Reciprocating compressor crankshaft adapter and method

Method and device for lubricating a connection. A housing is configured to house a crankshaft adapter that connects an oil pump to a compressor. The housing includes a shell forming a round cavity configured to receive the crankshaft adapter; an oil feed conduit configured to enter through the shell into the round cavity and to deliver oil; a first drain conduit, opposite to the oil feed conduit, and configured to enter through the shell into the round cavity; a plug provided in the first drain conduit; and a second drain conduit configured to enter through the shell into the round cavity. The second drain conduit is located between the oil feed conduit and the first drain conduit, substantially between 50 and 130 degrees relative to the first drain conduit on a periphery of the shell.

BACKGROUND

Technical Field

Embodiments of the subject matter disclosed herein generally relate to methods and systems and, more particularly, to mechanisms and techniques for distributing oil on a connection.

Discussion of the Background

Gas transmission pipelines, petrochemical plants, refineries and many other industries all depend on a reciprocating compressor. Due to many factors, including but not limited to the quality of the initial specification/design, adequacy of maintenance practices and operational factors, industrial facilities can expect widely varying life cycle costs and reliability from their own installations. One such factor that affects the life cycle of the reciprocating compressor is the oil pump and its connection to the compressor's crankshaft.

FIG. 1(which corresponds to FIG. 1 of U.S. Patent Application Publication US 2008/0169157 A1, the entire content of which is incorporated herein by reference) shows a compressor10including a casing12. Working pistons14are mounted for reciprocating movement within cylinders16. Each piston is connected to a crankshaft18via a connecting rod20. Connecting rod20is secured around offset portion22of crankshaft18. Crankshaft18includes counterbalance24for balancing the rotational irregularities in the crankshaft. The crankshaft extends through shaft seal cavity26of housing12. End28of the crankshaft18may be connected to an oil pump (not shown). The oil pump is configured to pump oil to various bearings of the compressor. The oil pump is activated by the rotation of the crankshaft18. An interface between the crankshaft18and a shaft of the oil pump may include a connection adapter. The connection adapter is configured to indirectly receive part of the oil pumped by the oil pump and to lubricate the connection between the oil pump and the compressor.

However, the existing connection adapter is not capable of fully spreading the oil around the connection between the oil pump and the compressor for which reason this method of lubrication is not sufficient and the connection may fail prematurely, thus bringing the entire compressor to a standstill. This outcome is undesirable for the operator of the compressor as the entire processing cycle has to be stopped for fixing the compressor. Alternatively, the compressor itself may fail if the failure of the connection is not observed in time as oil will stop being pumped to the bearings, which will result in a large increase in the temperature of the compressor and subsequent failure.

Accordingly, it would be desirable to provide systems and methods that improve the capabilities of the above discussed systems.

SUMMARY

According to one exemplary embodiment, there is a housing configured to house a crankshaft adapter that connects an oil pump to a compressor. The housing includes a shell forming a round cavity configured to receive the crankshaft adapter; an oil feed conduit configured to enter through the shell into the round cavity and to deliver oil; a first drain conduit, opposite to the oil feed conduit, and configured to enter through the shell into the round cavity and to drain the oil from the round cavity; a plug provided in the first drain conduit to reduce an amount of oil drained away from the round cavity; and a second drain conduit configured to enter through the shell into the round cavity and to drain away oil from the round cavity. The second drain conduit is located between the oil feed conduit and the first drain conduit, substantially between 50 and 130 degrees relative to the first drain conduit.

According to another exemplary embodiment, there is a reciprocating compressor that includes a casing; an oil pump attached to the casing and configured to pump oil through the compressor; a crankshaft adapter that connects the oil pump to the compressor and the crankshaft adapter has at least one fin on an outer periphery; and a housing interposed between the casing and the oil pump and configured to house the crankshaft adapter. The housing includes a shell forming a round cavity configured to receive the crankshaft adapter, an oil feed conduit configured to enter through the shell into the round cavity and to deliver oil, a first drain conduit, opposite to the oil feed conduit, and configured to enter through the shell into the round cavity and to drain the oil from the round cavity, a plug provided in the first drain conduit to reduce an amount of oil drained away from the round cavity, and a second drain conduit configured to enter through the shell into the round cavity and to drain away oil from the round cavity. The second drain conduit is located between the oil feed conduit and the first drain conduit, substantially between 50 and 130 degrees relative to the first drain conduit.

