DESC:FIELD OF THE INVENTION
[001] The present invention relates to a lubrication supply system. More particularly, the present invention relates to a lubrication supply system that prevents clogging due to particulate material in the lubricant.

BACKGROUND OF THE INVENTION
[002] Generally, in high temperature processes, liquid lubricants containing dispersed powder particles are used. The liquid lubricants are sprayed on to the required surface wherein on exposure to high temperatures, even when the liquid component of the lubricant evaporates, the powdered material sticks on to the surface, thus providing the required lubrication.
[003] For delivery of the lubricant to the concerned component, automatic lubrication delivery systems have emerged across diverse industries for precise and consistent delivery of the lubricant to the critical components. These automatic lubrication delivery systems integrate various mechanical and electromechanical components such as advanced positive displacement pumps, programmable controllers and a network of valves. Valve controlled dispensers leverage solenoid valves actuated by electronic controllers for regulation of lubricant flow rates. However, valve controlled dispensers face inherent challenges primarily related to valve clogging wherein the powdered or particulate material of the lubricant tends to get clogged in the small orifices of the valve.
[004] Particularly, in high temperature environments, the lubricants will necessarily contain a high concentration powdered material. In these environments, the solenoid valve controlled dispensers become clogged due to the powdered material as well as other solid contaminants. Clogging of the valves leads to irregular lubricant flow through these valves and impaired flow control, which leads to uneven distribution of the lubricant. Uneven distribution of the lubricant hampers machine performance potentially causing machine downtime, and requiring frequent maintenance.
[005] In addition to the valves, conventionally used diaphragm pumps which use reciprocating action of a diaphragm and suitable valves on either side of the diaphragm for displacing a liquid, are also prone to clogging when delivering liquid lubricants having particulate material and require regular maintenance.
[006] Hence there is a need in the art for a lubrication supply system which addresses at least the aforementioned problems.

SUMMARY OF THE INVENTION
[007] In one aspect, the present invention is directed towards a lubrication supply system. The lubrication supply system has a reservoir for storing lubricant, a compressed air input device for supplying compressed air, and a pump having a cylinder and a piston provided inside the cylinder. The piston is movable between a first position and a second position. The pump is fluidly connected to the reservoir at a bore end of the piston. A first solenoid valve is configured to receive compressed air from the compressed air input device and supply compressed air to a rod end of the piston. Herein, when the piston is in the first position, the lubricant moves into the cylinder at the bore end of the piston, and the first solenoid valve supplies compressed air into the cylinder at the rod end of the piston, thereby pushing the piston towards the second position and delivering the lubricant out of the cylinder at the bore end of the piston.
[008] In an embodiment of the invention, the lubrication supply system has an agitation tube fluidly connected with the reservoir. The agitation tube receives compressed air from the compressed air input device and supplies air to lubricant in the reservoir.
[009] In a further embodiment of the invention, the first position of the piston is a topmost position of the piston and the second position of the piston is a bottommost position of the piston.
[010] In a further embodiment of the invention, the pump has a return spring connected to the piston. The return spring is configured to push the piston towards the first position.
[011] In a further embodiment of the invention, the lubrication supply system has a first check valve, wherein the cylinder is fluidly connected to a reservoir through a first check valve.
[012] In a further embodiment of the invention, the lubrication supply system has a lubricant discharge tube being connected to the cylinder at the bore end of the piston.
[013] In a further embodiment of the invention, the lubrication supply system has a second check valve provided inside the lubricant discharge tube.
[014] In a further embodiment of the invention, the lubrication supply system has a second solenoid valve configured to receive compressed air from the compressed air input device and supply compressed air to the lubricant discharge tube.
[015] In a further embodiment of the invention, the lubrication supply system has an electronic control unit for electronically controlling the first solenoid valve and the second solenoid valve.

BRIEF DESCRIPTION OF THE DRAWINGS
[016] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 illustrates a schematic diagram of a lubrication supply system, in accordance with an embodiment of the invention.
Figure 2 illustrates another schematic diagram of the lubrication supply system with a piston in a first position, in accordance with an embodiment of the invention.
Figure 3 illustrates another schematic diagram of the lubrication supply system with the piston in a second position, in accordance with an embodiment of the invention.
Figure 4 illustrates another schematic diagram of the lubrication supply system, in accordance with an embodiment of the invention.

