US2471596A - Pump - Google Patents

Description

May 31, 1949- J. c. WILLIAMS PUMP Filed April 4, 1945 Patented May 31, 1949 UNITED STATES OFFICE 1 Claim. 1

This invention, a pump, is specifically designed for use in oil cracking installations, though not restricted to such uses, since it is convertible to suit all types of breather, surging, and pumping requirements. Primarily this pump is designed to create surges of the hot oil in cracking columns, which surges are essential to high efficiency in cracking processes.

Centrifugal and other types of pumps have been tried for the purpose but have proven unsuitable to the task because of damage and deterioration created by the extremely hot .oil and the inability to create surges required for maximum efficiency.

Steam engines and reciprocating pumps in tandem are to a certain extent satisfactory except for the occasional shutdowns which are inevitable, sometimes because of leaky connections, lack of steam, or other causes. Reciprocating pumps operated by a motor through reduction gearing and a crank require too much space, and the motion is not very satisfactory because of gradual acceleration followed by gradual retardation. A uniform speed throughout each entire stroke is most satisfactory.

This invention provides a surge pump which drivesthe piston at a uniform speed throughout the length of each stroke with abrupt start and stop for each stroke, and intervening short total stop periods between strokes, thus providing the most advantageous surge conditions. It occupies a minimum of space and is economically constructed with a minimum number of parts, and simple operation.

This pump can be adjusted for straight pumping or direct fluid transfer, for surging alone, or for any combination of the two. Thus a surging operation can be accompanied by measured pumping to add to the fluid being surged, and the pumping may be confined to either stroke or endof the cylinder.

The objects and advantages of the invention are as follows:

First, to provide a pumping unit which is convertible at will for straight pumping, for surging, or for any combination thereof.

Second, to provide a pump as outlined in which one end of the pump can be used for straight pumping while the other end is used solely for surging a fluid.

Third, to provide a pump as outlined in which the relative proportions of fluid pumped and portions surged may be accurately controlled.

Fourth, to provide a pump as outlined with a new type of driving means, and which will drive the piston at a non-varying speed throughout the length of each stroke.

Fifth, to provide a pump as outlined in which a pair of cooperative threaded members in connection with reversing means is used for driving the piston.

Sixth, to provide a pump as outlined in which control means for reversing the direction of travel of the piston is controlled through members associated with the piston rod.

Seventh, to provide a pump as outlined which is simple in construction and operation and. which requires a minimum amount of space for installation and consists of a minimum number of parts.

In describing the invention reference will be made to the accompanying drawings, in which:

Fig. 1 is a top plan view of the invention with a portion shown in section and portions broken away to illustrate internal structures.

Fig. 2 is a side elevation of Fig. 1.

Fig. 3 is a vertical section through one of the intake valve housings.

Fig. 4 is a vertical section through one of the discharge valve housings.

The pump proper is interiorly of conventional reciprocating pump design, having a cylinder l0, cylinder heads H and I2, a piston l3, and an intake port I l and a discharge port l5 (Figs. 3 and l) at each end of the cylinder.

The invention resides in the specific new driving means for the piston, and in the Valves, valve adjustments and controls, and the manifold system, which permits the pump to be used for straight pumping, straight surging, or any combination of pumping or surging, for transfer from one or two sources and delivery to one or two destinations, or any combination thereof.

The invention principally resides in the method of driving the piston and the structures involved, through which the piston is driven at a uniform speed throughout the length of each stroke irrespective of the load, and in which cooperative threaded members reversible as to direction of' relative axial movement are employed.

These threaded members involve a screw and a nut and which may be of the conventional right-and-left hand thread type as used in connection with certain types of machine tools such as lathes, though the invention is illustrated in a form in which a one-hand screw is reversed as to the direction of rotation at the end of each stroke, and with the nut coupled to the piston rod, and in which the screw telescopes within the piston rod, andwith the reversing mechanism 3 controlled by members associated with the piston rod IS.

The piston rod has an axial bore H which extends almost baek to its connection with the piston 13, and this piston rod is provided with the conventional packing gland I 8 and terminates at its outer end in a thrust member E9 of increased cross-section, and an air bleeder passage 2!) permits breathing of air as the driving screw 2] passes inwardly and outwardly in the axial bore 11, and also provides a means of oiling this bore and the screw.

The crosshead guides 22 and 23 simultaneously function as tie rods, having on end fixed in the cylinder head I2 and the other end anchored in the standard 24 as indicated at 25 and 25.

