US1267386A - Heat-balance duplex-drive. - Google Patents

Description

D. K. DEAN.

HEAT BALANCE DUPLEX DRIVE.

APPLICATION FILED JAN-25,1917. RENEWED MAR. 19.1918.

Patented May 28,1918.

H l/VVE/VTOR 0% 4 /,C Q aid 4% ATTORNEY UNITED STATES. PATENT OFFICE.

DION K. DEAN, OF 'WINTHROP, MASSACHUSETTS, ASSIGNOR TO ALBERGER PUMP AND CONDENSER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

HEAT-BALANCE DUPLEX-DRIVE.

Specificationof Letters Patent.

Patented May 28, 1918.

Application filed January 25, 1917, Serial No. 144,375. Renewed March 19, 1918. Serial No. 228,468.

To all whom it may concern:

Be it known that I, DION K. DEAN,a citizen of the United States, and resident of Winthrop, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Heat- Balance Duplex-Drives, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to a heat balance duplex drive. In the operation of certain kinds of steam power plants, the maximum plant economy with a given set of apparatus is securedwhen certain machines, such as the ordinary plant auxiliaries, are driven by steam, providing that the amount of such steam when passing from the machines in the form of exhaust steam does not exceed that which is required in the plant for proper use in heating feed water or performing other heating work.

Among many objects which might be mentioned as the object of the invention, I indicate that my invention will improve the operation of steam turbine driven machines in a three-fold way; first: to automatically supply an amount of driving steam, which when exhausted will be proper and adequate to perform the further useful purposes of such exhaust steam; second: to automati cally guard against supplying an amount of driving steam, which when exhausted would be in excess of the requirements for such exhaust steam; and third: to provide fOr the driven machine a duplex drive from two sources of power, so that in the event of the failure of one of these power sources, the other will automatically assume the proper operation of the machine.

In case the power requirements of the plant auxiliaries at any given time should demand more steam than when exhausted would properly take care of the stated heating or other requirements for the use of such exhaust steam, it would be more economical to carry a portion of the auxiliary load by means of an electric motor,which receives its current from the main unit, so as to reduce the quantity of exhaust steam to that required for the further useful purposesof such exhaust steam, inasmuch as such a drive would give the auxiliaries the benefit of approximately the steam rate of the main unit for that portion of the load carried by the electric motor. Since it results that a maximum of economy and safety cannot possibly be secured by manual operation, automatic control is rendered extremely advantageous. It is to be recognized moreover that the accidental stoppage of any of the machines of the power plant involves serious consequences, and hence, an auxiliary source of power which is instantly available and is automatically brought into action is made very desirable. The invention, therefore, may be said to consist essentially in the heat balance drive capable of automatically securing the results mentioned, and in various details and peculiarities in the combination, construction, and arrangement of the various parts, substantially as will be hereinafter described and then more particularly pointed out in the claims.

In the accompanying drawing illustrating my invention:

Figure 1 is a side elevation of a power plant arrangement, including therewith the features of my improved heat balance duplex drive.

Fig. 2 is a right hand end elevation of the same.

Fig. 3 is'an enlarged sectional detail of the pressure and the speed governor mechanism.

Similar characters of reference designate corresponding parts throughout the different figures of the drawing.

1 denotes a driven machine, which may be any kind of a machine, such for example, as a power plant auxiliary mechanism, a pump, or any other kind of machinery. 2 denotes an electric motor, and 3 a steam turbine, both of which are connected by suitable shafting and flexible couplings or other means with the driven machine 1 so that either the electric motor or the steam turbine may drive said machine, or either one may vdrive the rotor of the other in case the other is not in operation. While in the arrangement illustrated in the drawings the shafts of the machines 1, 2 and 3 are directly connected together, it is obvious that they may be geared or otherwise connected so as to rotate in unison; further, it will be noted that it is sometimes pos sible that the speed of the" driven machine would not be suitable for direct connection to the turbine or the motor, in which case the shaft of the machine and the shaft of either or both of the other elements might easily be connected through a set of speed reduction gears whereby the required results would be efi'ectively obtained. It will be uhderstood that the rotor of one element will drive the idle rotor of the other element, for if one end of the shaft, which for operative purposes may be considered as solidly connected to the other end of the shaft,

