Pumps – Condition responsive control of pump drive motor – Responsive to pump or pump fluid temperature
Reexamination Certificate
1998-03-23
2001-01-09
Yuen, Henry C. (Department: 3747)
Pumps
Condition responsive control of pump drive motor
Responsive to pump or pump fluid temperature
C418S055100
Reexamination Certificate
active
06171064
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to monitoring of the suction temperature of a scroll compressor to make a determination of when the compressor is running in reverse.
Scroll compressors are becoming widely utilized in many compression applications. Scroll compressors have high efficiency, and thus are becoming very popular. However, there are many challenges during scroll compressor operation.
Essentially, a scroll compressor includes a pair of interfitting scroll wraps each connected to a planar base. One of the wraps is fixed and the other wrap orbits relative to the fixed wrap. The wraps are in contact with each other and define compression chambers for an entrapped fluid. As the orbiting scroll moves relative to the fixed scroll, the size of the compression chambers change to compress the gas.
Scroll compressors are designed to operate in one direction. If there is orbiting movement of the orbiting scroll in the opposed direction, then the scroll compressor is not operating properly. There is unwanted noise, and increased heat in the compressor system. This is undesirable.
One main cause of reverse rotation in scroll compressors is miswiring of the motors. Often, scroll compressors are driven by three phase motors. The three phase motors typically include three power input lines leading from a power supply to the motor. If the lines are misconnected to the motor, then an improper phasing of the voltage may be supplied and the motor may run in reverse. As mentioned above, if a scroll compressor is ran in reverse, the results are undesirable.
SUMMARY OF THE INVENTION
When a scroll compressor is ran in reverse, there is noise and increased temperatures at many locations in the system. One location is the suction tube. Gas is no longer being drawn into the compressor. In fact, applicant has determined that a small quantity of gas passes out of the compressor and through the suction tube. When this occurs, the suction tube quickly reaches an elevated temperature. The housing around the tube also reaches an increased temperature.
The present invention monitors the temperature at or adjacent the suction tube. If a predetermined maximum suction temperature is exceeded, then a determination is made that reverse rotation is occurring. Once the determination is made, the motor is shut down. The motor may be shut down by a control directly to the motor, or the control may communicate to the power supply. As an example, phase reversing circuits are known wherein the phase of two of the three wires is changed. These circuits would result in proper wiring of the three phase motor should an improper connection be initially made. The phase circuits are activated by the temperature sensor.
In the preferred embodiment, the temperature sensor is one which moves from a monitoring position to an actuated position once a particular temperature is reached. As one example, the sensor may include a fusible element which melts when the target temperature is reached. As another example, the sensor may include a member which moves between one of two positions once the temperature is reached, such as a bi-metal snap disk. The sensor may include a manual reset, an automatic reset, or may be one which must be replaced after one actuation. The temperature in the suction tube or adjacent to the suction tube upon reverse rotation may approximate 300° F. The normal operating temperature should not exceed approximately 120° F. Thus, it is quite easy to design an element which will only be actuated upon reverse rotation.
In several embodiments, the sensor may be placed on the suction tube, or on the housing adjacent to the suction tube. Either location will be sufficient for identifying when reverse rotation is occurring.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
REFERENCES:
patent: 5118260 (1992-06-01), Fraser, Jr.
patent: 5186613 (1993-02-01), Kotlarek et al.
patent: 5368446 (1994-11-01), Rode
patent: 5452989 (1995-09-01), Rood et al.
patent: 5607288 (1997-03-01), Wallis et al.
patent: 5684463 (1997-11-01), Diercks et al.
patent: 5690475 (1997-11-01), Yamada et al.
Hugenroth Jason J.
Williams John R.
Carlson & Gaskey & Olds
Gimie Mahmoud M
Scroll Technologies
Yuen Henry C.
LandOfFree
Reverse rotation detection for scroll compressor utilizing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reverse rotation detection for scroll compressor utilizing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reverse rotation detection for scroll compressor utilizing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2541372