US3598323A - Pressure accumulator - Google Patents

Abstract

An ejector device is disclosed which receives liquid from a high-pressure source, accumulates the liquid until its volume is built up sufficiently to compress a portion thereof and, after taking up lost motion, a lifter spring, at which time a valve is snapped open to a detent position; when a predetermined volume of liquid has been discharged, a return spring snaps the valve shut to complete the cycle.

Description

I United States Patent [72) Inventors Douglas Johnston; 56] References Cited Harold S60 Parker, both of Decatur, A18. UNITED STATES PATENTS [21] Appl. Nov 843,431 122] Filed July 22,1969 2,930,334 3/1960 Marron et a]. 111/6 [45] Paemed Aug 3,012,526 12/1961 Baldwin etal. 111/6 [73] Assignee Continental Oil Company Primary ExaminerM. Henson Wood, .Ir.

Pouca City, Okla. Assistant Examiner-J0hn J. Love Attorneys .loseph C. Kotarski, Henry H, Huth, Jerry B. Peterson, William A. Mikesell, Jr. and Carroll Palmer [54] g'gfiii'ff fifigr ABSTRACT: An ejector device is disclosed which receives liquid from a high-pressure source, accumulates the liquid {52] U.S.Cl 239/533, until its volume is built up sufficiently to compress a portion 239/99 thereof and, after taking up lost motion, a lifter spring, at [51] Int. Cl B!) 1/30 which time a valve is snapped open to a detent position; when [50] Field of Search 239/99, a predetermined volume of liquid has been discharged, a

100,533;lll/6 return spring snaps the valve shut to complete the cycle.

PATENTEU AUG] 0197! SHEET 2 [IF 2 INVENTOR.

DOUGLAS JOHNSTON HAROLD s. PARKER (Jo M a. m @w 6) ATTORNEY PRESSURE ACCUMULATOR CROSS-REFERENCE TO RELATED APPLICATION This application is an improvement upon the invention dis- DISCLOSURE OF INVENTION This invention relates to a device for periodically ejecting slugs of liquid under pressure.

U.S. Pat No. 3,0I2,526 to Baldwin et al., issued Dec. I2,

carrying out the invention disclosed in the Baldwin et al.

patent. The present invention relates, to improved apparatus useful in carrying out the invention of the Baldwin et al. patent. The device of this invention has additional uses, which will be discussed later herein.

The invention will be best understood by reference to the drawing, in which:

FIG. 1 is a longitudinal section, partially in elevation, of a preferred embodiment of the present invention;

FIGS 2, 3, and 7 are cross sections taken at the indicated locations on FIG. 1;

FIG. 4 is a longitudinal section of a portion of the device of FIG. 1, taken at right angle to the section of FIG. I;

FIG. 5 is a section of an inlet strainer useful in conjunction with the device of FIG. I; and

FIG. 6 is a detail of the lower tip of the FIG. 1 device.

Referring now to FIG. 1 in detail, the general operation of the device will be explained, followed by a more explicit consideration thereof. Liquid from a source not shown is introduced into the device by way of an inlet opening 10, from which it passes by way of ports 11 and 12 to a chamber 13 defined by a housing 39. The liquid then continues from chamber 13 by way of passages 15 and 16 and past ball valves 26 and 27 and their associated seats 28 and 29 respectively into a second chamber 30, defined by a housing 43. As the pressure in chamber 30 increases, a piston 31, which has been holding ball valve 27 off its seat 29 against the compression of spring 32, is now urged outwardly of chamber 30 against a spring seat 33 and a spring 35. when the pressure in chamber 30 has reached a desired predetermined value, i.e. when piston 31 has been urged outwardly far enough to allow ball valve 27 to seal on seat 29, flow into chamber 30 stops. As additional liquid is fed into the device, the pressure in chamber 13 continues to rise above that in chamber 30, which causes a piston 14 to move away from chamber 13 and toward chamber 30, thus compressing the liquid in chamber 30. Piston I4 continues this movement until such time as a valve pressure differential between chamber 30 and the pressure outside orifice 22, compresses a valve return spring 25 against protrusion 19 on valve rod sufficiently to overcome the resistance offered by detent balls 23. At this time, valve rod 20 is quickly snapped shut by the energy stored in return spring 25, thus preventing drawing of the final portion of the issuing liquid slug. Enlarged head 72 on piston 14 prevents overtravel during the snap closing.

Piston 31, spring 35, stop rod 38, and the various parts as'- sociated therewith are housed in a guide 47.

