Gas separation – Plural serial basically diverse separating media – Plural stages in unitary casing
Reexamination Certificate
2002-01-25
2003-10-21
Hopkins, Robert A. (Department: 1724)
Gas separation
Plural serial basically diverse separating media
Plural stages in unitary casing
C055S385300, C055S447000, C055SDIG001, C096S189000
Reexamination Certificate
active
06635095
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an oil separator for separating the oil mist from gaseous fluids, such as a blowby gas, and in particular, to an oil separator which is suitably used in a gas engine for a gas heat pump type air conditioner.
2. Description of the Related Art
An air conditioner, in which a heat pump is used for cooling and heating operations, is provided with a refrigerant circuit comprising an indoor heat exchange apparatus, a compressor, an outdoor heat exchange apparatus, an expansion valve, etc. When the refrigerant circulates in the refrigerant circuit and exchanges heat with air in the indoor heat exchange apparatus and the outdoor heat exchange apparatus, the air conditioned chamber is heated or cooled. In addition, in order to heat the chamber, not only the outdoor heat exchange apparatus but also a refrigerant heating apparatus for heating the refrigerant directly is sometimes provided in the refrigerant circuit.
In recent years, an air conditioner has been suggested, which comprises a gas engine, instead of an ordinary motor, as a driving source for the compressor provided in the refrigerant circuit. An air conditioner utilizing a gas engine is called a gas heat pump type air conditioner (abbreviated as “GHP” below). The GHP can use gas, which is relatively cheap, as fuel; therefore, the running cost thereof can be reduced, compared with an air conditioner comprising a compressor driven by the ordinary motor (abbreviated as “EHP” below).
Moreover, in the GHP, when waste heat of gas at a high temperature discharged from the gas engine during the heating operation is used as the heat source for the refrigerant, the heating ability can be improved, and the use efficiency of energy can also be improved. In addition, when the waste heat of the gas discharged from the gas engine is used in the GHP, the GHP does not require a special device, such as the refrigerant heating device explained above.
Furthermore, the GHP can utilize the engine waste heat to defrost the outdoor heat exchange apparatus during the heating operation. In general, the EHP defrosts the outdoor heat exchange apparatus by stopping the heating operation and temporarily performing the cooling operation. That is, when the EHP defrosts, cooled air is introduced into the chamber. Therefore, a person in the chamber feels unpleasant. In contrast, the GHP can utilize the waste heat, and it can continuously perform the heating operation without such the problem which is caused by the EHP.
The GHP has many advantages as explained above; however, it also has the following problems.
As explained above, the GHP uses the gas engine as a driving source for the compressor. In the gas engine, oil contained in the blowby gas may rise to problems. The blowby gas is gas which leaks from the combustion chamber into a crank case through a gap between the piston ring and the cylinder. In general, the blowby gas is returned from the crank case into an engine intake system and is then sent to the combustion chamber again.
Since the blowby gas contains a lubricating oil in a the state of a mist (abbreviated as “oil mist” below), at a suitable positions on a line for the flow of the blowby gas (abbreviated as “blowby gas line” below), oil separators for accumulating and removing the oil mist, such as a blowby gas filter, are provided.
FIGS. 11
,
12
A, and
12
B show a conventional oil separator which is used as a blowby gas filter. In the figures, reference number
140
denotes an oil separator,
141
denotes a case body,
142
denotes a lid,
143
denotes a filter,
144
denotes gaseous fluid entrance,
145
denotes a gaseous fluid exit, and
146
denotes an outflow exit for the oil mist accumulated by the filter
143
. Moreover, the case body
141
and the lid
142
comprise the casing of the oil separator
140
.
In the oil separator
140
, the blowby gas, which flows in through the entrance
144
connected to the crank case of the gas engine, passes through the filter
143
and is sucked through the exit
145
by the intake system of the gas engine. The oil mist contained in the blowby gas is separated and removed as it passes through the filter
143
, falls to the bottom of the case body
141
, and is then returned to the oil pan of the gas engine through the outflow exit
146
. In the oil separator
140
, in order to improve the separation efficiency of the oil mist, the height of the filter
143
, through which the blowby gas passes, is increased as much as possible. It is necessary to replace the filter
143
after a given operation time of the oil separator
140
. Therefore, in order to change the filter
143
, the lid
142
can detach from the case body
141
. In addition, in order to easily change the filter
143
, the lid
142
is attached at the side of the case body
141
, where an opening having the largest area can be formed.
However, if the lid
142
is formed at the side of the case body
141
, there is the possibility that the oil falling to the bottom of the case body
141
will leak from a gap between the case body
141
and the lid
142
. In particular, when the oil mist contained in the blowby gas is separated and removed in the oil separator
140
, the pressure at the bottom of the case body
141
where the outflow exit
146
is provided is greater than the atmospheric pressure at the outside of the case body
141
. That is, the pressure at the bottom of the case body
141
where the outflow exit
146
is provided in a positive pressure region. Therefore, there may be oil leak due to the pressure difference, at any gap occurring at the contact portion.
An oil leakage can be solved by improving the seal between the case body
141
and the lid
142
. However, in order to obtain a good seal, the structure of the contact portion must be complicated; therefore, a cost for manufacturing the oil separator will increase. In addition, since the case body
141
and the lid
142
are made of synthetic resins, if the structure thereof is complicated, their formability may be decreased.
In addition, in the conventional oil separator
140
, since the filter
143
is made of nonwoven fabrics, which have inferior shape maintaining properties, there is the problem that a gap S can easily occur between the filter
143
and the inside wall of the case body
141
, as shown in FIG.
12
A. If the gap S is generated, the blowby gas containing the oil mist passes through the gap S and flows out through the exit
145
, without passing through the filter
143
. The gap S decreases the separation efficiency of the oil mist in the oil separator
140
. Therefore, it is desired for the blowby gas to pass with certainty through the filter
143
. In addition, in the conventional oil separator
140
, since the separation of the oil mist is carried out by only the filter
143
, there is the problem that it is difficult to obtain a sufficient separation efficiency. In this case, the separation efficiency can be improved by increasing the thickness of the filter
143
. However, an increase in the thickness of the filter
143
causes a significant pressure loss. Therefore, the separation efficiency cannot be sufficiently improved only by increasing the thickness of the filter
143
. In the light of the above, it is desired to provide oil separator in which the oil mist contained in the blowby gas can be efficiently separated without increasing the pressure loss.
Therefore, one of objects of the present invention is to improve the performances of the oil separator for removing the oil mist from the gaseous fluids, such as the blowby gas. In particular, an object of the present invention is to provide an oil separator which can be manufactured at a low cost and can prevent the leakage of removed oil, and an oil separator which has improved separation efficiency of the oil mist contained in the gaseous fluids without increasing the pressure loss.
SUMMARY OF THE INVENTION
In order to achieve the object, the present invention provides an oil separator for separating oil from a g
Hopkins Robert A.
Mitsubishi Heavy Industries Ltd.
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