v is driven, for example, by the motor rotor at one end of the shaft while steam is not being admitted to the turbine rotor, the work necessary to drive that turbine rotor must necessarily be done by the motor rotor; or as the rotors of all the elements may be viewed as part of the shaft, those rotors are driven which do not receive some impelling force of energy such as electric current in the case of an electric motor, and steam in the case of a turbine, and that rotor is the driver which does receive for the time being the outside impelling source of energy. Obviously there may be some cases where two elements could be drivers simultaneously, but it is unnecessary to enlarge upon these features.

The electric motor 2 is properly, located and arranged and connected electrically with a suitable source of electric energy so as to operate therefrom; while steam is admitted to the steam turbine 3- through a steam supply line 4. The exhaust steam from the steam turbine 3 is led away through the exhaust line or conduit 5. The admission of the steam to the turbine through the line 4 is controlled in the first instance by a pressure governor which operates a valve 6 situated at a suitable point in the length of the pipe 4, as-shown. T will now explain one specific example of a pressure governor which may be used for the purpose l have in view, although 1 do not wish to be confined to this form of pressure governor as it is an example merely and a great many other kinds may be substituted in lieu of the same for doing the same work. In Figs. 1 and 3 the valve 6 is seen to be carried by a stem 7 running upwardly through guides at 8, and being attached to a diaphragm 9 which forms one side of a pressure chamber 10, said chamber being supported on any suitable frame Work 11. A spring 12 is tensioned between the guide 8 and the diaphragm 9 and serves to normally lift the valve 6 ofi' its seat so that the passageway through the pipe 4 will be normally open. The exhaust pipe 5 moreover connects by pipes 13 and 14 with the pressure chamber 10, so that the pressure until when the pressure rises high enough valve 6 Will be closed upon its seat and the passage of steam to the turbine 3 through line 4 will be cut ofi so long as the valve 6 remains closed. llt will be seen, however, that ordinarily the valve 6 is open and the same pressure will exist in chamber 10 that exists in the exhaust line 5. The tension of the spring 12 is so set that until a certain predetermined pressure in the exhaust line. 5 is reached, this overning mechanism,

as already stated, Wil keep valve 6 Wide open, but when a certain higher pressure is reached, valve 6 will be closed tightly and the valve will occupy intermediate positions with intermediate pressures. The

higher pressure at which the valve 6 is tightly closed by this pressure governor would correspond to the maximum desirable or preferred pressure of the exhaust steam for the heating or any other system in which the exhaust steam is utilized, such as would be determined by a pressure relief valve on this system or other equivalent means for determining pressure.

According to the mode of operation, therefore, of a pressure governor combined and related to the steam supply line and the steam exhaust line of a steam turbine, it will be understood that the amount of steam which is permitted to pass the valve6 by the action of the pressure governor will bear a definite relation to the pressure in the exhaust line 5, which latter pressure in its turn is dependent upon the requirements for exhaust steam in the heating or other system in which the exhaust steam is utilized.

To regulatethe speed of the driven rnachine 1 and to guard against overspeed, a speed governor is provided, which may be of any type, as for example, a centrifugal ball governor 15, which I have illustrated. This is driven by being connected with a worm 16 on'the main shaft 16 through a pinion 17 on a shaft 18 and beveled gears 19 and 20, the latter being loose on a vertical valve stem 21 which is supported in a fram 32 fixed upon the supply pipe 4, said stem21 being attached to the valve 22 operating in connection with seat 23 in the pipe 4. The

21 ample liberty to move up and down through it. If the speed of the driven machine 1 falls below that desired, then the centripetal action of the balls 24 will serve to open the valve 22 more widely so as to admit to the turbine 3 a greater quantity of the steam that is permitted to pass the pressure governor by reason of the pressure in the exhaust line 5; and conversely whenever the speed of the machine tends to exceed a proper predetermined speed, the action of the balls in flying outwardly will close the valve 22, or move it. closer to or seat it tightly upon its seat 23 and thus decrease or shut off the supply of the steam which is passing to the turbine through the supply line 4 under the regulation of the pressure governor.

