US2159720A - Pump - Google Patents

Description

May 23, 1939- l l G. A. WAHLM'ARK v v 2,159,720

` j PUMP y Filed Feb. 27, v19:56 s sheets-sheet 2 May 23, 1939.l

G. A. WAHLMARK PUMP Filed Feb. 27, 1936 l l A g Hill il 3 Sheets-Sheet 3 Patented May 23, 1939 UNITED STATES*V PATENT -oFFlcE PUMP Gunnar A. Wahlmark, Rockford, lll.

Application February 27, 1936, Serial No. 66,009 A 12 calms. (ci. 10a-12s) i The invention relates to pumps and `has as a general object to provide a rotary pump. of -novel and improved construction which is quiet and eflicent in operation, compact and rugged in construction, andl readily installed and adjusted.

A primary object of the invention is to provide a single stage rotary pump of novel and improved construction capable of running quietly and eiilci'entlywhile operating at high vacuum and against high pressure.

Another object is to provide a pump having a single stage composed of rotary pumping elements', an intake port and a discharge port for vthe stage, an auxiliary reservoir receiving a portion of the liquid pumped, and an auxiliary inlet port disposed intermediate the regular ports and supplied with liquid from.the auxiliary reservoir t'ofill completely the recess in the pumping ele- I mentsl and thus enable the pump to operate quietly when operating at high vacuum and against high pressure.

Yet another object is to provide` a pump having a pressure actuated discharge control means and a bleed passage adjustable to vary the length of time after starting of the pump when the control'means will permit discharge from the pump.

A further object is to provide in a pump a valve controlling the discharge from the pump, a pis-V ton for actuating the valve responsive to the pressure of the liquid discharged and having an annular undercut in its outer surface, and a byn pass passage discharging through the undercut on the piston to a reservoir in the pump to maintain the piston lubricated and thereby assure ready response to the piston to changes in pressure. Other objects and advantages will become apparent from the following detailed description taken in connection with the accompanying drawings, in which:

.Fig 1 is a vertical diametrical section of a pump embodying the features of the invention. Fig.'2 is a partial transverse sectional view taken along line 2--2 of Fig. 1.

Fig. 3` is a partial transverse sectional view taken along line 3-3 of Fig. 1.

Fig. 4 is a partialtransverse sectional View taken along line 4 4 of Fig. 1.

Fig. 5 is a partial transverse sectional view `taken along line 5-5 of Fig. l. o

i Fig. 6 is a fragmentary view showing the disfrfcharge control valve and Apiston in closed position.

Fig. 7 is a view like Fig. 6 showing the disand scope of the invention as defined by the appended claims.

As shown in the drawings for purposes of disclosure, the pump is of the rotary type having an elongated casing comprising a horizontally disposed cup-shaped member l0, forming one end of the casing. within which is disposed a pump chamber proper and pressure actuated means controlling the discharge from the pump. Secured over the open end of the cup-shaped member I0 as by bolts II is an end closure I2 completing the casing and having an axial extension I2. A gasket I3 is interposed between the 25 cup-shaped member I0 and the end closure I2 to make the joint duid-tight so that the casing in addition to housing the pumping and control means constitutes an auxiliary reservoir Il. Depending from ther cup-shaped member I0 and removably secured thereto in fluid-tight relation is a strainer cup l5 within which is supported a double screen strainer I6,

As stated above, there is disposed within the casing a pump chamber proper. One end wall of the chamber is formed by the end closure I2, while the other end wall is formed by a plate I8 spaced from the end closure by an annular ring I9 constituting the periphery of the pump chamber. Housed Within the pump chamber and operable to draw fluid into the chamber and forcibly discharge it therefrom are rotary pump elements of the general character disclosed and claimed in my copending applications Serial No. 675,218, filed June 10, 1933, and Serial No'. 14,017, filed April 1, 1935, comprising an internally toothed rotor 20 rotatable within the annular ring I9. Positioned eccentrically within the rotor 20 and meshing therewith over a portion of the circumference only is a roller 2I and interposed in the space .left by the eccentricy mounting of the rotor and roller is a crescent-shaped element 22 completing the pump chamber. The axialdimensions of the rotor and roller are such that the end faces have a sliding but fluid-tight engagement with the end wallsof the chamber.

