Field of the Invention The invention relates' to the technical field of vacuum equipment, in particular to a mechanical pump oil return valve device or arrangement which can be applied to a mechanical pump such as a rotary vane pump.
Background
ORV" (Oil Return Valve) is a unique innovative design made in pumps to enhance its ultimate vacuum. In this range of equivalent pumps there is a continuous external leak made, specifically for recirculation of oil separated by Exhaust Mist Filter (EMF) back into oil tank through pump cartridge. This type of continues leaks are provided directly into Gas ballast (GB) line or directly into cartridge induction zone which effects the pump ultimate vacuum.
In the existing vacuum pumps, there is a compromise in vacuum during recirculation of separated oil from Exhaust Mist Filter (EMF) back to oil tank. A separated oil line is connected either to Gas ballast (GB) line or directly to pump suction line, whereas in both circuits there is a continuous air leak when there is no oil separation from EMF which effects ultimate vacuum of pump.

In some other higher sizes of pumps series, a float operated valve is used for recirculating EMF separated oil which works on buoyancy force, but in the small pumps it's difficult to accommodate the float valve due to space constrains and manufacturing difficulty to make a small float valve which also increases cost of manufacturing since parts has to be accurate for sealing.
Objective To achieve better vacuum and to avoiding two model variants like some other manufactures have based on inlet pressures requirement which is fundamentally effected by EMF separated oil circulation.
Summary of the Invention In accordance with the invention provides an Oil Return Valve (ORVj assembly in a vacuum pump. In an embodiment, the oil return valve (ORV) which is disposed externally with the pump oil tank of the vacuum pump. The valve includes a drive frame having a first end, a second end and an intermediate body connecting the first end and the second end. The first end of the drive frame is hinged at the upper part of the pump oil tank and the second end of the drive frame ">rw""1 "^^c => i-w-»rM-*ot* sealing the hole cavity of the oil returning base. The

intermediate body having a spring support with a stopper, a flexible gas impervious diaphragm disposed outside the pump oil tank and attached externally to the drive frame. In an operation, the valve operates by using back pressure which is generated in the pump oil tank, the back pressure in the tank actuates the diaphragm from inside and thereby further lifting the liver to open the poppet sealed hole which is connected to the vacuum line.
Brief Description of the drawings The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which: Figure 1 shows schematic view of oil tank with Oil Return Valve (ORV) according to one embodiment of the present invention.
Figure 2 shows operating condition of Oil Return Valve, according to one embodiment of the present invention.
Figure 3 shows Oil Return Valve of figure 2 under close operating condition, according to one embodiment of the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
Detailed description of the drawings By introducing Oil return Valve (ORV) in pumps, ultimate vacuum pressure will be improved and Gas ballast valve can be kept closed or open in all operating pressures without effecting recirculation of EMF separated oil back to tank. The Oil Return Vale (ORV) which operates using back pressure built in oil tank by Exhaust mist filter (EMF).
Figure 1 (a) & 1 (b) shows sectional view of the oil tank with Oil Return Valve (ORV) assembly, according to one embodiment of the present invention. The Oil Return Valve (ORV) assembly (100) including an oil returning base (190) which is disposed on the base of a pump oil "tank '"'('1201) of fcne vacuum "pump. "The "oil "returning base

(190) is provided with a venting hole (135) with a cavity (139), the cavity (139) is formed between the oil return base (190) and pump cartridge (195). In an example embodiment, the oil return valve (ORV) (110) is disposed externally with the pump oil tank (120) of the vacuum pump. The valve includes a drive frame (130). The drive frame having a first end (132), a second end (134) and an intermediate body (136) connecting the first end (132) and the second end (134) . In an example embodiment, the drive frame (130) may be tapered at one end in comparison with the other end. The first end (132) of the drive frame (130) is hinged (131) at the upper part of the pump oil tank (120) and the second end (134) of the drive frame (130) includes a poppet (133) sealing the hole cavity (135) of the oil returning base. The intermediate body (136) having a spring support (137) with a stopper, a flexible gas impervious diaphragm (138) disposed outside the pump oil tank (120) and attached externally to the drive frame (130) .
In an example embodiment, during operation, the valve operates by using back pressure which is generated in the pump oil tank (120). The back pressure in the tank is generated by resistance from Exhaust Mist Filter (EMF) which is used to separate oil from exhaust gases carrying out oil m roirm of mist.1 The- oacx-pressure in