The typical operation and main components of the device having been described, attention will now be directed to refinements thereof. First, there will be described a relief valve system which functions to vent pressure from the chamber in the event of some malfunction of the device. The relief system comprises a ball valve 36 urged against a seat inside piston 31 by a spring 37, a stop rod 38 adjustably mounted in an end cap 40, and a capped vent 34. Should the pressure in chamber 30 become too high, piston 31 is urged outwardly far enough to cause stop rod 38 to unseat ball valve 36, venting liquid in chamber 30 through ports 41 in piston 31, past ball valve 36, and out vent 34, which can for instance be a conventional oiler cup fitting with a lightly spring-loaded cap.

lifter spring 17 is carried by an inner or lower portion 18 of piston I4 into engagement with a protrusion 19 on a valve rod 20. Continued outward motion of piston 14 does not immediately lift valve rod 20 from the valve seat area 2l, since the internal hydraulic pressure is also acting on valve rod 20, although over a much smaller area than that of piston 14. Rather, continued outward movement of piston 14 now causes compression of a spring 17 as well as of the liquid in chamber 30. At such time as the outward hydraulic force on valve rod 20 is overcome, valve rod 20 is quickly pulled inwardly off its seat area 21 by spring 17. This allows discharge of liquid under the prevailing hydraulic pressure from an orifice 22, with the quick lift provided by spring 17 preventing drawing of the liquid jet. When valve rod 20 is lifted off its seat, it is held in an open position by virtue of detent balls 23 engaging a chamfer until such time as piston 14, urged toward chamber 13 by the Adjustment of relief pressure in chamber 31 is effected by moving stop rod 38 in conjunction with a locknut 42, and will of course be dependent also on the spring constant of spring 35 and the cross-sectional area of piston 31.

The lower portion 18 of the piston assembly is preferably square in cross section, as shown in FIG. 2, to allow sufficient flow passage area for liquid; this assembly is provided with antifriction inserts 44, preferably of Rulon, a filled polytetrafluoroethylenc. The lower piston assembly is provided with a base 45, which serves dually as a support for valve lifter spring I7 and as a guide for valve rod 20. Valve rod 20 is preferably hollow at its upper end to reduce its inertia during snap action, andprovided with portion 46 to allow free liquid flow into the hollow interior. Other parts, whose function is obvious, are return spring retainer washer 48, detent ball adapters, springs, and retainers 49, 50, and 51, nozzle 52, nozzle tip 53, nozzle retainer nut 54, ports 64 and 65, and various gaskets, not numbered. 1

It will be noted thathousing 39 terminates a short distance into housing 43, for ease of construction. l-lowevenhousing 39 is in effect extended further into housing 43 by virtue of a plug 66, which contains a portion of passage chamber 30 at all times by virtue of passages 67 through its end, as shown in FIG. 7. Capscrews 68 secure plug 66 to housing 39. Passage I6 and seat 28 are carried by an extension 69 of plug 66. Extension 69 and guide 47 are connected by a sleeve 70, again for ease of construction and assembly. The function of the various packings, packing nuts, and packing springs within guide 47, plug 66, and body 43 are obvious. A spacer 71 is provided between ball valves 26 and 27 to prevent crushing of spring 32.

Additional features of the accumulator include a ball check valve 26 and seat 28, previously mentioned, whose function it is to prevent loss of fluid from chamber 30 in the event of drastic pressure loss from chamber 13. A ball check valve 72 and its seat 73 and spring 74 serve this same latter function. Finally, a ball check valve 75 and its associated spring, along with an adjustable rod 76, serve to relieve excessive pressure in chamber 13, caused e.g. by stoppage of orifice 22, by driving piston 14 far enough into chamber 30 to cause rod 76 to unseat ball valve 75 and allow the excessive pressure in chamber 13 to flow into plug 66 through ports 67 into chamber 30, and thence by the previously described relief operation of rod 38 and ball valve 36, out vent 34.

The materials of construction of the device will depend upon the kinds of liquids which are contemplated for use therein; for anhydrous ammonia, carbon steel is quite suitable. Where there is a metaI-tmmetal slide fit, such as where valve rod 20 passes through the lower end of the lower housing by the detent balls, chrome plating of one part, or some other treatment to prevent galling, is desireable.

In addition to being extremely useful for injecting a fertilizer liquid such as anhydrous ammonia into the soil, subject device is quite useful for fogging. It has been found that when a gun device of this invention is aimed into the air and charged with an aqueous liquid, the issuing liquid slug passes compactly through the air for some distance and then breaks into a very fine and uniform fog. Depending on the vapor pressure of the liquid and the pressure of the discharged slug, this distance can be from a few feet to as much as 25 to 50 feet. Thus, solutions of insecticide etc. can be dispersed nicely in an orchard area.

