Vacuum pump oil distribution system with integral oil pump

An improved vacuum pump comprising a housing, and a pair of cylinders within said housing, each cylinder having a gas intake port and a gas exhaust port, a pair of rotating pistons, one of said pistons being arranged within each said cylinder, an oil reservoir containing lubricating oil, and means for maintaining said oil reservoir at a partial vacuum, the partial vacuum allowing for the separation of volatile contaminants from the oil by evaporation, wherein the improvement to the vacuum pump comprises:

• an elongated shaft arranged within the housing for driving the pistons, the pistons being eccentrically mounted on said shaft, said shaft having a passage extending axially from one end;
• a plurality of bearings arranged at spaced locations lengthwise of said shaft for rotatably mounting said shaft;
• a plurality of oil ports arranged in said shaft, said oil ports communicating between said passage and the outer surface of said shaft, at least one of said oil ports being arranged adjacent to each of said bearings;
• and
• an oil pump for supplying oil to said bearings, and further comprising means for drawing the oil from the reservoir against the partial vacuum, said oil pump being mounted adjacent to said one end of said shaft, said oil pump having an oil inlet communicating with the oil reservoir and an oil outlet communicating with said passage for pumping the oil from the reservoir into said passage, the oil pumped therein exiting said passage through said oil ports and thereby lubricating said bearings, the oil being further pumped from the cylinder by the pistons through the gas exhaust port and returned to the reservoir.

A method of lubricating bearings of a vacuum pump, comprising the steps of:

• providing a reservoir for lubricating oil;
• providing a shaft;
• providing at least one bearing mounted within said vacuum pump for supporting said shaft in rotational motion;
• providing piston means operatively engaging said shaft for pumping a gas;
• providing an axial passage extending from one end of said shaft at least to a point adjacent to said bearing, said passage remaining at atmospheric pressure for a predetermined duration of operation of said vacuum pump;
• providing a port adjacent to said bearing and communicating between said passage and said bearing;
• providing an oil pump mounted adjacent to said one end of said shaft;
• pumping lubricating oil during and after said predetermined duration of operation from said reservoir into said passage and out of said port by driving said pump with said shaft;
• and
• directing said lubricating oil from said port onto said bearing.

A vacuum pump, comprising:

• a pump casing having a cylindrical interior surface and first and second end walls arranged at each end of said cylindrical interior surface, said casing and said end walls defining a cylindrical chamber, each said end wall having an aperture therethrough coaxially aligned with said cylindrical chamber, said pump casing having a gas intake port and a gas exhaust port;
• an elongated shaft extending coaxially within said pump casing and having first and second ends extending through said first and second end wall apertures respectively;
• a bearing mounted within said first end wall aperture, said shaft being rotatably mounted thereon;
• a metering ring mounted on said shaft within said first end wall aperture between said bearing and said cylindrical chamber, said metering ring having a circumferential edge extending radially outwardly and constricting said first end wall aperture;
• a piston eccentrically mounted on said shaft for motion within said cylindrical chamber, said piston having an exterior surface contacting said cylindrical interior surface and forming an orbiting seal during said motion for drawing gas into said cylindrical chamber through said intake port and expelling the gas through said exhaust port;
• a passage extending axially through said shaft from said first to said second end;
• an oil port extending from said passage to the outer surface of said shaft at a position along said shaft proximal to said first end and externally to said first end wall, said oil port being in fluid communication with said bearing;
• an oil pump mounted externally to said cylindrical chamber on said second end wall, a drive connection from the second end of said shaft for driving said oil pump upon shaft rotation, said oil pump having an oil outlet and an oil inlet, said outlet communicating with said passage at said second end of said shaft;
• an oil reservoir;
• a first oil conduit connecting said oil reservoir to said oil inlet;
• a means for separating oil from gas connected to said gas exhaust port externally of said cylindrical chamber;
• and
• a second oil conduit connecting said oil separating means with said reservoir, the oil being pumped from said reservoir through said passage out of said oil port and then flowing to and thereby lubricating said bearing, said oil further flowing through said first end wall aperture into said cylindrical chamber thereby lubricating said piston and providing said orbiting seal between said piston exterior surface and said cylindrical interior surface, said metering ring controlling the rate of oil flow through said first end wall aperture into said cylindrical chamber, said oil being thereafter expelled from said cylindrical chamber through said gas exhaust port into said oil separating means and returned to said reservoir through said second oil conduit.