Here the roller 2I is the driving element and to that end is secured as by a key 25 to a shaft 26 journaled in the axial extension I2C/and projecting outwardly thereof. To prevent leakage along the shaft, a. collar 21 is secured to the shaft by a driving ring 28 and bears/against an annular sealing member 29 of a. rotary mechanical seal. The member 29 is secured to and suspended by a waterproof fabric diaphragm'29' disposed with its outer periphery in a recess 30 formed in an elongated housing 3I threaded into the end closure I2. The diaphragm is secured in the recess by being clamped between shoulder 3|' and an apertured cap 29" forced into the recess by a nut 32 threaded into the recess. The cap 29" is preferably formed of resilient metallic material and with a somewhat convex shape adjacent the shaft so that the nut 32 engages the cap near its inner edge. Thus the cap compensates for any misalinement between the nut 32 and the shoulder 3| and serves automatically to take up any looseness caused by compression of the diaphragm against the shoulder. A spring 32 urges the member 29 into contact with the collar 2 1. Preferably a gasket 33 is interposed between the housing 3| and the end closure I2. Upon rotation, the pump elements operate in well known manner to draw liquid into the pump chamber and forcibly discharge the same therefrom. To provide an intake passage for the pump chamber, the end closure I2 is formed with a radial bore 35 which is threaded at 36 for the reception of a conduit (not shown) leading to a supply reservoir. Extending laterally from the bore 35 is a passage 31 registering with a passage 38 in the cup-shaped member I6, discharging to the strainer bowl I to one side of the strainer. Leading from the opposite side of the strainer is a duct 39 registering with a duct 4U, in the end closure, communicating with the bore 35 radially inwardly of a ball 4I forced into the bore 35 to seal the passage 31 from the duct 40. The extreme inner end of the bore 35 communicates with a duct 42 (see Fig. 5) leading to an intake port 43 for the pump chamber completing the intake passage. Discharge from the pump chamber is through an exhaust port 45 and a duct 46 in the plate I8 (see Fig. 2) and thence through a duct 41 formed in part in the plate I8, the annular ring I9 and the end closure I2 where it communicates with a threaded outlet 48. f The outer end of the portion of 'the duct 41 in the plate I8 is closed by a ball 41' wedged into the duct.

Means is provided herein for controlling the lapse of time between starting of the pump and discharge of liquid from the casing and for effecting sharp cut-off in order to adapt the pump particularly for use with oil burners. To that end there extends axially from the plate I8 a cylinder 56 into which the duct 46 discharges. The cylinder is provided with a radial flange 51 and is secured in position by bolts 58 extending through the flange, the plate I8, and the annular ring I9 and threaded into the end closure I2 so as to secure all as a unit to the end closure. Slidable in the cylinder 56 is a piston 66 so as to form with the plate I8 and the cylinder 56 a variable chamber 6I and to have its end exposed to the liquid discharged from the pump chamber through exhaust port 4'5 and duct 46. Carried in a bore 68 in the piston and having a limited longitudinal movement relative thereto is a valve 62 having a tapered end for engagement with a valve seat 63 at the outer edge of a bushing 64 fixed in the plate I8 and communicating with the discharge duct 41. The piston is held against rotation by a pin 56 projecting from the plate I8 into a recess in the piston formed for that purpose. v

Discharge from the pump casing takes place when the pressure in the chamber 6I is sufficient to move the piston 60 and the valve 62 in a direction away from the plate I8 against the opposition of a compression spring 65 bearing at one end against the piston 60 and at the other end against a plate 68. The discharge pressure may be varied by adjusting the plate 66 longitudinally, which for Vthat purpose is threaded onto the end of an elongated adjusting sleeve 61 extending through an aperture 68 in the closed end of the cup-shaped member I6 and held against outward movement by a bevelled ange 61 thereon. The plate 66 is held against rotation by a bolt 69 which slidably engages in a notch 66 in the plate so that the discharge pressure may be readily varied by rotation of the sleeve 61 by the use of a suitable tool engaged in an end slot 61". Concealing the outwardly projecting end of the sleeve is a cap 18.