Two additional desirable features of this invention are shown in FIGS. 5 and 6 respectively. FIG. 5 comprises a strainer which threads directly into inlet port 110 of the accumulator device, and serves to remove finely divided solids which might otherwise cause wear and abrasion to the working parts of the device. The filter assembly comprises a body or housing 55 with a female-threaded inlet port 56, a cylindrical strainer screen 57 open at both ends, a cleanout plug 58, a male-threaded outlet nipple 59 which can be threaded directly into accumulator inlet port I0, an outlet-nipple-retaining nut 60 which also acts as a union, and suitable gaskets not numbered. FIG. 6 comprises a detail of the orifice tip of the accumulator of FIG. I. Orifice opening 22, nozzle body 52, and orifice tip 53 are as in FIG. I, as is the valve-rod-seating area 21. The features to be shown here are friction insert 61, which comprises an insert of a deformable material such as nylon and serves to prevent the orifice tip 53 from unthreading from body 52, and passageway 62 which serves to equalize ressure on the face of and behind guide 63. Guide 63 is an insert, preferably of nylon, which centers the descending valve rod with respect to seating area 21.

A device as shown in FIG. 1 was built and tested using anhydrous ammonia as the liquid. The spring constant" of anhydrous ammonia in chamber 30, against which piston [4 works, is about I59 lb./in. for the size of piston 14 used. Other spring constants were approximately as follows: lifter spring 17 450 lb./in., valve return spring I51 lb./in., shutoff spring 35 780 lb./in., and detent springs 50 about 40 lb. to release. The efiective diameter of piston I4 was 0.50 inches, of piston 31 0.203 inches, and of orifice 22, in various experiments, from 0.040 to 0.078 inches. Area of valve seat 21 was about 0.0144 square inches, and the motion" between the end of lifter spring 17 and protrusion 19 was about 0.172 inch. This configuration produced a liquid pressure at time of discharge of about 4800 p.s.i. The ammonia flow rate was varied so as to effect from about 20 to about 5l5 cycle of the accumulator per minute. The ammonia liquid slugs were cleanly ejected, with no discernible drawing," and penetrated the soil from a distance of a few inches to 10 or more inches, depending on soil type.

Although this invention has been described with respect to particular embodiments thereof, it is not to be so limited, as changes and modifications may be made therein which are within the spirit and scope of the invention as defined by the appended claims.

What we claim is:

l. A hydraulic device for intermittently ejecting slugs of liquid under pressure which comprises:

a. a first elongated chamber having means to receive an inlet flow of said liquid;

b. a second chamber adjacent to said first chamber and having a wall in common therewith;

c. piston means through said wall reciprocable in said first and said second chambers;

d. passage means communicating between said first and said second chambers;

e. valve means responsive to an increase in pressure within said second chamber to close said passage means;

f. orifice means communicating with said first chamber;

g. valve rod means axially reciprocable within said first chamber between a first position in closing engagement with said orifice means and a second position withdrawn from said orifice means; I h. detent means for yieldably retaining said valve rod means in said second position;

i. coupling means for connecting said piston means with said valve rod means with lost motion;

j. first spring means compressible by relative axial motion of said piston means away from said valve rod means; and

k. second spring means compressible by relative axial motion of said piston means toward said valve rod means.

2. The device of claim I further provided with pressure relief means comprising:

a. second piston means communi'ating with said second chamber;

b. third spring means urging said second piston means inwardly of said second chamber; and

c. second valve means in a wall of said second chamber actuable by outward movement of said second piston means therefrom.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 598 323 D d August 1971 Douglas Johnston et a1. Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 46, after "passage" insert 15. The interior of plug 66 is at the same pressure as is Column 3, lines 36-39 should be canceled and the following inserted instead therefore works, is about 159 #/in. for the size of piston 14 used. Other spring constants were approximately as follows: lifter spring 17 450 #/in. valve return spring l5l#/in. shut-off spring 780 #/in. and detent springs about 40# to release. line 43, 't""mot ionh" should read "lost motion" Signed and sealed this 4th day of April 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents ORM l m-1050 -69! USCOMM-DC 50376-P59 U 5 GOVERNMENT PRINYING OFHCE I9690-366ai36

Claims (2)

1. A hydraulic device for intermittently ejecting slugs of liquid under pressure which comprises: a. a first elongated chamber having means to receive an inlet flow of said liquid; b. a second chamber adjacent to said first chamber and having a wall in common therewith; c. piston means through said wall reciprocable in said first and said second chambers; d. passage means communicating between said first and said second chambers; e. valve means responsive to an increase in pressure within said second chamber to close said passage means; f. orifice means communicating with said first chamber; g. valve rod means axially reciprocable within said first chamber between a first position in closing engagement with said orifice means and a second position withdrawn from said orifice means; h. detent means for yieldably retaining said valve rod means in said second position; i. coupling means for connecting said piston means with said valve rod means with lost motion; j. first spring means compressible by relative axial motion of said piston means away from said valve rod means; and k. second spring means compressible by relative axial motion of said piston means toward said valve rod means.

2. The device of claim 1 further provided with pressure relief means comprising: a. second piston means communicating with said second chamber; b. third spring means urging said second piston means inwardly of said second chamber; and c. second valve means in a wall of said second chamber actuable by outward movement of said second piston means therefrom.

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