Patent Application
20180010593
This disclosure relates generally to a pump for an air compressor, and more particularly to a belt driven oil-lubricated pump for an air compressor.
Air compressors are commonplace in home and commercial workshops. In general, an air compressor is a machine that decreases the volume and increases the pressure of a quantity of air by mechanical means. Air thus compressed possesses great potential energy, because when the external pressure is removed, the air expands rapidly. The controlled expansive force of compressed air is used in many ways and provides the motive force for air motors and tools, including pneumatic hammers, air drills, sandblasting machines, paint sprayers, and others.
A conventional air compressor includes a storage tank for compressed air, and a prime mover mounted on the compressor tank for compressing the air flowing into the compressor tank. The prime mover may be a gas engine or an electric motor, but many conventional models utilize electric power.
The basic components of an electric air compressor are an electric motor, a pump, a pressure switch, and a tank. The electric motor powers the pump which compresses the air and discharges it into the tank. For conventional air compressors, compressed air from the pump is discharged through a tube and a check valve into the tank. The check valve prevents air from flowing out of the tank back through the tube when the compressor pump is not in operation. Compressed air is stored in the tank.
The pump associated with such air compressors typically includes a crankcase and a crankshaft extending out of the crankcase. The crankshaft is driven by the electric motor. To seal the crankcase, a cover is mounted on the side of the crankcase through which the crankshaft extends. The cover typically supports the crankshaft and is made out of cast iron or other similar material.
Additionally, in pumps that are oil lubricated, the cover functions as a heat exchanger. More specifically, a fly wheel is usually disposed on the crankshaft and used to blow air onto an outer surface of the cover. Within the crankcase, some oil vapor in the hot pressurized air may contact with an inner surface of the cover and be condensed back into liquid oil. In order to allow hot air from within the cover to be vented, the cover typically includes a breather or other venting structure.
In use, as hot air leaves the crankcase, through the breather in the cover for example, some oil vapor is often vented to the atmosphere along with the hot air. This loss of oil vapor in the hot air vented to the atmosphere increases the oil consumption of the compressor pump as the pump continually loses oil in the vented hot air. Additionally, the oil vapor in the hot air that has been vented has a tendency to condense on the outside surface of the compressor pump, creating a dirty and undesirable appearance.
Thus, there is a need for developing a compressor pump which effectively and efficiently condenses oil vapor within the crankcase, lowering the amount of oil lost via the exiting hot air and, thereby decreasing the oil consumption of the compressor pump.
The present disclosure is directed to a compressor pump having a condensing chamber which allows oil vapor to be condensed and retained within the crankcase. An important feature of the present condensing chamber is that the condensing chamber is formed by a baffle shaped as an annular ring disposed between a crankcase and a crankcase cover. This configuration provides a seal between the crankcase and the crankcase cover. Additionally, the baffle provides improved alignment between the front and rear crankshaft bearings. Furthermore, this configuration allows for oil vapor to enter the condensing chamber and controls the flow of same. The baffle also facilitates the return of liquid oil to the crankcase after the oil has been condensed in the condensing chamber. In the preferred embodiment, the baffle is made of elastomeric material, but is also contemplated as being made of plastic or metal. Finally, it is thought that the baffle additionally functions as a thermal barrier between the hot crankcase interior and the cooler inner cavity of the condensing chamber. In other words, the present elastomeric baffle is constructed and arranged so that it insulates and forms a barrier between the condensing chamber which has cool air circulating across it, and the internal sump of the crankcase which has a mixture of hot oil, oil vapor and air.
Another important feature of the present compressor pump is that the cover for the crankcase includes ribs that protrude into the condensing chamber. It is believed to be particular advantageous if the ribs also extend outward from the outer surface of the cover. As described in greater detail below, such a configuration is believed to maximize cooling efficiency and condensation of the oil vapor back to a liquid.
Additional aspects, embodiments, and details of the present disclosure, all of which may be combinable in any manner, are set forth in the following detailed description of the disclosure.
One or more exemplary embodiments of the present disclosure will be described below in conjunction with the following drawing figures, in which:
With these general principles in mind, one or more embodiments of the present disclosure will be described with the understanding that the following detailed description is not intended to be limiting.