For a purpose which will become apparent shortly, the valve 62 has, as stated above, a slight longitudinal movement relative to the piston 60. To limit such relative movement in a, direction toward the plate I8, the valve is formed with an annular flange 13 adapted to engage a shoulder 14 in the bore 68 of the piston 86. To limit movement of the valve relative to the piston in the opposite direction, an adjustable stop 15 is threaded into the bore of the piston to be abutted by a reduced end 16 of the valve 62. Interposed between the adjustable stop and the flange on the valve is a compression spring 18 urging the valve into engagement with the shoulder 14 of the piston. The stop 15 may be adjusted from the exterior of the casing by removal of the cap and a plug 19 threaded into a bore 80 formed in the sleeve 61 for the purpose of giving access to the stop by a suitable tool.

For the purpose of supplying liquid to the auxiliary reservoir I4 and for the purpose of delaying actuation of the valve 62 after starting of the pump, an adjustable but constantly open bleed passage is provided. To that end the valve 62 has a notch 85 increasing in depth as it approaches the tapered end of the valve and the piston 68 is formed near the corresponding end with an annular groove 86 forming with the notch a variable bleed opening communicating with the chamber 6I. The groove 86 communicates by means of a radial downwardly directed duct 81 with an annular undercut 88 in the outer surface of the piston. A portion of the pump output discharged to the chamber 8| thus flows through the opening formed by the notch 85 into the annular passage 86, thence through the duct 81, the undercut 88 and out through an opening 89 in the top of cylinder 56 to the reservoir I4.

The size of the opening formed by the notch 85 may be varied by adjusting the stop 15 which determines the position of the valve relative to the piston 56 when the pump is idle, and thus permits a greater or lesser bleed of liquid from the chamber''l. When the opening is large the the discharge passage controlled by valve 82 built upvshortlyafter starting ofthe pump. Upon shiftingAv of the piston by the building up of pressure, a: relative movement of `the piston and valve, limited by-abutment of theflange 13 with shoulder 14, takes place and as aresult the bleed opening is closed slightly over its size when the pump is idle, but the opening is never completely closed so that therel is a constant bleed around the piston and into' the auxiliary reservoir I4. There is also a second `bleed or by-pass passage from chamber 6I to undercut 88 `(F'igf) formed by `a recess 89 in cylinder 56, which is uncov- `cred when piston 60 is shifted to open valve 62.`

There is thus a constant flushing of the undercut 88 making the piston readily responsive to the pressure in the chamber 6I and maintaining the reservoir I4 lled with liquid. Thegreater p0rtion of the liquid discharged to lthe reservoir flows through undercut 89'.

Means is also provided herein for enabling the pump to operaio quietly and efficiently at high vacuum and againsthigh pressure. To that .end :an-auxiliary intake port 92 is provided (see Fig. 2) located intermediate the intake port 43 and the discharge port 45 to supply liquid to the recesses in the pumping elements while they'are in engagement with the-crescent shaped member 22. The port 92 is supplied with liquid from the auxiliary reservoir I4 and communicates therewith near the bottom' thereof through a passage 93 formed `in the plate I8. The plate I8 is slightly smaller in diameter than the internal diameter of the cup-shaped member I 0 in the plane of the plate so as to provide aspace 94 by means of which the duct 93 opens tothe reservoir. In this manner the recesses in the `pumping elements, which are only partially lled when the pump is operating at high vacuum, are completely lled by the liquid in the reservoir I4 and thus notonly is the ef' iiciency of the pump increased but the noiseat the exhaust port resulting from the operation ofthe pump with only partially iilled recesses is eliminated. Any excess of liquid fed into the `reservoir I4 over the quantity drawn from the reservoir through the auxiliary port92 is returned to the main reservoir through an opening 95 in the top of the member Ill which is above the level of the port 92.1 If'there is a `gravity feed to the pump the plug 96 in the bottom of the member I9 may be removed and the opening 95 closed and the return pipe dispensed with.

