Abstract: A portable vacuum pump with a lubricating oil system having a quick oil change system. The oil change system includes at least two containers of oil and a switch mechanism operable to initially place the first container in fluid communication with the vacuum pump to serve as the primary oil reservoir while isolating the second container from such fluid communication. Then in a snap action, the switch mechanism can be flipped to place the second container with clean oil in fluid communication with the vacuum pump to serve as the primary oil reservoir and isolate the first container from fluid communication when its oil becomes dirty, all while the vacuum pump is still operating to evacuate an AC/R system. The first container can then be removed, refilled with clean oil, and returned in place and the switch mechanism flipped back to it when the second container of oil becomes dirty.

Abstract: A portable, refrigerant recovery unit for transferring refrigerant from a refrigeration system to a storage tank. The recovery unit includes two, opposed piston heads rigidly attached to respective piston rods that extend along a common fixed axis. The piston rods are rigidly attached to the yoke member of a scotch yoke arrangement. In operation, incoming refrigerant from the system is simultaneously and continuously directed to the opposing piston heads wherein the forces of the pressurized refrigerant on them counterbalance or neutralize one another. The recovery unit also has a cooling fan driven by the motor for driving the scotch yoke in which the fan is driven through a step up gearing arrangement. In operation, the drive shaft of the motor is rotated at a first rate and the driven shaft of the fan is driven at a greater rate (e.g., twice the first rate) by the step up gearing arrangement.

Abstract: A portable, refrigerant recovery unit to transfer refrigerant from a refrigerant system to a storage tank. The recovery unit includes a condenser bypass mode controlled by a valving arrangement that can be employed when the cooling and phase change functions of the condenser are not needed such as commonly exist during the initial stages of the overall recovery process when the refrigerant from the system may already be in liquid phase. In such cases, the bypass mode avoids having the flow run through the tubing and other plumbing of the condenser which otherwise would add significant length (e.g., 2-3 feet or more) and resistance to the flow through the recovery unit for a faster overall recovery process. The valving arrangement of the recovery unit has a single control knob and can be positioned in a plurality of modes including off, condenser bypass, recovery, and condenser purge.

Abstract: A portable, rotary vane vacuum pump with an automatic vacuum breaking arrangement that vents the pump to atmosphere whenever the drive motor ceases to rotate the pump. The arrangement prevents lubricating oil in any substantial amount from being undesirably drawn into the evacuated pump when the drive motor is shut off either intentionally or unintentionally. If the system being evacuated is also still connected to the pump, the arrangement will additionally vent it and greatly limit any amount of oil that may be undesirably sucked back into it. The pump further has a primary oil container that essentially holds all of the oil for the system. The primary container is preferably made of clear, rigid plastic and is also removable from the main body of the pump so it can be quickly and easily replaced with another container of fresh oil even while the pump is still operating.

Abstract: A portable, refrigerant recovery unit for transferring refrigerant from a refrigeration system to a storage tank. The recovery unit includes two, opposed piston heads rigidly attached to respective piston rods that extend along a common fixed axis. The piston rods are rigidly attached to the yoke member of a scotch yoke arrangement. In operation, incoming refrigerant from the system is simultaneously and continuously directed to the opposing piston heads wherein the forces of the pressurized refrigerant on them counterbalance or neutralize one another. The recovery unit also has a cooling fan driven by the motor for driving the scotch yoke in which the fan is driven through a step up gearing arrangement. In operation, the drive shaft of the motor is rotated at a first rate and the driven shaft of the fan is driven at a greater rate (e.g., twice the first rate) by the step up gearing arrangement.

Abstract: A portable, refrigerant recovery unit for transferring refrigerant from a refrigeration system to a storage tank. The recovery unit includes two, opposed piston heads rigidly attached to respective piston rods that extend along a common fixed axis. The piston rods are rigidly attached to the yoke member of a scotch yoke arrangement. In operation, incoming refrigerant from the system is simultaneously and continuously directed to the opposing piston heads wherein the forces of the pressurized refrigerant on them counterbalance or neutralize one another. The scotch yoke arrangement includes a two-piece slide mechanism mounted about a cylindrical crank pin and a single piston embodiment is additionally disclosed.