DESCRIPTION OF THE INVENTION
[017] The present invention is directed towards a lubrication supply system that eliminates the risk of clogging, particularly when dealing with highly viscous lubricants with suspended powder particles. The present invention thus ensures consistent lubrication and enhances safety by reducing the risk of machinery breakdowns, product quality issues, and associated safety hazards. The present invention owing to elimination of clogging risk, is capable of delivering various forms of liquids including high-viscosity, water-based lubricants with suspended particles, as well as other types of coatings or surface treatments. The present invention also provides precise volume control for minimizing lubricant wastage.
[018] The lubrication system of the present invention is capable of being incorporated in any machine or process requiring delivery of lubricant. Thus, in the present invention, the flow path of the lubricant is kept separate from the flow path of the compressed air, thereby preventing flow of the lubricant through valves having small orifices and ensuring flow of only compressed air through the valves having small orifices for lubricant delivery.
[019] Figure 1 illustrates a schematic view of the lubrication system 100 in accordance with an embodiment of the invention. As illustrated, the system 100 comprises a reservoir 110 for storing the lubricant. In an embodiment, the reservoir is made of a non-corroding material such as stainless steel or plastic. In an exemplary embodiment, the reservoir 110 is a 210-litre High Density Polyethylene (HDPE) barrel. The system 100 further comprises a compressed air input device 102 for supplying compressed air. In and embodiment, the compressed air input device 102 includes one or more of but not limited to an axial flow compressor, a centrifugal compressor, a reciprocating compressor or a rotary compressor.
[020] In an embodiment, the lubricant has dispersed particulate material. The lubricant is generally a water based lubricant. Since the lubricant consists of particulate material, the lubricant is prone to sedimentation as the suspended particulate material may settle on the bottom of the reservoir 110, and thus it is essential to keep the lubricant mixed with water in a liquid state. For this purpose, the system 100 has an agitation tube 112 fluidly connected to the reservoir 110. The agitation tube 112 receives compressed air from the compressed air input device 102 and supplies the air to lubricant in the reservoir 110 to keep the lubricant agitated and the particulate material sufficiently suspended in the lubricant.
[021] As further illustrated in Figure 1, the system comprises a pump 120. The pump 120 is a pneumatic cylinder comprising a cylinder 122. A piston 124 provided inside the cylinder 122. The piston 124 is provided such that a space inside the cylinder 122 on one side of the piston, say rod end of the piston 124 is completely fluidly sealed from the other side of the piston 124, say bore end of the piston 124. The piston 124 is configured to move between a first position and a second position. In an embodiment, the first position of the piston 124 corresponds to a topmost position of the piston 124 and the second position corresponds to the bottommost position of the piston 124. Figure 1 illustrates the piston 124 in the second position. The pump 120 further comprises a return spring 126 operably connected to the piston 124. As illustrated in Figure 1, when the piston 124 is in the second position, the return spring 126 is fully compressed, and is configured to push the piston 124 to return to the first position of the piston 124 where the return spring 126 is fully relaxed.
[022] The cylinder 122 of the pump 120 is fluidly connected to the reservoir 110 at the bore end of the piston 124. In an embodiment, the cylinder 122 of the pump 120 is fluidly connected to a reservoir 110 through a first check valve 128. The first check valve 128 allows flow of lubricant from the reservoir 110 to the cylinder 122 but blocks the flow of lubricant from the cylinder 122 to the reservoir 110. Thus, when the piston 124 is in the first position the lubricant moves from the reservoir 110 into the cylinder 122 to fill up the cylinder 122 at the bore end of the piston 124.
[023] Further, the cylinder 122 of the pump 120 is connected to a lubricant discharge tube 130 at the bore end of the piston 124, and the lubricant discharge tube 130 is configured to deliver the lubricant to requisite parts of any machine as required. A second check valve 132 is provided inside the lubricant discharge tube 130, which allows flow of lubricant from the cylinder 122 into the lubricant discharge tube 130 but does not allow return flow of the lubricant from the lubricant discharge tube 130 to the cylinder 122.
[024] As further illustrated in Figure 1, for delivery of the lubricant, the system 100 has a first solenoid valve 140. In an embodiment, the first solenoid valve 140 comprises a spool type control valve wherein movement of a spool of the spool type control valve is actuated by a solenoid as per requirement. The first solenoid valve 140 is connected to the cylinder 122 of the pump 120 at the rod end of the piston 124. The first solenoid valve 140 is configured to receive compressed air from the compressed air input device 102 and supply compressed air to the rod end of the piston 124. The compressed air from the first solenoid valve 140 exerts pressure on the rod end of the piston 124 and pushes the piston 124 into the second position. When the piston 124 moves into the second position, the lubricant at the bore end of the piston 124 is pushed out of the cylinder 122 and delivered through the lubricant discharge tube 130. Accordingly, the path for the lubricant and path for compressed air are kept separate, and the lubricant does not pass through the first solenoid valve 140, thereby preventing clogging in the first solenoid valve 140.
[025] In an embodiment, before the lubricant from the lubricant discharge tube 130 is supplied to various parts of the machine as required, the lubricant needs to be atomised. To facilitate this, in an embodiment, as further illustrated in Figure 1, the system 100 has a second solenoid valve 150. In an embodiment, the second solenoid valve 150 comprises a spool type control valve wherein movement of a spool of the spool type control valve is actuated by a solenoid as per requirement. The second solenoid valve 150 is configured to receive compressed air from the compressed air input device 102 and supply compressed air to the lubricant discharge tube 130. The second solenoid valve 150 is connected to the lubricant discharge tube 130 through a third check valve 152. The third check valve 152 allows flow of air from the second solenoid valve 150 to the lubricant discharge tube 130 but does not allow flow of air from the lubricant discharge tube 130 to the second solenoid valve 150. The compressed air from the second solenoid valve 150 mixes with the lubricant in the lubricant discharge tube 130 and pressurises a nozzle (not shown) connected at the end of the lubricant discharge tube 130, leading to atomisation of the lubricant, which is then supplied as per requirement.
[026] Figures 2 and 3 illustrate a schematic diagram of the lubrication delivery system 100 wherein the path of the compressed air is illustrated in dotted lines and the path of the lubricant is illustrated in solid lines. Figure 2 illustrates the piston 124 in the first position and the Figure 3 illustrates piston 124 in the second position. As can be seen in Figure 2, to facilitate and control the flow the compressed air, the compressed air input device 102 is connected to a manual ON-OFF valve 160 and a first flow control valve 162, wherein the first flow control valve 162 is configured to control a flow rate of the inlet air. In an embodiment, the first control valve 162 has a gauge of half inch. Thereafter, the compressed air from the compressed air input device 102 travels to the reservoir 110 for agitation as explained hereinbefore through a first inline flow controller 164. The first inline flow controller 164 controls the flow rate of air being supplied to the reservoir 110 for agitation. Further, since the piston 124 is in the first position, the lubricant moves into the cylinder 122 at the bore end of the piston 124. The flow of lubricant from the reservoir 110 to the cylinder 122 is achieved either through pressure differential or through a suction mechanism as per requirement. A second flow control valve 166 is provided between the reservoir 110 and the cylinder 122 for controlling the flow rate of the lubricant. In an embodiment, the second control valve 166 has a gauge of three-fourth of an inch.