The cross head 21 has bearings .28 and 29 slidable on the tie rods 2?. and 23, and consists of two cooperative members bolted together as indicated at 38, and having a bore and socket 3! formed to receive the outer end of the piston rod with its thrust collar 19, and in axial alignment has a threaded passage 32 forming the nut and extending the rest of the way through the crosshead from the socket, for cooperation with the driving screw 2!.

The thrust member or standard 24 is preferably made integral with the base 35 on which the cylinder and other operating parts are supported, and has a cap member 3Q which is bolted to the base member 24 as indicated at 35, and a bearing 36 is provided for the screw 2 l, and suitable thrust collars 3'! and 38 are provided on the screw to cooperate with the ends of the bearing or bearing thrust faces to take the thrust of the screw in either direction in driving the piston.

The reversing system may consist of any suitable arrangement which will time and reverse the movement of the piston at the proper instant near the end of each stroke, and is illustrated in its simplest form as consisting of bevel gears 39, 40 and M of which the gear 49 drives the other two gears in opposite directions, and which gear 40 may be driven through any suitable drive arrangement such as a pulley l2, gears 39 and 4i being freely rotatable on the shaft extension 43 of the screw.

Slidably and non-rotatably operative on this.

, trated at 55 and 45, and a shifter collar l? is formed intermediate the length of the hub and is adapted to rotatably and non-slidably support the shifter ring 48.

The terminal end of the shaft extension for the screw is rotatable in the bearing 49 while th drive shaft for the gear 40 is supported in the bearing 51 and driven by the pulley 42.

A shifter yoke 52 cooperates with diametric pins 53 on the shifter ring 48 and is supported on a shaft 54 which in turn is supported in a bearing 55. A shifter arm 55 is fixed on the outer end of this shaft 54 and its free end cooperates with a collar 57 located centrally of the common core of a pair of solenoids 58 and 59, though separate cores may be used with a common connection to the shifter arm.

The clutch control is through the solenoids,

and the solenoid control consists of a switch.

including a switch arm 55 and an operating lever 6| pivoted on the same shaft or pivot 62 and connected intermediate their lengths by a tension spring 63, or any combination of the. snapswitch type, with stops 64 provided for limiting the movement of the operating lever in either direction. Spaced contacts 65 and 65 are located for cooperation with the switch arm in its respective positions.

The pivot 52 or switch arm 60 is connected to one side of a power supply through a conductor 51 while one terminal of each of the two solenoids is connected to the other side of the power supply through a conductor 58, the contact 55 being connected to the other terminal of the solenoid 58 through a conductor 69 while the contact 55 is connected to the other terminal of the solenoid 59 through .the conductor 1!].

The control means for the switch consists of a control member H which is centrally secured to the crosshead 21 as indicated at E2 and has depending fingers provided with adjustable means 73 and 14 for cooperation with the lever 5i, and adjustable for exact timing of piston reversal.

Obviously, if a reversible motor should be used for driving instead of the reversing gear and clutch mechanism, a conventional reversing switch would be substituted for the snap switch and would be controlled in a similar way.

As will be noted, with the pulley i2 driving the gear 45 continuously in one direction, if the current is cut off through the power line 61-58, the gears 59 and 4! will simply run idle with neither clutch in engagement.

When the current is turned on, with the snap switch in the position shown, solenoid 59 will become energized and move the clutch as into engagement with the gear 39, driving the screw 2! in one direction. The screw operates in the threaded passage 32 drawing the crosshead to the right, and with it, through the thrust member 19, the piston rod I6 and piston I3, the screw entering deeper into the axial passage il in the piston rod but having no threaded cooperation with the walls of the bore in the piston rod. Trapped air or oil will pass about between the threads and any excess will escape through the passage 20, and air will be drawn in the same way when the screw is retracted from the passage ll.

, In the position illustrated the screw is already moving the switch lever 6|, and as the crosshead moves to the right it will gradually move the operating lever until it passes the common center l5 when the spring 63 will snap the switch arm 55 from contact 65 to contact 56, breaking the circuit to solenoid 59 and completing circuit to solenoid 58 which instantly moves the clutch 45 out of driving engagement followed by immediate moving of the clutch 46 into engagement, reversing the direction of rotation of the screw to drive the piston in the opposite direction or to the left as viewed in the figures, until the screw M on the control member ll again moves the operating lever past the opposite common center. The screws 73 and 14 permit adjustment of the time of reversal at any exact point in the stroke desired, for which reason it is possible to adjust the length of the stroke for any desired displacement or volume of delivery per stroke, and which is another of the many advantages of this invention. Thus it is possible to adjust the rapidity of the surges from slow and relatively long, to rapid and relatively short, as the particular process may require for highest efiiciency, and without any change other than the adjustment of the screws 13 and M.