Abstract: A combined debris catcher and pressure relief valve positionable between first and second ports of an inlet arrangement that is upstream of the main body of a vacuum pump. The debris catcher includes an open ended tube that is spring biased upwardly and in normal operation forms a seal with the inlet arrangement. In the raised or sealed position, incoming fluid from the system to be evacuated travels along a closed flow path through the first port of the inlet arrangement, through the debris catcher, and out through the second port of the inlet arrangement into the main body of the vacuum pump. If the inlet arrangement is hooked up initially or at any time to a system that is above atmospheric pressure, the above atmospheric pressure will overcome the upward force of the spring on the tube and cause the tube to move to an open position spaced from the inlet arrangement harmlessly venting the high pressure fluid to ambient air and avoiding potential damage or contamination to the pump.

Abstract: A portable, refrigerant recovery unit for transferring refrigerant from a refrigeration system to a storage tank. The unit includes two, opposed piston heads rigidly attached to respective piston rods that extend along a common fixed axis and are rigidly attached to a scotch yoke arrangement. In operation, incoming refrigerant is simultaneously and continuously directed to the opposing piston heads wherein the forces of the pressurized refrigerant on them counterbalance one another. The flow path of the refrigerant is designed to be isolated from the piston rods and drive mechanism to avoid any exposure to any contaminants in the refrigerant. However, to the extent the undersides of the piston heads and portions of the piston rods may be so exposed, a chamber is provided adjacent each piston underside to capture or collect any contaminants and direct them harmlessly back through one-way exhaust lines into the incoming refrigerant lines.

Abstract: A portable, refrigerant recovery unit for transferring refrigerant from a refrigeration system to a storage tank. The recovery unit includes two, opposed piston heads rigidly attached to respective piston rods that extend along a common fixed axis. The piston rods are rigidly attached to the yoke member of a scotch yoke arrangement. In operation, incoming refrigerant from the system is simultaneously and continuously directed to the opposing piston heads wherein the forces of the pressurized refrigerant on them counterbalance or neutralize one another. The scotch yoke arrangement includes a two-piece slide mechanism mounted about a cylindrical crank pin and a single piston embodiment is additionally disclosed.

Abstract: A portable, refrigerant recovery unit for transferring refrigerant from a refrigeration system to a storage tank. The recovery unit includes two, opposed piston heads rigidly attached to respective piston rods that extend along a common fixed axis. The piston rods are rigidly attached to the yoke member of a scotch yoke arrangement. In operation, incoming refrigerant from the system is simultaneously and continuously directed to the opposing piston heads wherein the forces of the pressurized refrigerant on them counterbalance or neutralize one another. The scotch yoke arrangement includes a two-piece slide mechanism mounted about a cylindrical crank pin and a single piston embodiment is additionally disclosed.

Abstract: A portable, rotary vane vacuum pump with an automatic vacuum breaking arrangement that vents the pump to atmosphere whenever the drive motor ceases to rotate the pump. The arrangement prevents lubricating oil in any substantial amount from being undesirably drawn or sucked into the evacuated pump when the drive motor is shut off either intentionally or unintentionally. If the system being evacuated is also still connected to the pump, the arrangement will additionally vent it and greatly limit any amount of oil that may be undesirably sucked back into it. The pump also has a primary oil container that essentially holds all of the oil for the system. The primary container is preferably made of clear, rigid plastic so that the condition of the oil in the system can be visually monitored. It is also removable from the main body of the pump and can be quickly and easily replaced with another container of fresh oil even while the pump is still operating.

Abstract: A combined debris catcher and pressure relief valve positionable between first and second ports of an inlet arrangement that is upstream of the main body of a vacuum pump. The debris catcher includes an open ended tube that is spring biased upwardly and in normal operation forms a seal with the inlet arrangement. In the raised or sealed position, incoming fluid from the system to be evacuated travels along a closed flow path through the first port of the inlet arrangement, through the debris catcher, and out through the second port of the inlet arrangement into the main body of the vacuum pump. If the inlet arrangement is hooked up initially or at any time to a system that is above atmospheric pressure, the above atmospheric pressure will overcome the upward force of the spring on the tube and cause the tube to move to an open position spaced from the inlet arrangement harmlessly venting the high pressure fluid to ambient air and avoiding potential damage or contamination to the pump.