US 3044484 A
Description (OCR text may contain errors)
July 17, 1962 1.. DUNNING 3,
BY-PASS VALVES Filed June 8, 1959 3 Sheets-Sheet l 7'0 IVOZZZE FROM T4/V/\ A TTORNEYS.
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L. DUNNING BY-PASS VALVES July 17, 1962 Filed June's, 1959 5 Sheets-Sheet 3 Z w m QM W m J W a3 a L m 3 N as h sum QR Q QQ gm MN gm. UN NMNRN fin I Q wwm m MQNRN Unite States 3,044,484 BY-PASS VALVES Leighton Dunning, Philadelphia, Pa., assignor to William M. Wilsons Sons,'Inc., Lansdale, Pa., a corporation of Pennsyivania Filed June 8, 1959, Ser. No. 818,726 2 Claims. (Cl. 137-469) This invention relates to by-pass valves. More specifically, it has to do with by-pass valves useful, for example, in connection with apparatus for dispensing liquid commodities such as gasoline, fuel oils and/or other petroleum products at motor vehicle filling stations. In apparatus of the kind referred to, the liquid is drawn by a motor-driven rotary or other positive displacement pump through a pipe from an underground storage reservoir and, after passing through a meter, is discharged into a delivery hose having a manually operable nozzle at its distal end.
The chief aim of my invention is to provide a bypass valve for the purposereferred to which is simple in construction and relatively inexpensive, and which is automatically operative, upon partially or completely shutting off the hose nozzle, to allow free circulation of the liquid from its outlet port to its inlet port, and which is so constructed as to cause the pump pressure to decrease with attendant greater opening of the by-pass valve, and thereby minimize wear of the pump and the power required to drive it.
Other objects and attendant advantages will appear from the following detailed description of the attached drawings, wherein:
FIG. 1 is a view, partly in elevation and partly in section, of the pump and metering unit of a liquid dispensing apparatus with an incorporated by-pass valve conveniently embodying my invention.
FIG. 2 is a view, likewise partly in elevation and partly in section, the section being taken as indicated by the angled arrows 11-11 in FIG. 1.
FIG. 3 is a fragmentary sectional view on a larger scale corresponding to FIG. 2 and showing the valve in closed position.
FIG. 4 is an enlarged view similar to FIG. 3 showing the valve open for by-passing of liquid through it.
FIGS. 5 and 6 are views similar to FIGS. 3 and 4 showing an alternative embodiment of the invention; and
FIG. 7 is a perspective view of one of the component parts of the alternative embodiment.
With more detailed reference to FIGS. 1-4; the pump and metering unit therein illustrated is, generally speaking, of well known construction in that it comprises a rotary pump :1 (FIG. 2) driven by an electric motor 2, and a meter 3 to which is connected, through an elbow 4 (FIG. 1), a hose 5 through which the liquid is dispensed.-
It is to be understood that, as usual, the hose 5 is provided at its distal end with a manually-operable control nozzle (not illustrated) which may be of any well known commercially-available type. The bypass valve of my invention, comprehensively designated 6 in the drawings, is enclosed, together with the pump 1, the motor 2 and the meter 3, in a protective housing 7 which is supported by a fitting 8 at the top of the stand pipe 9 rising from a supply reservoir (not shown) for the liquid, said casing being provided with a removable cover 10 so that access may be had to its interior when desired or necessary for any reason. 7
As herein illustrated, the body 11 of my improved bypass valve 6 has an open top chamber 12 with a flow outlet 13 at one side in direct communication with the inlet port 14 of the pump 1, and a crosswise flow passage 15 beneath said chamber set apart from the latter by a horizontal partition 16, said passage communicating at one end, as at 17, with the outlet port 18 of the pump, and at the other end, by Way of an elbow connection 19 and a short pipe 20, into the bottom of the meter 3. From FIG. 1 it will be noted that the body 11 of valve 6 has a hollow lateral extension 21 which, through a vertical tube 22, is in communication with the fitting 8 at the top of the stand pipe 9. The lateral extension 21 of the valve body 11 is in communication, by way of a port 23 and the hollow of a bolted-on cover 24, with the top of the chamber 12. Arranged to cooperate with the seat of the "port 23 at the top of the extension 21 is a check valve of which the closure element 25 is yieldingly urged downward by a spring 26, maintained in compression by reason of being positioned in abutment with the under surface of cover 24 Disposed within the chamber 12 of the valve body 11 is a removable insert comprising a hollow cylinder 3%) which, at its lower end, is engaged in an annular shouldered recess 31 surrounding a port 32 in the partition 16, said port being smaller in diameter than the recess and merging with said recess through a bevel 32a. At the top, the cylinder 30 is closed by a head 33 and is held in place by engagement of spaced lugs 24a formed integrally on the cover 24 with said head. Arranged to cooperate with a seat gasket 35 lodged in the recess 31 is a disk 36 which has a loose fit in the cylinder and is afiixed to a rod 37 constrained to end-wise movement axially of the cylinder 30 in a guide aperture in the head 33. The rod 37 is prolonged below the disk 36 and to the bottom end thereof is secured a smaller disk or piston 49 which (see FIG. 3) has a free fit within the smaller lower portion of the port 32 in partition 16. By means of a long soft or light helical spring 41 within the cylinder 30 in compression between the head 33 and the disk 3d, said disk is yieldingly normally maintained in engagement with the seat gasket 35. As further shown, the cylinder 39 has a series of circumferentially-arranged lateral apertures 42 above the wall of partition 16 and is surrounded by a tubular screen 43 of larger diameter. The screen 43 is open at the top and fits snugly into the top opening of the chamber 12, said screen extending down to a level short of the lateral apertures 42 in the cylinder 36 and being closed at the bottom as at 43a by a similar screen, or alternatively by an imperforate closure.