When the supply of steam admitted to operate the turbine 3=becomes insufficient to carry the load at the predetermined operat ing speed by reason of the action of the pressure governor, the electric motor will of necessity and in an automatic manner take up the load in an effort to maintain the proper operating speed for the driven machine, and thus a duplex drive is provided.

In order to guard against a shut-down of the power plant auxiliaries due to a failure of the supply of electricity or to some injury to the motor, as may occasionally happen, at a time when the pressure from the exhaust line 5 is sufficiently high to cause the pressure governor to have its valve 6 tightly closed upon its seat so that no steam is being supplied to the steam turbine for the time being, I provide a relief or cut-off valve 28 of any suitable type or variety and of sufficient area Or capacity for the purpose, the same beingpreferably connected to the junction of the communicating pipes 13 and 14 between the exhaust line 5 and the pressure chamber 10 of the pressure governor. so that by the opening of said relief valve 28 which takes place automatically, the pressure which closes the valve 6 of the pressure governor is released, and said valt'e 6 opens and reestahlishes the supply of operating steam to the turbine, leaving said supply to be regulated for the time being by the action of the speed governor only.

Said relief or cutofi valve 28 is operated by means of a suitable mechanism acted upon by the speed governor at a time when the speed of the machine shall have dropped to a predetermined point, and as stated, the action of said valve 28 will cause the pressure in the chamber 10 to drop to that of the atmosphere so that the tension of the opening spring 12 will open the valve and allow steam to freely pass through the pipe 4:, except in so far as its passage is controlled by the action of the speed governor.

In the drawings I have illustrated a simple form of operating mechanism whereby the speed governor controls the opening of the relief valve 28, but it will be understood that I do not wish to be restricted thereto and have shown the same here simply by way of example in order to disclose a practical and successfully operative combination. A bell-crank lever 29 is pivoted at 30 on a bracket 31 carried by the frame of the turbine engine 3, one arm of said bell crank 29 lying in the vertical path of movement of the rising and falling traveler 27 of the ball governor 15, while the other arm of bell-crank 29 is in the form of a catch or latch at 33. The bell-crank 29 is provided with an adjustable screw or block device 34, the lower end of which is below the horizontal arm of bell-crank 29 and in a position to be struck by the traveler 27. By adjusting the screw or block 34 up or down it can be regulated so that the action of the bell crank when struck by the traveler will be properly timed. The catch 33 of bell-crank 29 normally engages a similar catch 35 forming part of a bell-crank 36 pivoted at 37 on the bracket 31, said bell-crank 36 having a weighted arm 40 which connects by means of a chain 38 with the operating lever 39 of the relief valve 28. It will be perceived that normally the engagement of the catch devices 33 and 35 will hold the bell-cranks in the position shown in Fig. 1, Where the weighted arm 40 is restrained from falling and pulling upon the chain 38 so as to open the relief valve 28, but when the bell-crank 29 is lifted by the action of the speed governor, and the catch'33 is set free from the catch 35 the weighted arm 40 will operate to open the relief valve 28.

If the speed of the unit drops, therefore, from any cause to a predetermined point, the traveler 27 of the speed governor 15 will rise to such a point as to engage the lower end of the adjustable screw or block 34, rotate the bell-crank 29 far enough to disengage the catch devices 33 and 35, and permit the unbalanced weighted arm 40 to rotate the latter around its pivot 37 and open the relief valve 28 through the connection 38. As I have said, it is obvious that the adjustment of the device 31 will allow the traveler 27 to engage the same at any speed desired. Although I have shown this particular mechanism for operating the relief valve, yet it is only one of many which might be used, and it will be understood that the mechanism may be of any type suitable for the purpose.

A desirable feature. and one which I find can be used effectively, is a small steam pipe 50 having therein by-pass valve 51, which would permit a sufficient amount of steam to flow past the two valves to keep the turbine casing at a proper temperature for instant operation. The amount of steam passing through this by-pass valve 51 would be very small, being insuflicient to operate the turbine proper, and only enough to keep the temperature practically constant, but it might be an essential feature of the operation, and l, therefore, describe it here as making for the best practice.

