US3803988A

US3803988A - Diesel fuel primer pump

Info

Publication number: US3803988A
Application number: US00355599A
Authority: US
Inventors: T Orr
Original assignee: OVICO
Current assignee: OVICO
Priority date: 1973-04-30
Filing date: 1973-04-30
Publication date: 1974-04-16
Anticipated expiration: 1991-04-16

Abstract

A diesel fuel primer pump includes a piston assembly and cylinder having a filter media for air exhausted from the cylinder and biasing means between the actuating handle for the piston and the cylinder to resist vibration of the primer pump when it is not in operation.

Description

v 0 I Muted States Patent 1 91 1111 3,803,988 Orr 1 1 Apr. 16, 1974 1 DIESEL FUEL PRIMER PUMP 1,382,705 6/1921 Wood 277 112 1,453,270 5/1923, Burton 417/561 [75] Inventor: Green-519mg 1,486,600 3/1924 Nuhring 417/561 73 Assigneez Ovlco, Greensburg p 2,185,146 12/1939 Edwards 92/129 3,213,760 10/1965 Carr 92/85 [22] Filed: Apr. 30, 1973 [21] APP] No; 355 599 Primary ExaminerWilliam L. Freeh Attorney, Agent, or Firm -Webb, Burden, Robinson &

. Webb [52] U.S. Cl 92/85, 92/168, 277/107, 277/108, 277/112, 417/571 511 1111.131. F16j 15/18, F04b 21/04 1 ABSTIFACT 58 Field 61 Search 92/168; 277/107, 108, 112; A dlesel fuel prlmer p Includes a Plston assembly 4 7 57 5 and cylinder having a filter media for air exhausted from the cylinder and biasing means between the actu- 56 References Cited ating handle for the piston and the cylinder to resist UNITED STATES PATENTS vibration of the primer pump when it is not in operat 148,285 3/1874 Cornelius 277/107 Ion 1,365,824 1/1921 Goldberg 417/501 8 Claims, 3 Drawing Figures PATENTEDAPR 16 m4 3.803 988 SHEET 1 BF 2 P I I I I I I I" DIESEL FUEL PRIMER PUMP This invention relates to a diesel fuel primer pump and particularly to a hand operated piston type pump for priming diesel engines such as those used on heavy earth working equipment such as bulldozers.

Primer pumps have long been used with diesel engines as auxiliary devices to promote starting of engines. A primer pump may be placed in a bypass fuel line between the main fuel supply and the engine in parallel with the main electrical fuel pump. The purpose of the primer pump is to pump sufficient fuel from the supply tank to the engine and particularly to the injectors of a diesel engine to enable the engine to be cold-started without excessive use of the electrical system which normally operates the fuel pump.

A well-known primer pump comprises a cylinder having a flange on one end which is adapted for stationarymounting to equipment or to a vehicle. The flange includes inlet and outlet ports. The inlet port is connected to a portion of a diesel fuel line from the main fuel supply. The outlet port is connected to a portion of the line to the diesel engine injectors. There is a valve between the inlet and outlet ports which is controlled by a hand operated piston which is reciprocable in the bore of the cylinder. The opposite end of the cylind'er is usually closed except for an opening for the piston rod to which the actuating handle is attached and an opening for relieving the air pressure from the chamber behind the piston. In some primer pumps the opening for the piston rod is substantially larger than the rod and air is bled through the same opening on the rearward stroke of the piston. In other primer pump designs, separate breather plugs or check valves are employed to relieve the air.

In present pump designs, especially primer pumps for diesel engines used on heavy duty equipment, several problems have occurred. One problem has been that the openings or breather plugs or valves for relieving air from the rear chamber of the cylinder have become plugged with dirt, oil, grease and other contaminants usually associated with heavy duty engines and accordingly the primer pump operation has been made more difficult or the primer pump has been rendered completely inoperable since the piston could not be withdrawn in the cylinder due to the pressure behind it.

A second problem which has developed with primer pumps on heavy duty equipment is that the pumps have become unlocked due to excessive vibration of the equipment and have permitted fuel to flow through the primer pump even when the main fuel pump is operating. This cannot be tolerated in a diesel fuel system where for example, the pump is used to protect pressure gauges from wear and to prevent fuel from passing into parts of the fuel system where it is not wanted.

I have invented a diesel fuel primer pump which overcomes these problems and has additional features which will be apparent from the following disclosure. Briefly, my primer pump includes the conventional piston-cylinder arrangement for passing diesel fuel from the main supply to the engine through a valve which isoperated by the piston. The piston rod carries filter media for permitting air to leave the chamber of the cylinder behind the piston and for preventing contaminants from entering the chamber. The primer pump also includes biasing meansdisposed onthe piston rod between the actuating handle and locking mechanism secured to the pump cylinder for preventing unlocking of the piston assembly under excessive vibration.

