Vacuum Pump

This application is a continuation of co-pending U.S. patent application Ser. No. 18/131,083, filed on Apr. 5, 2023, now U.S. Pat. No. 12,385,489, which claims priority to U.S. Provisional Patent Application No. 63/476,240, filed on Dec. 20, 2022, and U.S. Provisional Patent Application No. 63/327,599, filed on Apr. 5, 2022, the entire contents of all of which are incorporated herein by reference.

The present invention relates to a pump, and more particularly to a vacuum pump.

Vacuum pumps may be used to remove or evacuate material such as unwanted air, gas, and non-condensables (e.g., water vapor), from an external system (e.g., an air conditioning system, a refrigeration system, etc.). Vacuum pumps may be used to evacuate the external system before the system is charged with refrigerant or when the existing system is undergoing repair (e.g., the refrigerant is already recovered). The vacuum pump may be connected to high- and low-pressure sides of the external system via hoses and a manifold. During operation, the vacuum pump creates a low-pressure zone that draws the unwanted materials such as air and non-condensables out of the external system, which has a high pressure, and into the vacuum pump.

The present disclosure provides, in one aspect, a vacuum pump that is connectable to an external system and configured to evacuate material from the external system, the vacuum pump including a main housing including a motor housing, a pump housing, and a partition wall that separates the motor housing and the pump housing, the pump housing is sealed relative to the motor housing to form a compression chamber that holds a lubrication fluid, a motor assembly that is positioned within the motor housing, a battery that is coupled to the motor housing and configured to supply electrical current to the motor assembly, and a pump assembly that is positioned within the compression chamber. The pump assembly is driven by the motor assembly and is in fluid communication with the compression chamber. The pump assembly includes a pump chamber, a rotor having vanes that is driven within the pump chamber, and a seal that is in sliding contact with the rotor. The seal is moveable relative to the rotor and is approximately tangentially engaged with an outer surface of the rotor. The seal includes a wall section having a radius equal to a radius of the pump chamber and the rotor includes a radius that is less than the radius of the pump chamber.

The present disclosure provides, in another aspect, a vacuum pump that is connectable to an external system and configured to evacuate material from the external system, the vacuum pump including a main housing including a motor housing, a pump housing, and a partition wall that separates the motor housing and the pump housing, the pump housing is sealed relative to the motor housing to form a compression chamber that holds a lubrication fluid, a motor assembly that is positioned within the motor housing, a battery that is coupled to the motor housing and configured to supply electrical current to the motor assembly, and a pump assembly that is positioned within the compression chamber. The pump assembly is driven by the motor assembly and is in fluid communication with the compression chamber. The pump assembly includes a pump chamber, a rotor having vanes that is driven within the pump chamber, and a seal that is in sliding contact with the rotor and includes a wall section. The seal is moveable relative to the rotor. The pump chamber includes a first fillet edge that is adjacent the seal and the wall section includes a second fillet edge that is adjacent the first fillet edge. The first and second fillet edges facilitate the vanes of the rotor to slide between the pump chamber and the seal without jamming.

Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

Before any embodiments of the present subject matter are explained in detail, it is to be understood that the present subject matter is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The present subject matter is capable of other embodiments and of being practiced or of being carried out in various ways.

illustrate a vacuum pumpincluding a housing, a handlecoupled to an upper portion of the housing, and a basecoupled to a lower portion of the housingto support the vacuum pumprelative to a support surface. The housingincludes () a trestle, a motor housingthat houses, protects, and/or conceals a motor assembly, an electronic control unit, and other electronic components. The housingfurther includes a pump housingthat houses a pump assemblywithin a compression chamber. The trestleis disposed between the motor housingand the pump housing.

With continued reference to, an inlet manifoldis positioned on an upper portion of the trestleand is in communication with the pump assemblyvia a valve switch(). The inlet manifoldis fluidly connected to a hosethat connects the vacuum pumpto an external system(e.g., an air conditioning system, a refrigeration system, etc.). In the illustrated embodiment, the inlet manifoldincludes multiple connection ports,,that are sized to connect to the hoseof the external system. For example, the connection ports,,may have various sizes (e.g., ½ inch, ⅜ inch, ¼ inch, etc.), as shown in. In the illustrated embodiment, the inlet manifoldis a flange-style tri-manifold that removes the need for thread locking and thread sealant. Instead, the inlet manifold() includes a flangewith an O-ring, providing a watertight connection between the inlet manifoldand the trestlewhich allows for ease of assembly and servicing of the compression chamber. Specifically, the O-ringis disposed on an outer periphery of the flangesuch that the inlet manifoldis in sealed fluid communication with the pump assembly. The flangeextends radially outward and is received under the trestleto inhibit removal of the inlet manifoldfrom the trestle. The inlet manifoldis fastened to the trestleusing a plurality of threaded fasteners() received within corresponding threaded boreswithin the trestle.