The operation of the pump is best understood from a consideration of Figs. 6, 7 and 8 which show the control means in the various positions assumed during the operation of the pump. When the pump is idle the control means is in the position shown in Fig. 6. Valve 62 then is seated to close the discharge passage 41 and piston 68 has been urged toward the plate I8 by the spring 65 to an extent permitted by abutment of the stop 15 with the end 16 of the valve. This position of thel valve and the piston determines the original size of the bleed opening formed by notch 85 and groove 86 and this opening may be increased or decreased by rotation of the stop 15 whereby the relative position of the piston is changed with respect to the Valve.

Upon starting of the pump, liquid is drawn through the intake passage and the intake port 43 and discharged through the. exhaust port 45 and duct 46 into the chamber 6I. `The initial discharge from the pump flows through the bleed passage formed by notch 85, groove 86, duct 81,

undercut 88 and opening 89 to the auxiliary reservoir I4. Not until some time after commencement of operation of thepump is a sufficient size and the continued discharge of liquid im-y mediately forces the piston still farther away from theplate I8 and the shoulder 14 thereon engages the ange 18 on the valveandlmoves the same away from its seat to permit discharge from the pump. The piston and valve are now in the position shown in Fig. 8 which is the position they retain during operation of the pump.'

In shifting to the position shown in Fig. 8, piston 60 has uncovered the recess 89 in cylinder 56, n

thereby opening another passage leading from chamber 6| to reservoir I4 by way of the under-v cut 88 in piston 68. The delay between the starting of the pump and the discharge of liquid from the casing may be varied by varying the size of the bleed opening and such variation in the delay is effected simply by rotation of the stop 15. Similarly the pressure at which the valve opens` to permit discharge may be varied bythe rotation of the sleeve 61.

Should the pump be operating at such high vacuum that the recesses in the pumping elements are not completely filled, the auxiliary inlet port 92 comes into operation to supply an additional quantity of liquid completely iilling the recesses. This liquid isdrawn from the auxiliary reservoir I4 which is constantly supplied through the bleed and by-pass passages.

single stage operates as efliciently and quietly at high vacuum and against high pressure as a double pump.

When the pump is stopped the piston and the valve immediately move toward the plate I8 maintaining the liquid in the chamber 6I under full pressure until the valve is seated so that a sharp cut-01T and a iinal discharge under full pressure are obtained. The parts of the control means now are again in the position shown in Fig. 6.

I claim as my invention:

1. A rotary pump comprising, in combination; a casing providing an auxiliary reservoir, means within the casing forming a pump chamber, ro-

tary pumping elements housed in the chamber comprising a rotor and a roller disposed eccentrically within the rotor and meshing therewith over a portion of its circumference only, a cres-` cent-shaped member interposed between said elements in the space formed by the eccentric mounting thereof, an intake passage for the pump chamber including an intake port disposed on one side of the point of engagement of said pumping elements, a discharge passage including a discharge port disposed on the opposite side of the point of engagement of said elements, a drive shaft for rotating said elements, said elements being operable upon rotation to draw liquid into the pump chamber and forcibly discharge the same therefrom, a passage for conducting a portion of the liquid discharged from the chamber to the auxiliary reservoir in the casing, and an auxiliary intake port for the pump cham-` ber disposed intermediate the intake and exhaust ports and supplied with liquid from the auxiliary By lling the recesses in this manner the pump with but a.

reservoir to compensate for any deilciency at the intake port when the elements are operating at high vacuum and against high pressure.v

