Scroll type compressor

Details Scroll type compressor Scroll type compressor

2002-01-22

2003-11-11

Denion, Thomas (Department: 3748)

Rotary expansible chamber devices

Working member has planetary or planetating movement

Helical working member, e.g., scroll

C418S083000

Reexamination Certificate

active

06644946

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a scroll type compressor, especially to a scroll type compressor that compresses gas to supply to a fuel cell.
There are compressors of various types, e.g. a screw type compressor, a rotary type compressor and a scroll type compressor. Particularly, the scroll type compressor is small and light, and generates less vibration and less noise. Therefore, the scroll type compressor is widely used for freezing and air-conditioning. The scroll type compressor produces heat in compression cycle. In a prior art as described in Japanese Unexamined Patent Publication No. 8-247056, a cooling chamber is provided around a discharge port to cool discharge gas.
FIG. 7
is a longitudinal cross-sectional view of a conventional scroll type compressor. A housing of the conventional compressor
100
is constituted of a front casing
101
, an end plate
102
and a rear casing
103
. The end plate
102
is connected to the front casing
101
on the side of a discharge port
104
. The rear casing
103
is connected to the front casing
101
on the side of a motor. The discharge port
104
is formed through the center of the end plate
102
. A cooling chamber
120
is defined between the front casing
101
and the end plate
102
. A fixed scroll wall
105
extends from a fixed scroll base plate
107
of the front casing
101
toward the side of the motor. Meanwhile, one end of a crank shaped drive shaft
109
, which is connected to a drive shaft of the motor, is rotatably arranged on the motor side of the rear casing
103
. A movable scroll wall
110
extends from a movable scroll base plate
111
toward the side of the discharge port. Compression chambers
106
are defined between the fixed scroll wall
105
and the movable scroll wall
110
. A discharge valve
108
separates the compression chambers
106
from the discharge port
104
.
As the drive shaft
109
rotates due to rotation of the motor, the movable scroll wall
110
orbits. Gas, such as air, in the compression chambers
106
is radially inwardly moved toward the innermost compression chamber
106
as is compressed. The gas heats in compression cycle. The compressed gas is discharge to the discharge port
104
via the discharge valve
108
, then outside the compressor
100
.
Cooling water flows into a cooling chamber
120
via a coolant inlet, which is not shown. The cooling chamber
120
is defined in the vicinity of the compression chambers
106
and the discharge port
104
. Therefore, the heat generated by compressing the gas in the compression chambers
106
and the heat of the compressed gas in the discharge port
104
conduct to the cooling water. The cooling water, temperature of which rose due to the heat conduction, flows outside the compressor
100
via the communicating passage, which is not shown.
In the conventional scroll type compressor, as shown in
FIG. 7
, parts of the compression chambers
106
are adjacent to the cooling chamber
120
via the fixed scroll base plate
107
. Therefore, the cooling water in the cooling chamber
120
warms the gas just flowed into outermost compression chambers.
Since the temperature of the suction gas has not risen yet, the temperature of the cooling water may be higher than the temperature of the suction gas. Therefore, in the conventional scroll type compressor, the cooling water warms the suction gas in the outermost compression chambers.
As the gas just flowed into the outermost compression chambers is warmed, the temperature of the compressed gas, or the temperature of the discharge gas, rises. As the temperature of the gas increased, density of the gas decreases. Therefore, mass flow of the gas (kg/hour) decreases. Consequently, compression efficiency decreases.
In the use of the discharged gas, predetermined mass of the gas should be ensured for unity time. Since mass of discharge air affects the amount of electricity generated by a fuel cell, for example, when the discharged air is used as an oxidizer, the fuel cell requires predetermined mass of the discharged air. In such a state, increasing a workload of the compressor can ensure enough mass flow of the discharged air. However, increasing the workload of the compressor causes the motor for driving the compressor to become large.
SUMMARY OF THE INVENTION
The present invention addresses the above-mentioned problems traceable to a loss of compression efficiency by restraining unwanted heat conduction.
According to the present invention, a scroll type compressor has a housing, a drive shaft, a fixed scroll member, a movable scroll member, a suction port and a discharge port. The drive shaft is rotatably supported by the housing. The fixed scroll member is fixed to the housing. The movable scroll member is accommodated in the housing, and faces the fixed scroll member. The housing and the fixed scroll member define a cooling region. The fixed scroll member and the movable scroll member define a compression region. The gas introduced via the suction port is compressed in the compression region by orbiting the movable scroll member relative to the fixed scroll member by rotation of the drive shaft, and the compressed gas is discharged from the compression region via the discharge port. Heat resistant means is disposed at least between the cooling region and the compression region. Heat resistance of the heat resistant means adjacent to the outermost compression region is greater than that of the heat resistant means adjacent to the innermost compression region.
The greater heat resistance of the outer heat resistant means relative to the heat resistance of the inner heat resistant means inhibits the suction gas from being warmed by coolant, such as cooling water, in the cooling region. Thereby, the temperature of the discharge gas is decreased.
Additionally, the term of the heat resistance in the present invention is a parameter indication the degree how heat is not conducted. Heat resistance is expressed by &Dgr;T/Q[K/W] where &Dgr;T is temperature differential between two points, the unit of which is Kelvin, or K. Q is the quantity of heat conduction, the unit of which is watt, or W. In the present invention, heat of the cooling region is conducted to the outermost compression region of the scroll type compressor. In terms of the heat conduction, heat resistance &agr; is expressed by &agr;−(T
1
−T
2
)/Q=&dgr;/(&lgr;·A) where T
1
and T
2
are temperature of both inner and outer surfaces of a solid wall, A is a cross section area of the solid wall. &dgr; is the thickness of the solid wall. Q is the quantity of transferred heat. Then, &lgr; is the heat conductivity.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.


REFERENCES:
patent: 5247738 (1993-09-01), Yoshii
patent: 5622487 (1997-04-01), Fukuhara et al.
patent: 5775888 (1998-07-01), Sakamoto et al.
patent: 6146575 (2000-11-01), Huston
patent: 62265487 (1987-11-01), None
patent: 04342801 (1992-11-01), None
patent: 05010281 (1993-01-01), None
patent: 05033784 (1993-02-01), None
patent: 06159267 (1994-06-01), None
patent: 8-247056 (1996-09-01), None

Affiliated with

Also associated with

Rating

Scroll type compressor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Scroll type compressor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Scroll type compressor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3140190