US3521819A - Valved ejector - Google Patents

Description

July 28, 1970 D. JOHNSTON VALVED EJECTOR 2 Sheets-$heet 1 mm .N

mm ON Filed April 1. 1968 INVENTOR. I oouams JOHNSTON I III:

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VALVED EJEC'I'OR Filed April 1. 1968 2 Sheets-Sheet 2 FIG. 5

INVENTOR. DOUGLAS JOHNSTON United States Patent 3,521,819 VALVED EJECTOR Douglas Johnston, Decatur, Ala., assignor to Continental Oil Company, Pouca City, Okla., a corporation of Delaware Filed Apr. 1, 1968, Ser. No. 717,774 Int. Cl. 1305b 1/08 US. Cl. 23999 Claims ABSTRACT OF THE DISCLOSURE An ejector device is disclosed which receives liquid from a high pressure source, accumulates the liquid until its volume has built up sufficiently to compress an accumulator spring and, after taking up lost motion, a lifter spring, at which time a valve is snapped open to a detent position; when a given volume of liquid has been discharged through the valve, a return spring overcomes the detent and snaps the valve shut, at which time the cycle is repeated.

DISCLOSURE OF INVENTION This invention relates to a device for periodically ejecting slugs of liquid under pressure.

U.S. Pat. 3,012,526 to Baldwin et al., issued Dec. 12, 1961, discloses method and apparatus for injecting liquids into the soil whereby elongated consolidated slugs of liquid are propelled at high velocity so that the unconfined slugs are caused to penetrate the soil while substantially intact and before breaking up to any considerable degree. The present invention relates to improved apparatus useful in carrying out the invention claimed therein. 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 of a preferred embodiment of the present invention;

FIGS. .2 and 3 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. 1;

FIG. 5 is a section of an inlet strainer useful in conjunction with the device of FIG. 1; 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 inlet opening 10, from which it passes by way of ports 11 and 12 to chamber 13. The liquid produces hydraulic pressure which acts to move piston 14 outwardly of the chamber. Piston 14 acts directly on cup 15 and accumulator spring 16, compressing the latter, until such time as the valve lifter spring 17 is carried by the inner or lower portion 18 of the piston into engagement with the protrusion 19 on valve rod 20. Continued outward motion of piston 14 does not immediately lift valve rod 20' from the valve seat area 21, 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 spring 17 as well as of spring 16. 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 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 3,521,819 Patented July 28, 1970 held in an open position by virtue of detent balls 23 engaging chamfer 24 on valve rod 20. The valve rod is held in the open position until such time as piston 14, urged inward by accumulator spring 16, compresses valve return spring 25 against protrusion 19 on valve rod 20 sufiiciently 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.

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 26 which is normally held in contact with a seating area 27 in passage 28 by ball seating spring 29. Should some malfunction occur, such as breaking off of protrusion 19 from valve rod 20 so that the discharge valve would remain closed, the continuing build-up of pressure in chamber 13 causes the piston assembly, including upper portion 14, to continue outward until ball 26 is unseated by the tip of rod 30. Pressure is thus vented by liquid passing from chamber 13 via ports 31 and passages 28 and 32 into upper chamber 33 and thence to the atmosphere via cap 34, which can for instance be a conventional oiler cup fitting with a lightly spring-loaded cap. When e.g. ammonia is the liquid being handled, the fog issuing from cap 34 provides an immediate visual indication of malfunction. Relief valve rod is provided with a length adjustment and adjustment lock nut 35 at its upper end. Its lower portion of intermediate diameter, at 36, is preferably of squared-01f cross-section to allow ample venting flow area through the upper end of passage 28. Upper chamber 33 is definde by upper housing 37 and closure 38, and serves primarily as a safety guard and to keep dirt from accumulator spring 16. Lower chamber 13 is defined by the lower housing 39 and its auxiliaries, and must resist maximum system pressure. U per piston assembly 14 is accordingly provided with packing 40, which is maintained in a compressed condition by packing spring 41 and spring retainer 42 at its inner surface, and by housing closure 43 at its outer surface; closure 43 also serves as a guide for upper piston assembly 14. It has been found that Rulon, a filled polytetrafluoroethylene, is an excellent packing material for high pressure service with anhydrous ammonia. 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 anti-friction inserts 44, also preferably of Rulon. The lower piston assembly is provided with a base 45, which serves dually as a support for valve lifter spring 17 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, and provided with ports 46 to allow free liquid flow into the hollow interior. Other parts, whose function is obvious, are upper return spring retainer pin 47, lower 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.

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 metal-to-metal 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 desirable.

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 10 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 clean-out plug 58, a male threaded outlet nipple 59 which can be threaded directly into accumulator inlet port 10, 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. 1. Orifice opening 22, nozzle body 52, and orifice tip 53 are as in FIG. 1, 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 pasageway 62 which serves to equalize pressure 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 in which the spring constants were about as follows: accumulator spring (16) 478#/in., valve lifter spring (17) 450#/in., valve return spring l5l#/in., and detent springs (50) about 2.75# to release. The diameter of upper piston 14 at its exit from the chamber, i.e. at packing 40, was 0.499 inch, and the orifice tip opening varied, in different experiments, from 0.031 to 0.094 inch. Valve seat area 21 was about 0.02 14 square inch, and the lost motion between the end of lifter spring 17 and protrusion 19 was 0.172 inch. This configuration produced a pressure of liquid at time of discharge of about 5800 p.s.i. In operation, the device was connected to a source of anhydrous ammonia under pressure and, with the source used, the ammonia flow rate was varied so as to effect from about 5 to about 800 cycles 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. 1

While particular embodiments of the invention have been described, it will be understood, of course, that the invention is not limited thereto since many modifications may be made, and it is, therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention.

The invention having thus been described, what is claimed is:

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

(a) an elongated housing having means to receive an inlet flow of said liquid,

(b) piston means axially reciprocable through one end of said housing and in fluid-sealing relationship therewith,

(c) first spring means external of said housing and connected to said piston means to be compressed by outward movement of said piston means,

(d) orifice means at the other end of said housing,

(e) valve rod means axially reciprocable within said housing between a first position in closing engagement with said orifice means and a second position withdrawn from said orifice means,

(f) detent means for yieldably retaining said valve rod means in said second position,

(g) second spring means internal of said housing and compressible, after lost motion, by relative axial movement of said piston means away from said valve rod means, and

(h) third spring means internal of said housing and compressible by relative axial movement of said piston means toward said valve rod means.

2. The device of claim 11 wherein each of said second and said third spring means are contained within an extension of said piston means, and are engageable with said valve rod means at a protruded portion thereof.

3. The device of claim 1 further including resilient annular guide means for centering said valve rod means with respect to said orifice means.

4. The device of claim 1 further provided with relief valve means comprising ball valve means in a hollow passageway in said piston means, said passageway communicating between the interior and the exterior of said housing, said ball valve means being moveable between a first position closing said passageway and asecond position opening said passageway, and limit means for moving said ball valve means from said first to said second position upon axial movement of said piston means beyond a predetermined location.

5. The device of claim 1 further provided with strainer means connected to said means to receive.

References Cited UNITED STATES PATENTS 2,930,334 3/1960 Marron et al ll16 3,012,526 1.2/1961 Baldwin et al. 111-6 3,123,070 3/ 196.4 Kath.

M. HENSON WOOD, JR., Primary Examiner J. J. LOVE, Assistant Examiner US. Cl. X.R. 111-6; 239-533

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