2. A rotary pump comprising, in combination, a casing providing an auxiliary reservoir, an overflow opening for the reservoir in the casing, means within the casing forming a pump chamber, rotary pumping elements housed in the chamber comprising a rotor and a roller disposed eccentrlcally within the rotor and meshing therewith over a portion of its circumference only, a crescent-shaped member interposed between said elements in the space formed by the eccentric mounting thereof, an intake passage forthe pump chamber including an intake port disposed on one side of the point of engagement of said pumping elements, a discharge passage including a discharge port disposed on the opposite side of the point of engagement of said elements, a drive shaft for rotating said elements, said elei ments being operable upon rotation to draw liquid into the pump chamber and forcibly discharge the same therefrom, a passage for conducting a portion of the liquid discharged from the chamber to the auxiliary reservoir in the casing, an auxiliary intake port for the pump chamber disposed substantially diametrically opposite the point of engagement of said elements, and a duct communicating at one end with said auxiliary port and at the other end communicating with the auxiliary reservoir near the bottom thereof, said auxiliary port being disposed below the overow opening in said casing.

3. A pump comprising, in combination, means forming a pump chamber having an intake port and a discharge port, pumping elements housed in the chamber operable to draw fluid thereinto and forcibly discharge fluid therefrom and into a valve chamber, valve means responsive to the pressure of the fluid in the Valve chamber controlling discharge from the valve chamber, an open internal bleed passage from said valve chamber, and adjustable means carried on said valve means and accessible fromv outside the valve chamber for varying the size of the bleed passage to vary the delay in the discharge from the pump after initiation of operation of the pump.

4. A pump comprising, in combination, means forming a pump chamber, means including a piston subject to a pressure differential forming a variable chamber, an intake passage for the pump chamber, a discharge passage communicating at one end with the pump chamber and at the other end with the variable chamber, pumping elementsin the pump chamber operable to draw fluid into the pump chamber and forcibly discharge the same therefrom, a valve carried by said piston controlling the discharge from said variable chamber, said valve being yieldably retained seated until a predetermined pressure is attained in the variable chamber, a bleed passage leading from said variable chamber directly to the low pressure side of the piston to delay discharge from the chamber after initiation of operation of the pump, and means carried on said piston for adjusting the bleed passage.

5. A pump comprising, in combination, means forming a pump chamber, means including a pressure actuated piston forming a variable chamber, an intake passage for the'pump chamber, a discharge passage leading from the pump chamber to the variablechamber, pumping elements in the pump chamber operable to draw fluid into the chamber and forcibly discharge the same therefrom, a Valve carried by said piston control- `ling the discharge from said variable chamber.

means maintaining said valve seated to prevent discharge until a predetermined pressure is attained in the variable chamber, a bleed passage communicating with the variable chamber through an opening formed intermediate the valve and the piston to delay actuation of the piston, and adjustable means varying the relative position of said valve and piston to vary the size of the bleed opening.

6. A pump comprising, in combination, means forming a pump chamber, means including a pressure actuated piston forming a variable chamber, an intake passage for the pump chamber, a discharge passage communicating at one end with the pump chamber and at the other end with the variable chamber, pumping elements in the pump chamber operable to draw iluld into the chamber and forcibly discharge the same therefrom, a valve carried by said piston controlling the discharge from said variable chamber. said valve being movable relative to said piston, a bleed passage communicating with said variable chamber comprising an annular groove in the piston and a notch of varying depth formed in said valve r opposite the groove, and means for adjusting the position of said valve relative to said piston to vary the size of the bleed opening formed by the notch in the valve and the piston.

'7. In a pump having pumping elements, discharge control means comprising means including an axially movable piston forming a variable chamber receiving the fluid discharged by the pump elements, said piston being movable to vary the capacity of the chamber, a valve carried by said piston 'controlling the discharge from the variable chamber and operable upon the creation of a predetermined pressure in the chamber to permit discharge therefrom, a, bleed passage communicating with the variable chamber and controlled by said valve and including an annularundercut in the periphery of said piston, and means for adjusting the valve relatively to the plston to vary the bleed passage` 8. In a pump having pumping elements, discharge` control means comprising means including an axially movable piston forming a variable chamber receiving the fluid discharged by the pumping elements, a valve carried by said piston and movable axially relative thereto controlling the discharge from the variable chamber and operable upon the creation of a predetermined pressure in the chamber to permit discharge therefrom, and a bleed passage communicating with the variable chamber comprising a. notch in the valve, a groove in the piston opposite the notch and forming therewith a variable bleed opening, a radial duct leading fromthe groove, and an annular undercut in the periphery of the piston to which the radial duct discharges.