It will thus be seen that T have provided a heat balance duplex drive for pumps and other machinery which is very efiective and useful and which can easily attain the objects which I have in view. When the conditions arise, as stated, the members of the duplex drive are brought into operation, also, the serious results of any accidental stoppage are avoided, and there is an economy in the consumption and use of the steam, so thatin fact the whole combination is productive of useful and valuable results.

lln order to more fully explain the operation, I will illustrate by concrete example of how the load is balanced between the two elements. Suppose that the driven machine is a centrifugal pump with an allowable operating speed of between 1760 and 1800 R. P. M. The motor will be an induction motor connected to a 60 cycle circuit, and will have a no-load operating speed of 1800 it. P. M. The turbine speed governor will be set so that when the pressure governor is wide open and the turbine is carrying a full maximum load, namely, running the machine and the idle rotor of the motor, this turbine will run the machine at a speed of 1800 R. P. M.

Let us suppose that it is desired to use the exhaust steam in a feed water heating system under a pressure which does not exceed 3 pounds per square inch gage. This pressure could be kc t from exceeding this amount by means 0 a relief valve on the feed water heater or some other part of the system. The tension device on the pressure governor will be set so that the pressure governor valve will be completely closed when the pressure in the exhaust line rises to 3 pounds per square inch gage, but this Valve will be wide open when the pressure is only 2 pounds per square inch gage. We will assume the machine is running in this way and that because of the fact that for some reason there may be a surplus amount of steam in the feed water heating system, the pressure in this system and the turbine exhaust line would rise until it reaches 2 pounds per square inch gage at which time the pressure governor valve starts to close; as this starts to close the speed of the unit would fall slightly because the turbine would not be receiving enough steam to operate the unit at the fullspeed. llt is one of the principles-of operation of an induction motor that when it is connected to an electric circuit and receives its excitation from a generator with which it is in synchronism that if the speed of that motor is slowed down from any cause, such as the application of some force to the rotor, the motor will convert electrical energy into mechanical energy in an efi'ort to overcome the force which has caused it to slow down below the synchronous no-load operating speed. Since the reduction of the amount of steam admitted to the turbine would tend to slow down the whole unit including the motor, this motor will automatically assume part of the load at the speed resultin from the decrease in the steam supply. f the pressure in the exhaust line rises to 3 pounds per square inch gage the pressure overnor valve will be closed completely an the entire load including that necessary to run the turbine rotor will be assumed by the motor. If the pressure in the exhaust line falls below 3 pounds per square inch, steam will be admitted to the turbine and part of the load will automatically be assumed by it.

If the pressure continues to fall, more and more of the load will be carried by the turbine until the pressure drops to 2 pounds per square inch gage at which point the pressure overnor valve will be wide open. The spee governor will admit all the steam necessary to maintain a speed of 1800 R. P. M., which speed is the no-load synchronous speed of the motor, at which speed it cannot deliver power to the shaft of the machine, or in other words, under this condition the turbine would be carrying the full load.

Many changes may be made in the precise construction, combination, and arrangement of the specific elements in their relation to each other for attaining the objects in view, and T, therefore, reserve the liberty of making all such changes as experience may indicate to be wise and practical.

Having thus described my invention, what ll claim as new and desire to secure by Letters Patent is 1. Tn a heat balance duplex drive, the com-' bination of a machine, an electric motor and a steam turbine arranged to drive the machine singly or together, and either operative to drive the rotor of the other when the latter is idle, a steam supply for the turbine and an exhaust for the same, and a pressure governor responsive to the variations of pressure in the exhaust, and a valve for relieving the pressure at certain times in the pressure governor, together with means for operating said relief valve.

2. The combination of a driven machine, a motor for driving it, a steam turbine for likewise driving the machine, means for permitting said motor and turbine to operate jointly or singly, and either to drive the rotor of the other when the latter is inoperative, a steam supply line for the turbine, a steam exhaust line for the turbine, a pressure governor, means for connecting the exhaust line to the supply line, in which means the pressure governor is located so as to be responsive to the variations of pressure in the exhaust line, and control the admision of steam to the turbine from the steam supply line, together with a relief valve arranged in connection with the pressure governor for rendering the latter unresponsive at times to variations of pressure in the steam exhaust line.