The pump is adaptable to many purposes, but is mainly designed for surging a liquid while also delivering a measured amount of fresh liquid to a receptacle or column.

To accomplish this a special valve arrangement is required. The intake valve is illustrated in Fig. 3 and one of these is located at each end of the cylinder l9, and each includes a valve chamber 16 in communication with the intake port I4, and an intake line 11 with a passage from the intake line to the port controlled by a valve 18 having a valve stem 19 which is slidable in an axial bore 80 formed in the adjusting screw 8| which is secured in position by a locknut' 82, and which valve is urged to close by a compression spring 83. The cap 84 permits replacement or repair of valves at will and supports the screw 8|. The lift of the valve is limited by the space between the top of the valve stem and the bottom of the axial bore, therefore the farther the screw BI is adjusted down the more restricted will be the valve opening for limiting the volume of fresh fluid taken in to the cylinder with each stroke.

The discharge valve is illustrated in Fig. 4 and operates oppositely from the intake valve in that the degree of closing is limited, and in its simplest form includes a discharge chamber 85 in communication with the discharge port l5, with a valve 86 controlling flow of fluid from the discharge port to the discharge line 81, or in the opposite direction.

The valve 86 has a valve stem 88 which is slidable in an axial bore 89 formed in the adjusting screw 90 and has a spring 9| to urge the valve to seat. The entire discharge valve systern is similar to that of the intake valve system with the exception that a diametric slot 92 is formed in the adjusting screw, and a pin 93 is fixed in the valve stem and operates in the slot 92 to limit the movement of the valve toward its seat so that a measured quantity of fluid will be retracted with each stroke. The farther up the screw is adjusted, the greater will be the minimum opening of the valve, and if adjusted down sufficiently, the valve will operate in a normal manner under sole control of the valve spring, while the intake valve will be free to operate normally under the sole control of its valve spring if the adjusting screw is adjusted up far enough.

With this system, if screw BI is adjusted up far enough, and screw 90 down far enough, the unit will operate as a conventional reciprocating pump, taking in a fresh charge of liquid at one end of the cylinder while simultaneously discharging at the other end of the cylinder The following operations and combinations are possible:

1. Adjusting all valve screws for free operation provides a conventional reciprocating pump.

2. Adjusting the intake screws to prevent opening of the intake valves, and. the discharge valve screws to prevent closing of the discharge valves, provides a straight surge or breather pump.

3. Adjusting the intake valve screws to permit only partial lift, and the discharge valve screws for only partial closing of the valves provides a combined circuit and surge pump, each stroke taking in a portion of its volume of fresh liquid through the intake valve while retracting the rest of its volume from the previous discharge through the discharge port.

4. Adjusting one end according to (1) and the other end according to (2) provides a conventional pump at one end and a surge or breather pump at the other end.

5. Any combination of the above, and including pumping and/or surging from different sources or to different destinations.

6. Adjusting the switch control screws for any desired displacement or length of stroke, or for any speed of reciprocation within the limits of adjustability.

By taking in a small supply of fresh cold liquid at each stroke when surging, the oil in the cracking column is replenished, and the pump operates on relatively cold fluid.

It will be understood that variations in construction and arrangement of parts, and elements used, which variations are consistent with the appended claim, may be resorted to without detracting from the spirit or scope of the invention, or sacrificing any of the advantages thereof.

I claim:

Driving means for a pump having a cylinder and a piston rod, comprising a standard having a bearing supported thereon, and tie rods anchoring said standard to said cylinder and simultaneously functioning as crosshead guides; a crosshead slidably operative on said guides and intermediately coupled to the end of said piston rod and having a nut included therein and forming a coupling for said nut to the outer end of the piston rod; a screw journaled in said hearing and threadedly operating in said nut and an axial bore formed in said piston rod to receive the screw as it operates through said nut.

JOHN C. WILLIAMS.

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

UNITED STATES PATENTS Number Name Date 38,736 Fitzpatrick June 2, .1863 268,631 Dampman Dec. 5, 1882 411,263 Sherman Sept. 13, 1889 499,934 Pine June 20, 1893 863,966 Billeter Aug. 20, 1907 1,416,182 Former May 16, 1922 1,942,189 Shepard Jan. 2, 1934 2,011,831 Sinanide Aug. 20, 1935 2,307,317 Konig Jan. 5, 1943

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