the tank actuates the diaphragm (138) from inside and thereby further lifting the liver to open the poppet sealed hole which is connected to the vacuum line. Further, the separated oil get sucked back in the cartridge induction zone and further oil is transferred back to oil reservoir from cartridge exhaust valve. The ultimate vacuum pressure will be improved and a Gas ballast valve can be kept closed or open in all operating pressures without effecting recirculation of EMF separated oil back to tank.
Operating principle of ORV (shown in figure 2 & figure 3) :
The valve operates by using back pressure in oil tank, the back pressure in tank is generated by resistance from Exhaust Mist Filter (EMF) which is used to separate oil from exhaust gases carrying out oil in form of mist. The back pressure in tank actuates the diaphragm and further lifts the liver to open the poppet sealed hole which is connected to vacuum line. Further the separated oil get sucked back in the cartridge induction zone and further oil is transferred back to oil reservoir from cartridge exhaust valve. Benefits: IT) G-reatesX fcu,],timate vacuum

2) Single variant for complete range of vacuum from its ultimate to near atmospheric pressure
3) GB valve can be kept closed or open in all operating pressures without effecting recirculation of EMF separated oil back to tank.
Applications of invention
The pump is used in vast application like, food packing machines, Gold casting of ornaments, pick and place, Vacuum holding etc.
While the invention has been described in connection with a series of examples, principles and/or embodiments, these descriptions are not intended to limit the scope of the invention to the particular forms set forth herein. The above description is illustrative and not restrictive. Many variations of the invention will become apparent to those of skill in the art upon review of this disclosure. The scope of the invention should, therefore, be determined not with reference to the above description.
The present descriptions are intended to cover such alternatives, modifications, and equivalents as may be included within the scope of the invention. In several respects, embodiments of the present invention may act t^o close the loopholes in the current industry practices

in which good business practices and logic are lacking because it is not feasible to implement with current resources and tools.
We Claim:
1. An Oil Return Valve (ORV) assembly (100) in a vacuum pump, comprising:
an oil returning base (190) is disposed on the base of a pump oil tank (120) of the vacuum pump, wherein the oil returning base (190) is provided with a venting hole (135) with a cavity (139), the cavity (139) is formed between the oil return base (190) and a pump cartridge (195); and
an oil return valve (ORV) (110) disposed externally
with the pump oil tank (120) of the vacuum pump, the
valve includes' a drive frame (130) having a first end
(132), a second end (134)and an intermediate body (136)
'connecting the? < fitst end (i3'2)'' 'arid'" the sfedbhd* 2nd (134),

the first end (132) of the drive frame (130) is hinged (131) at the upper part of the pump oil tank (120) and the second end (134) of the drive frame (130) includes a poppet 133) sealing the hole cavity (135) of the oil returning base, and the intermediate body (136) having a spring support (137) with a stopper, a flexible gas impervious diaphragm (138) disposed outside the pump oil tank (120) and attached externally to the drive frame (130),
wherein, during operation, the valve operates by using back pressure which is generated in the pump oil tank (120), the back pressure in the tank actuates the diaphragm (138) from inside and thereby further lifting the liver to open the poppet sealed hole which is connected to the vacuum line.
2. The ORV assembly as claimed in claim 1, wherein the back pressure in the tank is generated by resistance from Exhaust Mist Filter (EMF) which is used to separate oil from exhaust gases carrying out oil in form of mist.
3. The ORV assembly as claimed in claim 1, wherein the separated oil get sucked back in the cartridge induction zone and further oil is transferred back to oil reservoir from cartridge exhaust valve.

4. The ORV assembly as claimed in claim 1, wherein ultimate vacuum pressure will be improved and a Gas ballast valve can be kept closed or open in all operating pressures without effecting recirculation of EMF separated oil back to tank.
5. The ORV assembly as claimed in claim 1 operates using back pressure built in oil tank by Exhaust mist filter (EMF) .
6. The ORV assembly as claimed in claim 1 used in application including food packing machines, Gold casting of ornaments, pick and place, Vacuum holding etc.