3. The combination of a machine, an electric motor and a steam turbine both arranged to drive the same singly or jointly, and either operative to drive the rotor of the other when the latter is idle, a steam supply line to and a steam exhaust line from the turbine, a pressure governor responsive to the variations of pressure in the exhaust line controlling the amount of steam admitted through the supply line, a speed governor, and means whereby said governor serves as a secondary control for the admission of steam through the supply line, to-

gether with a valve for relieving the pressure at certain times in the pressure governor, and means for operating said relief valve. I

4. The combination of a machine, a motor and a turbine for driving the same jointly or singly, means for supplying steam to the turbine, means for exhausting steam therefrom, means for connecting the exhaust and the supply, a pressure governor arranged in connection with the latter means and responsive to the variations of pressure in the exhaust for the purpose of controlling the quantity of steam admitted through the supply, a speed governor controlling the admission of such steam as is permitted to pass the pressure governor, said speed governors serving as a secondary control for the admission of steam through the supply line, together with a relief valve arranged in connection with the pressure governor for rendering the latter unresponsive at times to variations of pressure in the steam exhaust line.

5. The combination of a machine, an electric motor and a steam turbine, each serving to drive the machine when operatin singly or when operating together, and eit er 0perative to drive the rotor of the other when idle, a steam supply line to and a steam exhaust line from the turbine, a pressure governor responsive to the variations of pressure in the exhaust controlling the quantity of steam admitted through thesupply, a speed governor responsive to the speed of the driven machine and serving as a secondary control for the admission of steam through the sup ly line, and a relief or cutofi valve for re ieving the pressure in the pressure governor and operated by the speed a governor.

6. The combination of a machine, an electrio motor and a steam turbine, each serving to drive the machine when operating singly or when operating together, and either operative to drive the rotor of the other when the latter is idle, a steam supply line and a steam exhaust line from the turbine, a pressure governor responsive to the variations of pressure in the exhaust controlling the quantity of steam admitted through the supply, a speed governor responsive to the speed of the driven machine servin as a secondary control for the admission 0 steam through the supply line, means for connecting the steam exhaust line and the pressure governor, a pressure relief valve arran ed in connection with said means for ren ering the pressure governor unresponsive to variations of pressure in the steam exhaust line, and a mechanism actuated by the speed governor when the machine is running at a predetermined speed for operating the pressure relief valve.

7 The combination with a driven element, and motor devices for driving the same singly or together, of a steam supply for one of the motors and an exhaust for the same,a pressure governor responsive to the variations of pressure in the exhaust, and a relief valve for relieving the pressure in the pressure governor, together with means for automatically operating said relief valve.

8. In a heat balance drive, the combination of a driven machine, motors for operating the same singly or together and either operative to drive the rotor of the other when the latter is idle, a steam supply for one of said motors and an exhaust for the same, a pressure governor responsive to the variations of pressure in the exhaust, a speed governor responsive to the speed of the driven machine and acting as a secondary control for the admission of steam through the supply line, and a valve for relieving the pressure in the pressure governor, said valve being operated by the speed governor.

9. The combination of a driven element, motors for actuating the same, each serving to drive the machine when operating singly or together and either operative to drive the rotor of the other when idle, a steam supply line and a steam exhaust line for one of said motors, a pressure governor connected to the exhaust line and controlling the quantity of steam admitted through the supply, a speed governor acting as a secondary control for the admission of steam, and a valve for relieving the pressure in the pressure governor.

1.0. The combination of a machine, a plurality of means for actuating the same, each serving. to drive the machine when 0 eratin singly or together, a steam supply ine an a steam exhaust line for-one of said operating means, a pressure governor connected with the exhaust, a speed governor respone V Leeneee sive to the speed of the driven machine and speed governor when the machine is running serving as a secondary control for the adat a predetermined speed for operating the mission of steam through the supply line, pressure relief valve. 1 means for connecting the steam exhaust line In testimony whereof I hereunto afix my 5 and the pressure governor, a pressure relief signature.

valve arranged in connection with said means, and a mechanism actuated by the DMDN K. DEAN,

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