WO2006079153A1

WO2006079153A1 - A fluid injector

Info

Publication number: WO2006079153A1
Application number: PCT/AU2005/001631
Authority: WO
Inventors: Ian Douglas Mcphee
Original assignee: Icm Holdings Pty Ltd
Priority date: 2004-10-22
Filing date: 2005-10-21
Publication date: 2006-08-03

Abstract

A fluid injector (11) having an actuating chamber (18), an injection chamber (37), a fluid outlet (45), a piston (31) movable relative to the chambers (18, 37), and passages (13, 15) for connecting the actuating chamber (18) to a supply of fluid to cause movement of the piston in opposite directions between a first advanced position and a second retracted position. Passages (29, 42, 43) provide communication between the actuating chamber (18) and injection chamber (37) when the piston (31) is approaching or is in its second position for charging the injection chamber (37) with fluid through the actuating chamber (18). Movement of the piston (31) away from the second position towards the first position causes fluid charged into the injection chamber (37) to be displaced therefrom and fluid to be supplied through the fluid outlet (45).

Description

A FLUID INJECTOR i

Technical Field

This invention relates to an improved injector and in particular to an injector for use in lubrication systems such as lubrication systems used in large size earthmoving equipment or other plant or machinery. Background Art

Lubrication systems are commonly used in large size earthmoving equipment for example drag lines and excavators as employed in mining operations to lubricate moving parts such as bushes, bearings or pins. The lubrication systems usually include more than one grease distribution system each of which includes a pump connected to a source of grease which supplies grease to a distribution block carrying a series of grease injectors. The grease injectors are connected to feeder lines for supplying grease to bearing, bushes, pins or other moving parts to be lubricated. The injectors may be operated at regular intervals to supply a charge of grease or other lubricant to the bearing, bushes or pins or other moving parts .

Current injectors which are used have a number of moving parts including piston members which are actuated to cause a volume of grease to be discharged from the injector into a feed line to the part of the machinery to be lubricated. Many injectors use a coil spring associated with the piston member which is compressed during the injection stroke of the piston and which then returns the piston member at the end of the injection stroke. To enable the piston members to be returned at the end of the injection stroke, the springs are required to be of a relatively large size or heavy duty and are therefore expensive. Injections may also incorporate valves such a ball valves or poppet valves which control the charging of the grease chamber and discharging of grease from the chamber. The use of a number of mechanical components means that the injections are subject to malfunction or wear. If an injector malfunctions or seizes up, grease will not be supplied to the moving part which will eventually lead to failure of the part. This then results in considerable costs in replacing the part and in machine down-time. Summary of the Invention The present invention aims to provide an improved injector which is particularly but not exclusively suited to use in lubrication systems which overcomes or alleviates one or more of the above disadvantages or which at least provides an alternative to known injectors. The present invention in a further aspect aims to provide an injector assembly for lubrication systems. In another aspect, the present invention aims to provide a lubrication system including at least one injector. Other objects and advantages of the invention will become apparent from the following description.

The present invention thus provides in one aspect,., a fluid injector having an actuating chamber, an injection chamber, a fluid outlet, piston means associated with and movable relative to said chambers, means for connecting said actuating chamber to a supply of fluid to cause movement of said piston means in opposite directions between a first advanced position and a second retracted position, and wherein movement of said piston means controls communication of said injection chamber with a source of fluid to be injected to enable said injection chamber to be charged with fluid and fluid' to be displaced from said injection chamber for supply of fluid through said fluid outlet.

The fluid supply typically comprises a fluid pump communicating with a source of fluid which typically comprises the fluid to be supplied by the injector such as a lubricant for example grease.

Preferably, communication means provide communication between the actuating chamber and the injection chamber and the injection chamber and the fluid outlet.

Preferably, the communication means provides communication between the actuating chamber and injection chamber when the piston means is approaching or is in its second position whereby the injection chamber may be charged with fluid through the actuating chamber. Preferably the injector includes an outlet chamber communicating with the fluid outlet.

Suitably the communication means provides for communication between the injection chamber and outlet chamber when the piston means is moved away from the first position. The communication means suitably includes a passage or passages in the piston means and wherein movement of the piston means controls communication of the passage or passages with the chambers.

The passage or passages suitably include a charging passage or passages communicating the actuating chamber and injection chamber when the piston means is in or approaches the second position.