[027] Generally, when the lubricant is stored in the reservoir 110 for a long time, a solid layer of lubricant is likely to be formed on walls of the reservoir 110. This film then gets delaminated and suspended into the lubricant and may hamper the characteristics of the lubricant. To prevent this, a suction strainer 168 is provided between reservoir 110 and the cylinder 122, which strains out the large particles of this delaminated film from the lubricant. As illustrated in Figure 2, when the piston 124 is in the first position, the lubricant flows from the reservoir 110 to the cylinder 122 though the second control valve 166, the suction strainer 168 and the first check valve 128. During this operation, the second check valve 132 is kept in an OFF position to prevent any flow of the lubricant directly from the reservoir 110 to the lubricant discharge tube 130, or from the lubricant discharge tube 110 to the cylinder 122. Any residual air in the cylinder 122 on the rod end of the piston 124 is released through a leakage port in the first solenoid valve 140.
[028] Further, as referenced in Figure 3, when the piston 124 is in the first position, the cylinder 122 is filled up with the lubricant at the bore end of the piston 124. Thereafter, for delivery of the lubricant, compressed air is to be supplied to cylinder 122 at the rod end of the piston 124. For this, the first solenoid valve 140 receives the compressed air from the compressed air input device 102 through a filter regulator 170, which filters the compressed air from any solid contaminants and also regulates the amount of compressed air being provided to the first solenoid valve 140. Thereafter, the first solenoid valve 140 is actuated and the first solenoid valve 140 supplies the compressed air to the cylinder 122 at the rod end of the piston 124, thus pushing the piston 124 towards the second position and the lubricant out of the cylinder 122. During this operation, the second check valve 132 is switched ON which ensures that the lubricant being pushed out of the cylinder 122 moves into the lubricant discharge tube 130, and the first check valve 128 ensures that the lubricant being pushed out of the cylinder 122 does not travel towards the reservoir 110. A second inline flow controller 172 is provided in the lubricant discharge tube 130 to further control the rate of flow of the lubricant in the lubricant discharge tube 130. Once the piston 124 is in the second position, the return spring 126 is compressed, and the spring force of the return spring 126 causes the piston 124 to return to the first position, whereby more lubricant flows from the reservoir 110 to the cylinder 122 for the next cycle.
[029] As further illustrated in Figure 4, once the lubricant is pumped into the lubricant discharge tube 130, the second solenoid valve 150 is actuated. The second solenoid valve 150 receives compressed air from the compressed air input device 102 and supplies the compressed air to the lubricant discharge tube 130. The compressed air then pressurises the nozzle connected to the lubricant discharge tube 130, which leads to atomisation of the lubricant. A third inline flow controller 174 is provided between the second solenoid valve 150 and the lubricant discharge tube for controlling the rate of flow from the compressed air from the second solenoid valve 150 to the lubricant discharge tube. Simultaneously, since the piston 124 returns to the first position, the lubricant travels from the reservoir 110 to the cylinder 120 as explained hereinbefore. As can be seen in Figures 2, 3 and 4, the paths of the lubricant (illustrated in solid lines) and the compressed air (illustrated in dotted lines) are kept separate.
[030] In an embodiment, the first solenoid valve 140 and the second solenoid valve 150 are electronically controlled by an electronic control unit. For example, when the lubrication supply system 100 of the present invention is integrated into an extrusion press, the electronic control unit actuates the first solenoid valve 140 and the second solenoid valve 150 in accordance with a position of a main ram of the extrusion press. For example, the first solenoid valve 140 for pumping the lubricant out of the cylinder 122 is actuated only when the control unit receives a signal in relation to the main ram reaching a rearmost position of the main ram. The lubrication supply system 100 of the present invention finds its application in industries such as metal extrusion, metal forming, automotive industries, industries involving heavy machineries, coating and surface treatment industries, metallurgy related industries, printing industries, mining industries and any other industry requiring controlled supply of lubrication.
[031] Advantageously, the present invention provides for a lubrication supply system wherein the path of the lubricant and the compressed air are kept separate, thereby ensuring that the lubricant does not have to travel through the elements having smaller orifices such as the solenoid valves/spool type control valves. This prevents clogging of the smaller orifices in solenoid valves/spool type control valves and any other such components. In the present invention, only compressed air passed through components with small orifices which infinitesimally reduces chances of clogging. Further, all the valves through which the lubricant passes, such as the second control valve, the first check valve and the second check valve can have large gauges since only lubricant passes through these valves. This ensures that clogging does not occur at any of these valves.
[032] Further, in the present invention, a pneumatic cylinder is used for pumping of the lubricant, in which compressed air remains on the rod end of the piston and the lubricant remains on the bore end of the piston. This eliminates the requirement of a diaphragm pump for pumping of the lubricant, which further reduces any chances of clogging. Due to the reduction in clogging, the lubricant can be supplied regularly and reliably in in accordance with the needs and requirements of the machine in which the lubrication supply system of the present invention has been incorporated.
[033] Furthermore, the prevention of clogging also ensures that the frequency of maintenance requirements of the solenoid valves and the pump remains low, thus bringing down the costs and bringing down the machine downtime.
[034] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.
,CLAIMS:WE CLAIM:
1. A lubrication supply system (100) comprising:
a reservoir (110) for storing lubricant;
a compressed air input device (102) for supplying compressed air;
a pump (120) having a cylinder (122) and a piston (124) provided inside the cylinder (122), the piston (124) being movable between a first position and a second position, the pump (120) being fluidly connected to the reservoir (110) at a bore end of the piston (124); and
a first solenoid valve (140) configured to receive compressed air from the compressed air input device (102) and supply compressed air to a rod end of the piston (124), whereby when the piston (124) is in the first position, the lubricant moves into the cylinder (122) at the bore end of the piston (124), and the first solenoid valve (140) supplies compressed air into the cylinder (122) at the rod end of the piston (124), thereby pushing the piston (124) towards the second position and delivering the lubricant out of the cylinder (122) at the bore end of the piston (124).