According to still another exemplary embodiment, there is a method for oiling an inside of a housing provided between an oil pump and a compressor. The method includes attaching the housing between the oil pump and the compressor; placing a crankshaft adapter inside a shell of the housing, the shell having a round cavity and the crankshaft adapter having at least one fin on an outer periphery of the crankshaft adapter; establishing an oil feed conduit through the shell to penetrate into the round cavity for delivering oil; forming a first drain conduit, opposite to the oil feed conduit, to enter through the shell into the round cavity and to drain the oil from the round cavity; placing a plug in the first drain conduit to reduce an amount of oil drained away from the round cavity; and establishing a second drain conduit through the shell into the round cavity to drain away oil from the round cavity. The second drain conduit is located between the oil feed conduit and the first drain conduit, substantially between 50 and 130 degrees relative to the first drain conduit.

DETAILED DESCRIPTION

The following description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. The following embodiments are discussed, for simplicity, with regard to the terminology and structure of a reciprocating compressor having an oil pump. However, the embodiments to be discussed next are not limited to these systems, but may be applied to other systems that involve a connection between two rotating elements that needs to be oiled or cooled.

According to an exemplary embodiment, a crankshaft adapter in a compressor is placed in a housing that is configured to receive oil and the crankshaft adapter lubricates an interface between an oil pump and the compressor. The amount of oil leaving the housing is controlled through a cap placed in a drain conduit and also through a drain hole located at a predetermined position in the housing. The crankshaft adapter may have fins for improving the lubrication.

According to an exemplary embodiment,FIG. 2shows a reciprocating compressor30having an oil pump32. The oil pump32is attached to a case34of the compressor30by, for example, bolts36. The oil pump32has a shaft38that is attached to an impeller40for pumping oil42from a chamber44inside the oil pump32to various locations (bearings, crankshaft adapter, etc.) in the compressor30. Shaft38has an end46that is attached to a crankshaft adapter48.

An overview of the crankshaft adapter48is shown inFIG. 3. According to this exemplary embodiment, the crankshaft adapter48has a splined portion50that is configured to attach to a corresponding splined portion52of the shaft38. The splined connection may be secured with an appropriate pin54(seeFIG. 2) that is accommodated by a hole56(seeFIG. 3) in the crankshaft adapter48. Other connections between the crankshaft adapter and the shaft of the of the oil pump may be uses, e.g., helical connection, key connection, etc. Crankshaft adapter48may have a first set of one or more holes58for allowing the oil to pass the adapter and a second set of one or more holes60. The second set of holes60may be used to bolt the crankshaft adapter48to a crankshaft62of the compressor30. In this regard,FIG. 2shows bolts64being inserted through holes60of the crankshaft adapter48and fixed into the crankshaft62. The crankshaft adapter48may have one or more fins (paddles)61on an outer periphery for better oil lubrication of the connection.FIG. 3shows four fins61. However, the number of fins may be between 1 and 10.

By having the arrangement illustrated inFIG. 2, a rotation of the crankshaft62of the compressor30determines a rotation of the shaft38of the oil pump32, and thus, the activation of the oil flow through various conduits. For example,FIG. 2shows an output port66and an input port68through which the oil is passed back and forth to the compressor. Conduits70transport the oil between the oil pump32and the compressor30.

A housing80is attached (e.g., bolted) to the casing34of the compressor30and to the oil pump32as shown inFIG. 2. The housing80is configured to house the crankshaft adapter48, the splined end46of the shaft38and an end of the crankshaft62of the compressor30. In one application, the housing80can house only one or two of the above noted elements.

FIG. 4shows in more details the housing80and some of the elements inside the housing and in the vicinity of the housing. This figure shows an oil feed conduit82that receives oil from the oil pump32(e.g., from output port66) and provides the oil to a bearing84. Part of the received oil flows in a chamber86formed inside the housing80. In one application, the crankshaft adapter48is completely provided inside the chamber86of the housing80.

A drain conduit88formed in the housing80has a predetermined internal diameter. However, this predetermined internal diameter (which is dictated by a combination of factors, e.g., manufacturer, capacity of oil pump, type of oil, etc.) is too large for maintaining a desired amount of oil inside chamber86. Not having enough oil in chamber86, the lubrication performed by the crankshaft adapter48is diminished, which may result in an early failure of the splined connection. A plug90may be provided inside the drain conduit88for limiting the amount of oil that drains from chamber86. In this way, an amount of oil present in the chamber86is increased. However, there are times when the compressor is not in use and thus, it is desirable to allow the oil in chamber86to drain away. Thus, in one exemplary embodiment, the plug90may have a weep hole (channel)92that allows the oil to drain when the compressor is not in use. It is noted that the weep hole92is optional and the inside diameter of the weep hole depends on the size of the chamber86, the type of oil, the manufacturer, etc.