A vacuum pump, comprising:

• a pump casing defining a cylindrical interior surface;
• first and second end walls arranged at each end of said cylindrical interior surface and a common-wall arranged between said first and second end walls within said casing, said end walls and said common wall defining first and second cylindrical chambers arranged coaxially end to end, each of said walls having a respective aperture therethrough coaxially aligned with said cylindrical chambers, said first cylindrical chamber having a gas intake port and a gas exhaust port;
• an elongated shaft having first and second ends, said shaft extending coaxially within said cylindrical chambers through said common wall aperture, said first and second ends extending through said first and second end wall apertures respectively;
• a bearing mounted within said first end wall aperture, said shaft being rotatably mounted thereon;
• a metering ring mounted on said shaft within said first end wall aperture between said bearing and said first cylindrical chamber, said metering ring having a circumferential edge extending radially outwardly and constricting said first end wall aperture;
• a piston eccentrically mounted on said shaft for motion within said first cylindrical chamber, said piston having an exterior surface contacting said cylindrical interior surface and forming an orbiting seal during said motion for drawing gas into said first cylindrical chamber through said intake port and expelling the gas through said exhaust port;
• a passage extending axially through said shaft from said first to said second end;
• an oil port extending from said passage to the outer surface of said shaft at a position along said shaft proximate to said first end and externally of said first end wall, said oil port being in fluid communication with said bearing;
• an oil pump mounted on said second end wall externally to said second cylindrical chamber, a drive connection from the second end of said shaft for driving said oil pump upon shaft rotation, said oil pump having an oil outlet and an oil inlet, said outlet communicating with said passage at said second end of said shaft;
• an oil reservoir;
• a first oil conduit connecting said oil reservoir to said oil inlet;
• a means for separating oil from gas connected to said gas exhaust port and disposed externally of said cylindrical chambers;
• and
• a second oil conduit connecting said oil separating means with said reservoir, the oil being pumped from said reservoir through said passage out of said oil port and then flowing to and thereby lubricating said bearing, said oil further flowing through said first end wall aperture into said first cylindrical chamber thereby lubricating said piston and providing said orbiting seal between said piston exterior surface and said cylindrical interior surface, said metering controlling the rate of oil flow through said first end wall aperture into said first cylindrical chamber, said oil being thereafter expelled from said first cylindrical chamber through said respective gas exhaust port into said oil separating means and returned to said reservoir through said second oil conduit.

An improved vacuum pump comprising a housing, and a pair of cylinders within said housing, each cylinder having a gas intake port and a gas exhaust port, a pair of rotating pistons, one of said pistons being arranged within each said cylinder, and an oil reservoir containing lubricating oil, wherein the improvement to the vacuum pump comprises:

• an elongated shaft arranged within the housing for driving the pistons, the pistons being eccentrically mounted on said shaft, said shaft having a passage extending axially from one end, said passage remaining substantially at atmospheric pressure for a predetermined duration of operation of said vacuum pump;
• a plurality of bearings arranged at spaced locations lengthwise of said shaft for rotatably mounting said shaft;
• a plurality of oil ports arranged in said shaft, said oil ports communicating between said passage and the outer surface of said shaft, at least one of said oil ports being arranged adjacent to each of said bearings;
• an oil pump for supplying oil to said bearings, said oil pump comprising means for pumping the oil into said passage during said predetermined period of operation, said oil pump being mounted adjacent to said one end of said shaft, said oil pump having an oil inlet communicating with the oil reservoir and an oil outlet communicating with said passage for pumping the oil from the reservoir into said passage, the oil pumped therein exiting said passage through said oil ports and thereby lubricating said bearings, the oil being further pumped from the cylinder by the pistons through the gas exhaust port and returned to the reservoir.

A method of lubricating bearings of a vacuum pump, comprising the steps of:

• providing a reservoir for lubricating oil;
• providing a shaft;
• providing at least one bearing mounted within said vacuum pump for supporting said shaft in rotational motion;
• providing piston means operatively engaging said shaft for pumping a gas;
• providing an axial passage extending from one end of said shaft at least to a point adjacent to said bearing;
• providing a port adjacent to said bearing and communicating between said passage and said bearing;
• providing an oil pump mounted adjacent to said one end of said shaft;
• maintaining said reservoir at a partial vacuum to allow volatile contaminants to evaporate from the lubricating oil therein;
• pumping lubricating oil from said reservoir against said partial vacuum into said passage and out of said port by driving said pump with said shaft;
• and
• directing said lubricating oil from said port onto said bearing.