These. and other advantages of the invention will become apparent from the disclosure taken with the accompanying drawings in which:

FIG. 1 is an elevation view of a primer pump according to the invention;

FIG. 2 is a cross-sectional view taken along the central axis of FIG. 1; and

FIG. 3 is an exploded cross-sectional view taken along the longitudinal axis of the pump of FIG. 1.

Referring to the drawings, a diesel fuel primer pump 1 comprises a cylinder 2 and a piston assembly 3. A flange 4 having threads 5 is secured to cylinder internal threads 6. The flange has holes 7 through which suitable fasteners such as bolts may be placed to mount the pump on equipment or on a vehicle (not shown). As shown in FIG. 2, the flange has an inlet 8 and an outlet 9 for connection to portions of a diesel fuel line. The

Y inlet and outlet are opened and closed by the piston assembly which comprises a reciprocable piston 10 having a central movable needle 11 which fits into the inlet to be inserted into the bore of the cylinder during assembly without damaging the O-rings on the threads 19.

The closure is adapted to be threadably secured to the end of the cylinder by a tool applied to the hexagonal portion 22 of the closure. The bore of the closure has a circular end taper 23, of approximately 15.

The piston assembly comprises the piston 10 having a threaded bore portion 24 which engages threads 25 on an end 26 of the piston rod 15. The piston rod is threaded into the piston until the piston abuts shoulder 27 of the piston rod. There is a cylindrical recess in the end 26 of the rod which accommodates a part of a coil spring 28 which is biased between the needle and the end of the piston rod.

A pair of porous metallic rings 29, separated by a non-metallic dust sealing ring 30, for example of felt material, are mounted on the piston rod 15. The outer diameter of the sealing ring 30 is smaller than the outer diameter of the porous rings 29; for example, the radius of sealing ring 30 is about one-half the radius of the porous ring 29 which is only slightly smaller in diameter than the bore of the closure into which it fits.

The rings are secured in the closure by a gland 31 which has external threads 32 which engage internal threads 33 of the closure. The wrench portion 34 of the gland includes a slight taper 35 of approximately 15 for example, which engages the taper 23 on the closure preventing the closure from being torqued too much and preventing the filter media from being over compressed and ruined.

The gland also includes a locking mechanism which, when the pump is disengaged, locks the piston in position closing the inlet and outlet. The locking mechanism comprises an internal groove 36 and two axial recesses 37 extending from face 38 of the gland which permit a pin 39 in the piston rod to enter groove 36. After the pin is in the groove, the rod is turned 90 to cause the pin to seat in holes 40 which are drilled into the gland in a wall 41 of the wrench head (FIG 1).

A coil spring 42 surrounds the rod between the pin 39 and the handle 17. When the handle is aligned with the recesses 37 and pushed inwardly to engage the pin in groove 36, the spring is compressed. After the handle and rod are turned 90 and released to seat the pin in the holes 40, the compression of the spring maintains the piston assembly in locked position and effectively resists vibration which has worn and ultimately destroyed locking pins used in prior primer pumps.

The operation of the pump is as follows. If it is desired to prime the engine with fuel, the handle 17 is depressed against the spring 42 and turned one-fourth turn to align the pin 39 with the gland recesses 37 and release the lock. The handle is pulled back moving the piston in the cylinder 2 to draw fuel through the primer pump and then pushed forward to apply positive pressure to the fuel to force it toward the engine. The cycle is repeated as many times as necessary to insure sufficient fuel at the engine injectors for starting. Of course, if there is any air in the fuel lines, the lines may be disassembled at the injector stop cocks and the air bled off at that point under positive pressure of the primer pump.

When the handle is pulled back, air must be relieved from the cylinder chamber behind the piston. In my primer pump, the air passes through the porous metallic rings and, since the sealing ring is compressed between the porous rings by the gland, through a substantial portion of the sealing ring which is axially expanded under the compression.

On the forward stroke of the piston assembly, air pulled into the chamber behind the piston often carries with it contaminants which have clogged relief air passages in prior desgins. In my pump, the filter media are substantially remote from the outside of the pump and are within the closure. The minimum air which may enter the closure through the bore of the gland and along the piston rod is trapped by a porous metallic filter ring. Similarly, on the return stroke, air in the chamber passes through a porous metallic filter ring. In each case the dust sealing ring is substantially isolated from any contaminants.