The passage or passages may also include an outlet passage or passages adapted to communicate with the outlet chamber and wherein fluid in the injection chamber is forced through the outlet passage or passages into the outlet chamber when the piston means moves from the first position towards the second position. Preferably the outlet passage or passages is/are blocked from communication with the outlet chamber when the piston means is in or approaches the first position.

Preferably the passage or passages include/s a passage extending longitudinally of the piston means and further passages communicating with the longitudinally extending passage. The further passages suitably comprise a first passage communicating with the injection chamber, a second passage communicating with the actuating chamber when the piston is in or approaches the first position of the piston means and a third passage communicating with the outlet chamber when the piston means moves away from the first position. The further passages suitably extend transversely of the longitudinally extending passage. The injection chamber suitably comprises a chamber of annular cross section and defined between a reduced diameter portion of the piston means and a bore in which the piston means moves. The longitudinally extending passage suitably extends through the reduced diameter portion of the piston means and suitably the second and third passages are provided in the reduced diameter portion. Preferably the injection chamber is further defined between a fixed wall or member and a piston face movable with the piston means and the injection chamber reduces in volume when the piston means moves away from the first position causing the piston face to move towards the fixed wall or member.

Preferably the piston means includes a first piston movable in the actuating chamber and the connecting means suitably comprises means communicating with opposite sides of piston and adapted for communication with the fluid supply.

The injector suitably includes a first body part in which the actuator chamber is defined, a second body part in which the injection chamber is defined and a third body part in which the outlet chamber is defined. Preferably the first body part is engaged with the second body part and said second body part is engaged with the third body part, the body parts being longitudinally aligned. The body portions are suitably threadably engaged with each other.

Preferably, means are provided for selectively limiting the stroke of the piston means to vary the volume of the injection chamber. The stroke limiting means may comprise means which extend into the outlet chamber and in the path of movement of the piston means.

In another preferred aspect, the present invention provides a fluid injector assembly including at least one injector, said injector comprising a body mounted to a fluid manifold, each said body having an actuating chamber, an injection chamber, a fluid outlet, and piston means associated with and movable in said first and second chambers, said fluid manifold having first and second ports communicating with said actuating chamber and adapted to be connected to a supply of fluid to cause movement of said piston means in opposite directions between a first advanced position and a second retracted position, means providing communication between said actuating chamber and said injection chamber when said piston means is approaching or is in said second position whereby said injection chamber is charged with fluid through said actuating chamber, and wherein movement of said piston means away from said second position towards said first position causes fluid charged into said injection chamber to be displaced therefrom and fluid to be supplied through said fluid outlet.

A plurality of fluid injectors may be mounted to the fluid manifold in parallel with each other so as to operate simultaneously. The fluid injectors thus may be connected to respective parts of machinery to be lubricated.

In yet a further aspect, the present invention provides a lubrication system for lubricating a machinery part comprising a least one fluid injector as described above, a fluid pump, selectively operable valve means for connecting the pump to the actuating chamber to cause the piston means to move between the first and second positions and a least one fluid feed line connecting the fluid injector to the machinery part.

It will be noted that in the injectors described above, the fluid for causing movement of the piston means between the first and second positions and for supply to the injection chamber is provided from a common source which in a lubrication application comprises any fluid lubricant such as grease.

The term "fluid" as referred to above in reference to the material injected by the injector may comprise any fluid including viscous fluids such as grease. Brief Description of the Drawings

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein :-

Fig..1 is a side elevation view of a pair of injectors according to the invention; Fig. 2 is an end view of the injectors of Figs. 1 ;

Fig. 3 is an enlarged sectional view along line A-A of Fig. 2;

Fig. 4 is an enlarged sectional view of a single injector along line B-B Fig. 1;

Figs. 5 to 8 illustrate in sectional views the injector in different operational positions;

Fig. 9 illustrates in schematic view, the manner in which the , injectors are provided in a lubrication system associated with machinery to be lubricated; and Fig. 10 is a sectional view of an injector with the adjustment screw reset. Detailed Description of the Preferred Embodiment

Referring to the drawings and firstly to Figs. 1 and 2, there is illustrated a grease injector assembly 10 including a pair of side-by-side injectors 11 according to the present invention. The injector assembly 10 includes a mounting block which forms a fluid manifold 12 to which the injectors 11 are mounted. The mounting block 12 includes as shown in Figs. 3 and 4 first longitudinally extending fluid flow passage 13 which is intersected by a series of transversely extending passages 14 which communicate with each injector 11 as described further below. The mounting block 12 further includes a second longitudinally extending flow passage 15 from which a series of passages 16 extend, the respective passages 16 corresponding in number and spacing to the passages 14 and also communicating with respective injectors 11.