According to an exemplary embodiment,FIG. 5is an overview of housing80having the plug90provided in the drain conduit88. It is noted in this figure a shell91made of metal and configured to define part of the chamber86.

According to another exemplary embodiment shown inFIG. 6, housing80has an additional drain hole (or conduit)96disposed on a side of the housing, at a predetermined height relative to the first drain conduit88. The predetermined height is better illustrated by consideringFIG. 7, which shows a top view of the housing80(from the oil pump).FIG. 7shows that the second drain hole96is provided substantially at 90 degrees relative to the first drain conduit88. However, in another exemplary embodiment, the second drain hole96is provided between 50 degrees and 130 degrees relative to the first drain conduit88, as illustrated by lines98and100. The second drain hole96is such dimensioned that any oil that overflows from chamber86is handled in a timely manner (e.g., drained out of the chamber86).

Still with regard toFIG. 6, it is noted that the location of the second drain hole96to the first drain conduit is about 9 o'clock when viewing the housing80along axis X. However, this position is dependent on the rotational direction of the crankshaft adapter48. InFIG. 6it is assumed that the crankshaft adapter48rotates as indicated by arrow R. However, if the rotational motion of the crankshaft adapter48is reversed, then the location of the second drain hole96is moved to be around 3 o'clock (between 2 and 4 o'clock). One reason for this correlation is to not force the oil too quickly out of the chamber86through the second drain hole96when the crankshaft adapter48rotates.

The actual dimension of the drain hole96depends from compressor to compressor but is noted that the drain hole96should handle a rotation of the crankshaft of, for example, 1800 rpm, and a pressure of the oil of around 50 psi.FIG. 7also shows various holes102formed in a flange region of the housing80and these holes accommodate bolts that bolt the housing80to the compressor30. Further, the housing80has additional holes104(also shown inFIG. 6) for attaching the housing to the oil pump32.

Because of the reduced drainage through drain conduit88, the overflow drainage provided by hole96, and the fins of the crankshaft adapter, a better oil distribution in the housing86, around the crankshaft adapter48, is obtained. A test performed on a reciprocating compressor having a splined oil pump and a crankshaft adapter as shown inFIGS. 2-7indicates that oil42is splashed almost uniformly as shown inFIG. 8. On the contrary, when the same test is performed on the same compressor but without plug90, second drain hole96, and fins61as shown inFIG. 9, the test indicates that the oil42is being splashed only at a bottom portion of the crankshaft adapter48as shown inFIG. 10. Crankshaft adapter48may have four fins110as shown inFIG. 8for more efficiently splashing the oil42.

The oil being drained from the second drain hole96follows a path that intersects the first-drain conduit88after plug90. With reference toFIG. 12, the first drain conduit88can be seen above the second drain hole96such that the overflow from the second drain conduit88intersects the flow path of the first drain conduit88.

According to an exemplary embodiment illustrated inFIG. 11, there is a method for oiling an inside of a housing provided between an oil pump and a compressor. The method includes a step1100of attaching the housing between the oil pump and the compressor; a step1102of placing a crankshaft adapter inside a shell of the housing, the shell having a round cavity and the crankshaft adapter having at least one fin on an outer periphery of the crankshaft adapter; a step1104of establishing an oil feed conduit through the shell to penetrate into the round cavity for delivering oil from the oil pump; a step1106of forming a first drain conduit, opposite to the oil feed conduit, to enter through the shell into the round cavity and to drain the oil from the round cavity; a step1108of placing a plug in the first drain conduit to reduce an amount of oil drained away from the round cavity; and a step1110of establishing a second drain conduit through the shell into the round cavity to drain away oil from the round cavity. The second drain conduit is located between the oil feed conduit and the first drain conduit, substantially between 50 and 130 degrees relative to the first drain conduit.

The disclosed exemplary embodiments provide a system and a method for lubricating a connection between an oil pump and a compressor. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which are included in the spirit and scope of the invention as defined by the appended claims. Further, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a comprehensive understanding of the claimed invention. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.