A battery packis removably coupled to an end portion of the housingvia a battery receptacle. The battery packprovides electrical current to the motor assemblythat drives the pump assemblyto remove or evacuate material such as air, gas, and non-condensables (e.g., water vapor) from the external system. The vacuum pumpincludes a control panelon one sidewall of the housingand a bumper() on an opposite sidewall of the housing. In the illustrated embodiment, the control panelis disposed on the motor housingand includes a power switchthat selectively activates the vacuum pumpand a Universal Serial Bus (USB) port. In some embodiments, an external display may be connected to the USB portto display information related to the operation of the vacuum pump(e.g., battery life remaining, micron gauge, etc.). In other embodiments, the control panelmay include a display (e.g., an LCD display). The bumperis composed of an elastomeric material (e.g., rubber) and is intended to protect the pumpfrom damage when inadvertently dropped or tipped from the upright orientation shown in. As shown in, the bumperis coupled to the trestleand includes a pair of T-ribsthat are received within a pair of corresponding slotsof the trestle. In other words, the T-ribsretain the bumperto the trestle. As shown in, the bumperalso includes a convex facefrom which the T-ribsproject. The convex facebends or deforms when laid flat (i.e., flush) against the housingas the T-ribsare received in the slots.

With reference to, the compression chamberis sealed relative to the motor housingvia the trestleso the compression chambercan hold lubrication fluid (e.g., oil). Specifically, the trestleincludes a partition wallthat seals the compression chamberfrom the motor housing. The trestledefines a fluid pathwaythat extends between the inlet manifoldand the pump assembly. The lubrication fluid positioned within the compression chamberis used to lubricate and cool the pump assemblyduring operation of the vacuum pump.

With reference to, the compression chamberfurther includes a fluid porthaving a removable cap, a fluid gaugepositioned on a sidewall of the pump housing, a release valvepositioned on the upper portion of the trestle, and a fluid drain valvepositioned at the bottom of the compression chamberadjacent the base. In the illustrated embodiment, a user may remove the removable capto fill the compression chamberwith lubrication fluid via the fluid port. The fluid portand the removable capmay also function as an exhaust during operation of the vacuum pump. The fluid gaugemay be transparent to allow a user to determine the amount of lubrication fluid that is held within the compression chamber. Also, the fluid drain valveallows the user to drain the lubrication fluid from the compression chamber.

With reference to, the motor assemblyis positioned within the motor housingand is coupled to the partition wallof the trestlevia a support bracket. The motor assemblyincludes a motorand a fandriven by the motor. In the illustrated embodiment, the motoris a brushless direct current (BLDC) motor that has a motor shafthaving a first end coupled to the fanand a second end coupled to the pump assembly, a rotorcoupled to the motor shaft, and a statorsurrounding the rotor. During operation of the motor, an electrical current flows through coils of the statorto produce a magnetic field around the rotor, causing the rotorand the motor shaftto rotate about a drive axisand drive the pump assembly. The fanis positioned between the electronic control unitand the motor assembly. The fanremoves heat from the electronic control unitand provides air to the motor assemblyto prevent overheating of each of the electronic control unitand the motor assembly. Although the motorof the illustrated embodiment is a BLDC motor, in other embodiments, the motormay alternatively be a brushed direct current motor or any other type of DC motor.

With reference to, the pump assemblyis a two-stage pump that has a first pump chamberand a second pump chamberin series with the first pump chamber. The first pump chamberhas a first pump inletin communication with the fluid pathwayand a first pump outletthat is in fluid communication with a second pump inletof the second pump chamber. The second pump chamberhas a second pump outletthat releases the pressure from the pump assemblyto the compression chamber. Although the illustrated pump assemblyis a two-stage pump (e.g., has first and second pump chambers), in other embodiments, the pump assemblymay only include a single stage or chamber.