In the embodiment of FIGS. 5-7, the port 32b in the partition 16b is made plain cylindric, and the disk 36b is made to close directly upon the seat 31b. Here however, the smaller piston element 40b has the form of a plunger of which the upper portion is cylindrical and circumferentially grooved and the lower portion is tapered as shown, the cylindrical portion having a free piston fit within the port 32b. A further modification to be noted in this embodiment is that the cylinder 30b is formed with a plurality of circumferentially spaced circular apertures 42b and a corresponding number of alternately intervening vertically elongated apertures 42b. These apertures 42b may be keyhole shaped as shown, or they may be made as downwardly tapering triangles, or other shapes may be utilized as long as the area of the aperture increases from the lower to the upper portion thereof. In order to obviate the necessity for repetitive description, all the elements of the modified valve not particularly referred to but having their counterparts in the first de scribed embodiment, are identified by the same reference characters previously employed but with addition, in each instance, of the letter b for convenience of more ready distinction.
Operation With the pump 1 in action and the nozzle at the end of the hose 5 open, liquid is drawn up through the stand pipe 9 and the tube 22. into the offset 21 of the body of the valve 6 past the closure 3 element 25 of the check valve (which will rise in response to pump suction), enters the top of the chamber 12 by way of the hollow in the cover 24, traverses the screen 43, entersthe pump 1 by way of the passages 13 and 14, and is discharged from the pump under normal pressure by way of the passages 18, 1'7 and 15, elbow 19 and pipe 20 into the meter 3, and from thence flows through the elbow 4 to the hose as shown by the arrows in FIGS. l-3, the disk 36 (FIG. 3) being held in closed position at this time against the seat gasket 35 by the light spring 41, the force of which is sufficient to prevent the piston 40 from rising up to the beginning of the bevel 32a when the nozzle is fully open and the pump is delivering liquid at its maximum rate as in filling an automobile tank. As the tank becomes full the discharge can be reduced to any desired rate by partially closing the nozzle. This momentarily results in increasing the pressure under the piston 40 causing it to rise and occupy a position somewhat above the start of the bevel 32a-thus providing a clearance between the piston 48 and bevel 32a. Liquid pressure will now be communicated through this clearance to the lower surface of the disk 36 and through the portion of the apertures 42 lying under and uncovered by disk 36 which results in a bypassed flow through apertures 42 and into the suction side 14 of the pump. Thus the total discharge of the constant displacement pump becomes dividedpart through the nozzle and part through the by-pass valve.
When the nozzle is sufiiciently closed to cause some by-passing, the pump pressure decreases because the force exerted by the supple spring 41 is then balanced by two forcesthe pump pressure acting against piston 40 and in addition by the auxiliary force of the liquid pressure acting against the under surface of disk 36. When the piston 40 is at any point above the beginning of the bevel 32a, the pressure of the spring 41 is balanced by the product of the pump pressure in the passage times the area of the piston 40 plus the product of the liquid pres sure in that portion of cylinder below disk 36 (acting to lift disk 36) times the difference between its area and the smaller area of piston 40.
The more the nozzle is closed, the farther up will the piston move with respect to the bevel 32a and the less will become the pressure drop as the liquid flows through the increased opening between the piston 40 and the wall 32aconsequently the greater will be the percentage of the pump pressure to act against the disk 36 and thus a lesser force (pump pressure) Will be required to act on piston 40 in order to balance the spring force.
With the noule completely closed a large proportion of the pump pressure will be exerted against the underside of disk 36. In the drawings this is particularly evident in FIG. 6 which shows passage 3% virtually free from restriction by plunger 45b.
The alternative form of the by-pass valve functions in the same way as the first described form. Upon increase of liquid pressure in the passage 1715 as the hose nozzle is either partially or fully closed, liquid flows through the port 32b gradually increases increases upon rise of the tapered portion of the piston plunger 4% from within the port 32b, and eventually acts upon the disk 36 of larger area until the valve reaches the full open position in til Al. Which it is shown in FIG. 6. It is to be particularly noted that, due to the slotted formation of the apertures 42]) in the cylinder 3011, the flow of the liquid through; I the port 32b is permitted to increase progressively as the closure element of the valve rises. As a consequence, it will be seen that opening and closing of the valve will take place with absence of any hunting or vibration.
It is to be understood that in either embodiment of the invention, the screen element may be omitted if desired or considered to be unnecessary.
While I have illustrated and described the best forms of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may he made in the forms of the apparatus described without departing from the spirit and scope of the invention as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of the other features.
Having thus described my invention, I claim:
1. A by-pass valve comprising: a casing having an upper end with a fluid inlet passage therethrough, a first outlet passage disposed below said upper end communieating with said inlet passage and a second outlet passage, said first and second outlet passages being separated by a partition, said partition having a port therein with a portion of large area and a portion of small area; an inverted cup1ike element stationarily disposed within the casing having a closed upper end spaced from said inlet passage and an open lower end bearing down upon said partition, said element being provided immediately above said partition with at least one lateral aperture; 9. cup-like filter screen fitting into the casing and surrounding said inverted cup-like element with circumferential clearance thereabout, above the lateral aperture, through which screen the fluid is obliged to pass; a closure element constrained to axial movement by the cup-like element, said closure element having a disc normally seated over the large area portion of said port and a piston portion normally engaged within the smaller area portion of said port; and spring means influential upon said closure element for maintaining it with its disc and its piston portion normally positioned as aforesaid for capacity to yield upon development of back pressure in the outlet passage.
2. A by-pass valve characterized as in claim 1, wherein the piston portion of the closure element has a terminal taper.
References Cited in the file of this patent UNITED STATES PATENTS Switzerland Feb. 1,