Preferably, the metallic filter rings are made of porous sintered bronze material. These rings are commercially available. Although they have been previously used for filtering hydraulic fluid from a ram chamber, as in U.S. Pat. No. 3,601,01 I, such rings, insofar as I am aware, have never been used for the purpose I have disclosed herein. I have found such rings to be particularly suitable in my invention.

My primer pump incorporates a number of advantages and is especially suitable for use under'rugged circumstances, such as in'heavy off-highway construction equipment, where excessive dirt, corrosion, contaminants and vibration are a major source of equipment malfunction and failure.

Having described a preferred embodiment of my invention, it may be otherwise embodied within the scope of the appended claims.

I claim:

1. A diesel fuel primer pump comprising a cylinder having a reciprocable piston assembly within the bore of the cylinder, means on one end of the cylinder for mounting the pump and including an inlet and outlet for fuel, the piston assembly including a piston having means for opening and closing the inlet and outlet and a piston rod attached to the piston, a closure secured to the other end of the cylinder, the piston rod extending through the closure and having a handle on the extending end, filter media on the piston rod within the closure, a gland secured to the closure to compress the media, means for locking the piston rod to the gland comprising a pin in the piston rod and engageable with the gland and biasing means between the handle and the pin for retaining the piston rod in locked position under vibration of the pump.

2. A diesel fuel primer pump as set forth in claim I wherein the filter media comprise a pair of porous metallic rings mounted on the piston rod and separated from each other by a non-metallic sealing ring, the diameter of the filter rings being greater than the diameter of the sealing ring to permit air exhausted from the pump cylinder to pass through the filter media to atmosphere.

3. A diesel fuel primer pump as set forth in claim 1 wherein the biasing means comprises a coil spring.

4. A diesel fuel primer pump as set forth in claim 1 wherein the end of the cylinder opposite the mounting end is of greater diameter than the extend of the bore of the cylinder to permit the piston to be assembled in the cylinder without damage.

5. In a diesel fuel primer pump comprising a cylinder and a piston assembly which is reciprocable within the cylinder, the improvement in means for exhausting air from the cylinder above the piston comprising filter media including a pair of porous metallic filter rings separated by a non-metallic sealing ring mounted on a piston rod, the diameter of the sealing ring being smaller than the diameter of the filter rings to permit air to pass from the cylinder to atmosphere.

6. A diesel fuel primer pump as set forth in claim 5 and including the improvement in means for resisting vibration of the pump comprising biasing means disposed on the piston rod between a locking pin for locking the handle in position and the handle for actuating the piston.

7. A diesel fuel primer pump comprising a cylinder having a reciprocable piston assembly within the bore of the cylinder, gland means threadably secured in the closure, a piston rod for actuating the piston extending through the closure and through the gland, filter media disposed on the piston rod within the closure and adapted to be compressed within the closure by the gland, said filter media comprising a pair of porous sintered filter rings separated by a non-metallic sealing ring, said filter media permitting air from the cylinder above the piston to be exhausted through the filter media to atmosphere upon the return stroke of the piston assembly.

8. A diesel fuel primer pump comprising a cylinder having a piston assembly reciprocable therein, one end of said cylinder being closed and including a locking mechanism, said locking mechanism comprising a gland having an internal recess, a pin extending through the piston rod and adapted to enter said recess in the gland and to be rotated therein, a handle on the piston rod for rotating it within the gland, and a coil spring between the pin and the handle for biasing the gland and handle to force the pin against the recess to retain the locking mechanism against vibration of the primer pump.

UNITED STATES PATENT OFFICE I CERTIFICATE OF CORRECTION Patent: No. 3, 3, 938 D t d April lb, 1974 Inventor-(X) Thomas M. Orr

It is certified that error appears in the above-identified Patent and that said Letters Patent are hereby corrected as shown below:

On the first page of the patent on the'ii ne listing the Assignee:

-'--Ov'1co-- should read Orrc 0-- Column 3" ine 12 we-- shouldreadf-the-n' Co 1umn 3 Line 39' desg in s-- shod-ld read de signs v Signed and sealed this 3rdday of December 1974.

(SEAL) Attest: I e McCOY M. mason JR. Q C.-MARSHALL DANYN,

Atte'sting Officer Commissioner of Patents FORM po-wso (10-69) 7 1. USCOMM'DC and, Y i u. s eovznupzgn manna orric: mu o-su-ul,

Claims

2. A diesel fuel primer pump as set forth iN claim 1 wherein the filter media comprise a pair of porous metallic rings mounted on the piston rod and separated from each other by a non-metallic sealing ring, the diameter of the filter rings being greater than the diameter of the sealing ring to permit air exhausted from the pump cylinder to pass through the filter media to atmosphere.