Each injector 11 includes an upper hollow body part 17 which has internal actuating/charging chamber 18 and which is secured to the mounting block 12 by means of a bolt 19 passed through a passage 14 and in threaded engagement with the body part 17. Seals 20 seal the body part 17 to the mounting block 12. Each bolt 19 includes an annular groove 21 and a transversely extending passage 22 communicating with the groove 21, the groove 21, when the bolt 19 is in position securing the body part 17 of the injector 11 to the mounting block 12, being aligned, and communicating, with the longitudinally extending flow passage 13. The bolt 19 also includes a longitudinally extending passage 23 which extends from the transverse passage 22 and opens to, the end of the bolt 19 so as to communicate with the chamber 18.

The body part 17 also includes a longitudinally extending flow passage 24 which opens through the upper end of the body part 17 and which when the body part 17 is secured to the mounting block 12 is aligned with a passage 16. At its opposite end, the flow passage 24 opens into the lower end of the body part 17 via a passage 25. The injector 11 additional includes a middle body part 26 having an axial extending bore 27 therethrough and a lower body part 28 also having an axial extending bore therethrough comprising an upper portion 29 of reduced diameter compared to the bore 27 and a lower outwardly stepped portion which defines an outlet chamber 30. A metering spool 31 is arranged for longitudinal sliding movement within the injector body parts 17, 26 and 28, the spool 31. having a piston 32 movable within the chamber 18 and dividing the chamber 18 into an upper part 18' and a lower part 18", an inwardly stepped intermediate portion 33 of similar cross section to and slidable within the bore 27 and a lower portion 34 of similar cross section to and slidable within the bore portion 29. The piston 32 is sealed to the chamber 18 by an 0-ring or other seal (not shown). Furthermore the piston 32 is provided with an annular recess 32' on its rear side which, when the piston 32 is in its lowermost position, is aligned with and communicates with the passage 25. ^"The junction between the portions 33 and 34 of the spool 31 defines an_. annular piston face 35. When the spool 31 is other than at the bottom of its stroke, an annular injection chamber 37 (see Fig. 4) is formed in the bore 27 between the piston face 35 and top end of the body part 28 and around the lower portion 34 of the spool 31.

An end cap 38 is threadably secured to the lower body part 28 of the injector 11 and supports a volume adjustment screw 39 threaded into the cap 38 and which is extendable into the outlet chamber 30. A lock nut 40 engaged with the volume adjustment screw 39 is provided to lock the adjustment screw 39 in a fixed position.

The spool 31 additionally includes a longitudinally extending passage 41 arranged centrally of the spool and extending along the lower portion 34 of the spool 31 and into the intermediate portion 33. The passage 41 is intersected by a first transverse passage 42 which opens through the intermediate portion 33 on opposite sides thereof, a second transverse passage 43 which opens through the lower portion 34 on opposite sides thereof adjacent the piston face 35 and a third transverse passage 44 also opening through the lower portion 34 on the opposite sides and adjacent the lower end thereof. The passages in the spool 31 effectively form a spool-type valve which controls communication between the respective chambers 18, 30 and 37.

The lower body part 28 additionally includes at its lower end an outlet port 45 communicating with the outlet chamber 30 through which fluid is forced from the injector 11 into say a feed line for supplying grease to a moving part of machinery. The outlet port 45 may be provided with a one-way valve to prevent leakage of grease from the injector 11.

The injectors 11 are typically used as shown in Fig. 9 in a grease lubrication system 46 for machinery 47, the lubrication system 46. comprising a grease pump 48 connected to a grease reservoir 49 and in a dual line system including a changeover valve

50 to the ports 51 and 52 of the series of injectors 11, the port 51 communicating with the flow passages 13 and the port 52 communicating with the flow passages 15. The injectors 11 are connected through feed lines 53 and 54 to various^' parts of the machinery 47 subject to wear such as pins, bearings or bushes which are required to be lubricated.