2. The system (100) as claimed in claim 1, comprising an agitation tube (112) fluidly connected with the reservoir (110), the agitation tube (112) receiving compressed air from the compressed air input device (112) and supplying air to lubricant in the reservoir (110).

3. The system (100) as claimed in claim 1, wherein the first position of the piston (124) is a topmost position of the piston (124) and the second position of the piston (124) is a bottommost position of the piston (124).

4. The system (100) as claimed in claim 1, wherein the pump (120) comprises a return spring (126) connected to the piston (124), the return spring (126) configured to push the piston (124) towards the first position.

5. The system (100) as claimed in claim 1, comprising a first check valve (128), wherein the cylinder (122) is fluidly connected to a reservoir (110) through a first check valve (128).

6. The system (100) as claimed in claim 1, comprising a lubricant discharge tube (130) being connected to the cylinder (122) at the bore end of the piston (120).

7. The system (100) as claimed in claim 6, comprising a second check valve (132) provided inside the lubricant discharge tube (130).

8. The system (100) as claimed in claim 6, comprising a second solenoid valve (150) configured to receive compressed air from the compressed air input device (102) and supply compressed air to the lubricant discharge tube (130).

9. The system (100) as claimed in claim 8, comprising an electronic control unit for electronically controlling the first solenoid valve (140) and the second solenoid valve (150).

Dated this 29th Day of September 2023

Hindalco Industries Limited
By their Agent

(Adheesh Nargolkar)
of Khaitan & Co
Reg No IN/PA-1086