam supply line to said turbine, a check valve in the pump discharge pipe normally open during operation of the pumping system, means to operate said valve including a solenoid, an electrical circuit to energize said solenoid, normall closed switch means in said electrical circuit, pressure responsive means to actuate said switch means, a pressure line connecting from said pressure responsive means to said steam supply line and subjecting said pressure responsive means to the pressure in said steam line, said pressure responsive means being constructed and arranged to open said switch means and thereby close said check valve upon the pressure in said steam line falling below a predetermined pressure.

6. In a pumping system, a centrifugal pump having inlet and discharge pipes, a steam turbine operatively connected to said pump to drive the same, a steam supply line to said turbine, a check valve in the pump discharge pipe normally open during operation of the pumping system, means to operate said valve including a solenoid, an electrical circuit to energize said solenoid, normally closed switch means in said electrical circuit, pressure responsive means to actuate said switch means, a pressure line connecting from said pressure responsive means to said steam supply line and subjecting said pressure responsive means to the pressure in said steam line. said pressure responsive means being constructed and arranged to open said switch means and thereby close said check valve upon the pressure in said steam line falling below a predetermined pressure, a cooling coil in said pressure line for condensing steam therein, a closed chamber in said pressure line intermediate said cooling coil and the steam supply line to receive excess condensate from said cooling coil, and means connecting the interior of said chamber to the atmosphere operable in the event or sub-atmospheric pressure in the steam supply line to prevent withdrawal of the condensate from said chamber and cooling coil.

7. In a pumping system, a centrifugal pump having inlet and discharge pipes, a steam turbine operatively connected to said pump to drive the same, a steam supply line to said turbine, a throttle valve in said line to control the supply of steam to said turbine, a check valve in the pump discharge pipe normally open during operation of the pumping system, means to operate said valve including a solenoid, an electrical circuit to energize said solenoid, normally closed switch means in said electrical circuit, pressure responsive means to actuate said switch means, a pressure line connecting from said pressure responsive means to said steam supply line between the turbine and throttle to subject said pressure responsive means to the pressure in said steam line, said pressure responsive means being constructed and arranged to open said switch means and thereby close said check valve upon the pressure in said steam line falling below a predetermined pressure.

8. In a pumping system, a centrifugal pump having inlet and discharge pipes, a steam turbine operatively connected to said pump to drive the same, a steam supply line to said turbine, a throttle valve in said line to control the supply of steam to said turbine, a check valve in the pump discharge pipe normally open during operation of the pumping system, means to operate said valve including a solenoid, an electrical circuit to energize said solenoid, normally closed switch means in said electrical circuit, pressure responsive means to actuate said switch means, a pressure line connecting from said pressure responsive means to said steam supply line between the turbine and throttle to subject said pressure responsive means to the pressure in said steam line, said pressure responsive means being constructed and arranged to open said switch means and thereby close said check valve upon the pressure in said steam line falling below a predetermined pressure, a cooling coil in said pressure line for condensing steam therein, a closed chamber in said pressure line intermediate said cooling coil and the steam supply line to receive excess condensate from said cooling coil, and means connecting the interior of said chamber to the atmosphere operable in the event of sub-atmospheric pressure in the steam supply line to prevent withdrawal of the condensate from said chamber and cooling coil.

THEODORE C. M. MAUCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,980,374 Bradshaw Nov. 13, 1934 2,067,479 Dahlstrand et a1. Jan. 12, 1937 2,220,327 Goit et al. Nov. 5, 1940 2,384,420 Griswold Sept. 4, 1945