In use, grease is initially pumped from the pump 48 via the changeover valve 50 and port 51 to the flow passage 13 and thus through the annular groove 21 and passages 22 and 23 into the upper chamber part 18'. At the same time the other port 52 is connected through the valve 50 to the reservoir 49. The pressure of the grease applied to the chamber part 18' and thus to the piston 32 forces the spool 31 downwardly and thus the lower end 34 of the spool portion 31 into the outlet chamber 30 as shown in Fig. 5. Any grease in the chamber 37 will thus be displaced from the chamber 37 and forced through the passages 43, 41 and 44 into the chamber 30 and grease in the chamber 30 is forced through the outlet port 45 into a feed line 53 or 54 for supply to the part of the machinery 47 to be lubricated.

At the lower end of the stroke of the spool 31, the changeover valve 50 is operated to reverse the supply of fluid to the injectors 11 so that the pump 48 is now connected, to supply grease, to the port 52 and thus the passages 15 whilst the port 51 and thus passages 13 are connected to the grease reservoir 49. Operation of the pump 48 will thus cause grease to be supplied through the passage 24 and passage 25 to the annular recess 32' on the underside of piston 32 in the chamber 18 thereby causing the spool 31 to be moved upwardly as shown in Fig. 6 as the chamber part 18" is charged with grease. Grease in the chamber part 18' above the piston 32 is forced through the passages 23, 22 and 13 back to the grease reservoir 49. When the spool 31 reaches or approaches the upper end of its stroke, the upper transverse passage 42 is aligned or becomes aligned with and opens to the chamber part 18". Grease then pumped into the chamber part 18" through the passages 24 and 25 will then flow through the chamber 18" into passage 42 and along the longitudinally extending passage 41 and through the transverse passage 43 to fill the chamber 37 with grease as shown in Fig. 7. Grease also fills the longitudinally extending passage 41. In this position the lower transverse passage 44 is within the bore portion 29 and therefore blocked from communicating with the outlet chamber 30.

The changeover valve 50 is reversed at the top of the stroke of the spool 31 shown in Fig. 7 so that the passages 13 are then connected to the pump 48 and the passages 15 connected to the grease reservoir 49. Thus operation of the pump 48 will now apply grease to the chamber part 18' on the upper side of the piston 32 to cause the next downward stroke of the spool 31. In the downward stroke of the spool 31, the volume of the chamber 37 will contract as the piston face 35 moves towards the upper end of the body part 28. Further the upper transverse passage 42 becomes closed as it moves into the bore 27 and the lower transverse passage 44 moves out of the bore portion 29 to open to the outlet chamber 30.

As the chamber 37 reduces in volume, the grease therein is forced through the passage 43, the passage 41 and passage 44 into the outlet chamber 30 as shown in Fig. 8 and the lower end 34 of the spool 31 moves into the chamber 30. This will cause grease to be displaced from the outlet chamber 30 through the outlet 45 to the feed line 53 or 54 connected thereto to lubricate the part to which the feed line is connected. Any grease in the chamber part 18" below the piston 32 is forced back into the grease reservoir 49 through the passages 25, 24 and 15.

As shown in Fig. 10, to vary the volume of grease discharge from the injector 11 on each downward or charging stroke of the injector 11, the adjustment screw 39 may be screwed further into the chamber 30. to thereby limit the stroke of the spool 31. This therefore reduces the volume of grease received in the injection chamber 37 and therefore the volume of grease which can be discharged from the injection chamber 37 through the outlet 45.

In an alternative arrangement for varying the volume of grease discharged from the injector 11 on each stroke of the spool 31, the spool 31 at its upper end may be provided with one or more removable spacers which limit the upward movement of the spool 31 and therefore limit the maximum volume of the chamber 37. Other arrangements may also be provided for this purpose.

Any form of changeover valve 50 may be used for alternating the supply of grease to the passages 13 or passages 15. Typically a solenoid-actuated valve may be provided for this purpose which is operated automatically when the spool 31 reaches the limits of its stroke in opposite direction to reverse the flow of grease to or from the injectors 11.

Figs. 1 and 2 illustrate a pair of injectors 11 associated with a mounting block 12. Any number of injectors 11 however may be mounted on a common mounting block 12. The injector 11 described above is particularly suited for use in injection grease in a grease injection lubrication systems however it may be used in other applications for the injection of fluids.

The terms "comprising" or "comprises" or derivatives thereof as used throughout the specification are taken to specify the presence of the stated features, integers and components referred to but not preclude the presence or addition of one or more other feature/s, integer/s, component/s or group thereof.

Whilst the above has been given by way of illustrative embodiment of the invention, all such variations and modifications thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein defined in the appended claims.