As shown in
The air compressor pump 10 is typically part of an air compressor that includes a tank (not shown), for example a 20-gallon cylindrical tank. Additionally, the air compressor includes a motor (not shown), typically an electric motor that can be powered via a typical AC wall outlet. However, other motors or power sources such as gasoline engines are contemplated. The particular sizes, shape, or configuration of the tank or motor is not believed to be important for the understanding of the present disclosure. Exemplary air compressors are described in, for example, U.S. Pat. No. 7,789,102 the entirety of which is incorporated herein by reference.
Returning to
Turning to
The baffle 32 includes a center opening 38 that is preferably sized to allow the front crankshaft bearing 34 and crankshaft seal 35 to pass therethrough. In the preferred embodiment, the diameter of the center opening 38 is dimensioned to maintain a sealing contact with a generally cylindrical, inwardly projecting formation 22a on the cover 22 (
With reference to
Preferably, the positioning aperture 40 and the condensing chamber aperture 42 are disposed on opposite sides along the circumference (i.e., 180 degrees apart along the circumference) of the baffle 32. For example, the positioning aperture 40 is preferably disposed proximate the top (relative to orientation in
The diameter of the positioning aperture 40 and the condensing chamber aperture 42 is contemplated as varying to suit the application. In certain exemplary embodiments, the positioning aperture 40 and the condensing chamber aperture 42 each have a diameter of 6.0 mm Preferably, the condensing chamber aperture 42 is sized to allow liquid to flow out of the condensing chamber 48 and into the crankcase 12 at the same time that hot air is flowing out of the crankcase 12 and into the condensing chamber 48.
Turning to
In operation, as the crankshaft 18 is rotated by a motor (not shown), pistons 52a, 52b will move in and out of the cylinder 14 compressing air, as is known, which can be discharged to and stored in the tank (not shown). The movement of the pistons 52a, 52b and/or the rotation of the crankshaft 18 will also generate heat within the crankcase 12. As operation continues, the heat will vaporize oil 54, creating oil vapor in the hot air within the crankcase 12. The hot air, with the oil vapor, passes through the condensing chamber aperture 42 and into the condensing chamber 48.
A fly wheel (not shown) is typically disposed on the crankshaft 18 proximate the cover 22 and will force relatively cool air towards the outer surface 26 of the cover 22. Within the condensing chamber 48, the hot air with the oil vapor contacts the inner surface 46 of the cover 22 and/or the ribs 50 (if present), causing heat to be absorb therefrom. The heat will be transferred to the ribs 28 on the outer surface 26 of the cover 22 and may be absorbed by cool air from the flywheel, discussed above. Inside of the condensing chamber 48, after heat is removed from the oil vapor, the oil vapor condenses into liquid oil. The liquid oil in the condensing chamber 48 passes through the condensing chamber aperture 42 and into the crankcase 12. Hot air in the condensing chamber 48, which is lean in oil vapor, is preferably vented to the atmosphere from the condensing chamber 48 through the vent aperture 30.
In the preferred embodiment, the baffle 32 additionally functions as a thermal barrier between the hot crankcase interior and the cooler inner cavity of the condensing chamber 48. In other words, the present baffle is constructed and arranged so that it insulates and forms a barrier between the condensing chamber 48, which has cool air circulating across it, and the internal sump of the crankcase 12 which has a mixture of hot oil, oil vapor and air.
Compared to existing air compressors pumps, the hot air exiting an air compressor pump according to the embodiments of the present disclosure will have less oil vapor in the vented hot air. This will decrease the loss of oil for the air compressor and accordingly decrease the consumption of same. Also, the exterior surface of the air compressor pump will not accumulate oil as quickly. Furthermore, the use of the present condensing chamber allows for a simpler venting structure, i.e., an aperture or the like, as opposed to breather or other such device typically used in conventional devices. The aperture also allows for the crankcase to vent even if the air compressor pump is not in operation, for example while the air compressor pump is being filled with oil. Additionally, the air compressor pump with the cover allows for easier construction and assembly of the air compressor pump.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the disclosure, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the disclosure.
The present application claims priority under 35 US 119 from U.S. Provisional application No. 62/358,973, filed Jul. 6, 2016.
| Number | Date | Country | |
|---|---|---|---|
| 62358973 | Jul 2016 | US |