9. In a pump having pumping elements, discharge control means comprising means including a horizontally disposed cylinder and an axially movable piston therein forming a variable chamber receiving the fluid discharged by the pumping elements, a discharge passage leading from the variable chamber, an axial bore in said piston providing a shoulder, a valve for controlling the discharge passage disposed in the bore in said piston having an annular flange adapted to engage the shoulder in the bore to limit movement of the valve relative to the piston in one direction, a stop threaded into the bore of the piston to limit movement of the valve in the opposite direction, a compression spring interposed into engagement with the shoulder in the bore,

said stop being adjustable to vary the relative position ofthe valve and piston, a bleed passage communicating with the variable chamber comprising a notch of varying depth in the valve, a groove opening into the bore of the piston opposite the notch to form therewith a bleed opening variable by adjustment of the stop, a downwardly directed duct leading from the groove in the piston, an annular undercut in the periphery ofthe piston to which the duct discharges and an aperture in the top of the cylinder communicating with said undercut, and a compression spring urging said piston in a vdirection to reduce the size of the variable chamber and to seat the valve.

10. A pump comprising, in combination, a casing providing an auxiliary reservoir, meanswithin the casing forming a pump chamber, means includingan axially movable piston forming a variable chamber, an intake passage for the pump chamber including an intake port, a discharge passage leading from the pump chamber to the variable chamber, a discharge port from the variable chamber, rotary pumping elements disposed in the pump chamber operable upon rotation to draw liquid through the intake passage and discharge the same forcibly through the discharge passage, a bleed passage communicating with the variable chamber and discharging to the auxiliary reservoir, said bleed passage being constantly open, a valve device adjustably mounted on said piston and operable to control the discharge of liquid from the variable chamber both through 'the discharge port and the bleed passage, and an auxiliary intake port for the pump chamber supplied with liquid from the auxiliary reservoir.

11. A rotary pump comprising, in combination, a casing providing an auxiliary reservoir, means within the casing forming a pump chamber proper, means including an axially movable piston forming a variable chamber, rotary pumping elements disposed in the pump chamber comprising a rotor and a roller mounted eccentrically therein and meshing therewith over a portion of its circumference only, a crescent/-shaped member interposed between the rotor /and roller in the space formed by the eccentric mounting thereof, an intake passage for the pump chamber including an intake port, a discharge port communicating with the variable chamber, said pumping elements being operable upon rotation to draw liquid into the pump chamber and forcibly discharge the same into the variable chamber, a discharge passage leading from the variable chamber, a valve carried by said piston controlling the discharge passage, a compression spring urging said piston in a direction to close the valve, a permanently open bleed connection leading from said variable chamber to the auxiliary reservoir, and an auxiliary intake port disposed intermediate the intake and discharge ports of the pump chamber supplied with liquid from the auxiliary reservoir.

12. A pump comprising, in combination, means forming a pump chamber, means including a cylinder and a piston movable axially in the cylinder forming a variable chamber, an intake passage for the pump chamber, a discharge passage leading from the pump chamber to the variable chamber, pumping means within the pump chamber operable upon actuation to draw liquid into the pump chamber and forcibly discharge the same therefrom, a valve carried by said piston controlling the discharge from the variable chamber, said piston being shiftable upon the creation of a predetermined pressure in the.' variable chamber to move the valve to permit discharge from the variable chamber, and a bypass passage including an annular undercut in the periphery of said piston and an undercut in said cylinder communicating with the undercut in the piston and uncovered upon shifting of .the piston to valve-open position to effect communication of the undercut with the variable chamber.

GUNNAR A.

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