Claims

1. A fluid injector having an actuating chamber, an injection chamber, a fluid outlet, piston means associated with and movable relative to said chambers, means for connecting said actuating chamber to a supply of fluid to cause movement of said piston means in opposite directions between a first advanced position and a second retracted position, and wherein movement of said piston means controls communication of said injection chamber with a source of fluid to be injected to enable said injection chamber to be charged with fluid and fluid to be displaced from said injection chamber for supply of fluid through said fluid outlet.

2. An injector as claimed in claim 1 and including means for providing communication between said actuating chamber and said injection chamber and said injection chamber and said fluid outlet.

3. An injector as claimed in claim 2 wherein said communication means provides communication between said actuating chamber and said injection chamber when said piston means is approaching or is in said second position whereby said injection chamber may be charged with fluid through said actuating chamber.

4. An injector as claimed in claim 2 or claim 3 and including an outlet chamber communicating with said fluid outlet.

5. An injector as claimed in claim 4 wherein said communication means provides for communication between said injection chamber and said outlet chamber when said piston means is moved away from the first position.

6. An injector as claimed in claim 5 wherein said communication means includes a passage or passages in said piston means and wherein said movement of said piston means controls communication of said passage or passages with said chambers.

7. An injector as claimed in claim 6 wherein said passage or passages includes a charging passage or passages communicating said actuating chamber and injection chamber when said piston means is in or approaches said second position.

8. An injector as claimed in claim 8 wherein said passage or passages include an outlet passage or passages adapted to communicate with said outlet chamber and wherein fluid in the injection chamber is forced through said outlet passage or passages into the outlet chamber when the piston means moves from the first position towards the second position.

9. An injector as claimed in claim 8 wherein said outlet passage or passages is/are blocked from communication with the outlet chamber when the piston means is in or approaches the first position.

10. An injector as claimed in claim 9 wherein said passage or passages includes a passage extending longitudinally of the piston means and further passages communicating with the longitudinally extending passage.

11. An injector as claimed in claim 10 wherein said further passages comprise a first passage communicating with the injection chamber, a second passage communicating with the actuating chamber when the piston is in or approaches the first position of the piston means and a third passage communicating with the outlet chamber when the piston means moves away from the first position.

12. An injector as claimed in claim 11 wherein said injection chamber comprises a chamber of annular cross section and defined between a reduced diameter portion of said piston means and a bore in which said piston means moves.

13. An injector as claimed in claim 12 wherein said longitudinally extending passage extends through the reduced diameter portion of the piston means and wherein said second and third passages are provided in said reduced diameter portion.

14. An injector as claimed in 13 wherein said injection chamber is further defined between a fixed wall and a piston face movable with the piston means and wherein said injection chamber reduces in volume when said piston means moves away from the first position causing the piston face to move towards the fixed wall.

15. An injector as claimed in any one of the preceding claims wherein said piston' means includes a first piston movable in the actuating chamber and wherein said connecting means comprises means communicating with opposite sides of piston and adapted for communication with said fluid supply.

16. An injector as claimed in any one of claims 4 to 15 and including a first body part in which the actuator chamber is defined, a second body part in which the injection chamber is defined and a third body part in which the outlet chamber is defined.

17. An injector as claimed in claim 16 wherein said first body part is engaged with the second body part and said second body part is engaged with the third body part, said body parts being longitudinally aligned.

18. An injector as claimed in any one of the preceding claims and including means for selectively limiting the stroke of the piston means to vary the volume of injection chamber.

19. A fluid injector assembly including at least one injector, said injector comprising a body mounted to a fluid manifold, each said body having an actuating chamber, an injection chamber, a fluid outlet, and piston means associated with and movable in said first and second chambers, said fluid manifold having first and second ports communicating with said actuating chamber and adapted to be connected to a supply of fluid to cause movement of said piston means in opposite directions between a first advanced position and a second retracted position, means providing communication between said actuating chamber and said injection chamber when said piston means is approaching or is in said second position whereby said injection chamber is charged with fluid through said actuating chamber, and wherein movement of said piston means away from said second position towards said first position causes fluid charged into said injection chamber to be displaced therefrom and fluid to be supplied through said fluid outlet.

20. A lubrication system for lubricating a machinery part comprising a least one fluid injector as defined in any one of claims 1 to 18, a fluid pump, selectively operable valve means for connecting said pump to said actuating chamber to cause said piston means to move between said first and second positions and a least one fluid feed line connecting said fluid injector to said machinery part.