With reference to, the first pump chamberincludes a first rotorand the second pump chambersincludes a second rotor. The first and second rotors,each include a pair of vanes,that are biased outward toward an interior surfaceof the pump chambers,() via centrifugal forces. In other embodiments, the vanes,may be biased outward via springs or some other biasing member. As a result, the rotation of the eccentrically mounted rotors,create low-pressure zones within the pump assembly, which draws material out of the external system() and into the pump assembly. The evacuated material is transferred from the first pump chamberto the second pump chamber, at which point the evacuated material is discharged into the compression chambervia the second pump outlet. In the illustrated embodiment, the second pump outletincludes a valve (e.g., a reed valve, etc.) that selectively releases the evacuated material into the compression chamberbefore being released from the vacuum pumpthrough the exhaust (e.g., via the cap) of the compression chamber.

With continued reference to, the first and second rotors,are eccentrically mounted within the first and second pump chambers,, respectively. Specifically, the first rotoris smaller in diameter relative to the first pump chamberand positioned such that an outer surfaceof the first rotoris approximately tangent to the interior surfaceof the first pump chamberadjacent the first pump inlet. Similarly, the second rotoris smaller in diameter relative to the second pump chamberand positioned such that an outer surfaceof the second rotoris approximately tangent to the interior surfaceof the second pump chamberadjacent the second pump inlet. As explained in further detail below, it is important for the first and second rotors,to be approximately tangent to the first and second pump chambers,to ensure a proper seal within the pump assembly.

To provide some background, if either of the rotors,are spaced too far away from the interior surfaceof the pump chambers,, then the pump assemblyfails to make a low-pressure zone because a proper seal cannot be made between the first pump inletand the second pump outlet. Now, if either of the rotors,are spaced too close to the interior surfaceof the pump chambers,, then excessive frictional forces are generated between the rotors,and the pump chambers,causing undue wear on the vacuum pump.

Returning to, the first pump chamberincludes a first sealthat is disposed between the first pump inletand the first pump outletfor creating a moveable seal with the first rotor. The first sealis in continuous engagement with the first rotorand moveable toward the first rotoralong a direction perpendicular to the drive axis. Also, the first sealis in sliding contact with the first rotorand the vanesas the first rotorrotates. A first springbiases the first sealtoward the first rotor. As illustrated, the first sealincludes a wall sectionthat has a radius equal to a radius R of the first pump chamber, while the first rotorincludes a radius r that is less than the radius R of the first pump chamber. That said, the wall sectionof the first sealremains approximately tangentially engaged with the outer surfaceof the first rotor.

Now, the second pump chamberalso includes a seal (i.e., a second seal) that is disposed between the second pump inletand the second pump outletfor creating a moveable seal with the second rotor. The second sealis in continuous engagement with the second rotorand moveable toward the second rotoralong a direction perpendicular to the drive axis. Also, the second sealis in sliding contact with the second rotorand the vanesas the second rotorrotates. A second springbiases the second sealtoward the second rotor. As illustrated, the second sealincludes a wall sectionthat has a radius equal to the radius R of the second pump chamber, while the second rotorincludes the radius r that is less than the radius R of the second pump chamber. That said, the wall sectionof the second sealremains approximately tangentially engaged with the outer surfaceof the second rotor. The spring stiffness of each spring,is configured to apply a sufficient force on the first and second seals,to create a proper seal within the first and second pump chambers,while avoiding excessive friction forces being generated that may otherwise damage the vacuum pump. Although the first and second seals,of the illustrated embodiments are composed of steel, in other embodiments, the first and second seals,may be composed of a variety of other types of material, such as plastics, ceramics, or flexible elastomers.

With reference to, the interior surfaceof the first and second pump chambers,include a fillet edgethat is adjacent another fillet edgeof the first and second seals,. The fillet edgeensures that the first and second seals,avoid catching a shoulderof the first and second rotors,adjacent the vanes,. The fillet edges,also reduce wear on the vanes,as the vanes,slide from the interior surfaceof the first and second pump chambers,to the wall sections,of the first and second seals,.

During operation, a user may attach the battery packto the battery receptacleof the vacuum pump, and fluidly connect the external systemto the vacuum pumpvia the inlet manifold(e.g., with the hose). The user may activate the vacuum pumpwith the control panel(e.g., by depressing the power switch) to activate the motor assemblyand begin evacuating material from the external system. When the vacuum pumpis activated, the first and second rotors,begin rotating within the first and second pump chambers,, which creates a low-pressure zone to evacuate material from the external system. As the first and second rotors,rotate, the first and second seals,are biased toward the first and second rotors,, respectively, and remain in continuous contact with the outer surface,of the first and second rotors,. Also, the first and second seals,remain in constant contact with the vanes,as the vanes,slide past the first and second seals,.

Various features of the invention are set forth in the following claims.