The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 12, 2001
Filed:
Sep. 08, 1999
Yasutaka Yoshida, Shimizu, JP;
Susumu Nakayama, Shizuoka, JP;
Koji Naito, Shimizu, JP;
Satoru Yoshida, Shimizu, JP;
Hiroshi Takenaka, Shimizu, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An air conditioner comprising a refrigerant forward path branching on a discharge side of a compressor in an outdoor unit, one of the branched portions being defined by connecting a first four-way valve, a first outdoor heat exchanger and a first outdoor expansion valve to one another in this order, and the other of the branched portions being defined by connecting a second four-way valve, a second outdoor heat exchanger and a second outdoor expansion valve in this order, the path extending to an indoor unit from the respective outdoor expansion valves through a liquid-side piping, and returning to the outdoor unit from the indoor unit through a gas-side piping to branch, one of the branched portions being connected to the first four-way valve via a check valve placed in communication in a forward direction and the other of the branched portions being connected to the second four-way valve, the air conditioner being controlled such that, when heating operation is switched to defrosting operation, the second four-way valve is switched if a pressure difference between discharge pressure and suction pressure of the compressor is equal to or above a predetermined value, and the first four-way valve is switched after a gas-side pressure of the second outdoor heat exchanger has risen, whereby the four-way valves are prevented from being made inoperative due to short-circuit between high pressure side and low pressure side.