Plate heat exchanger and heat pump apparatus

Abstract

A plate heat exchanger includes: a plurality of heat transfer plates including first to fourth through-holes to extend through the heat transfer plate, stacked in a single direction to isolate first and second water flow passages; and end plates including first and second inlet and outlet ports, and a connection port, that the heat transfer plates are sandwiched between The first inlet and outlet port, continuous with the first and second through-holes, allow a first fluid to flow into and out of the first flow passage. The second inlet and outlet port, continuous with the third and fourth through-holes, allow a second fluid to flow into and out of the second flow passage. The connection port is connected to a pressure relief valve provided separately from the plate heat exchanger.

1 . A plate heat exchanger comprising:
 a plurality of heat transfer plates in each of which a first through-hole, a second through-hole, a third through-hole, and a fourth through-hole are provided to extend through the heat transfer plate in a single direction, the plurality of heat transfer plates being stacked together in the single direction, configured to isolate a first flow passage through which a first fluid flows and a second flow passage through which a second fluid flows, and configured to cause heat exchange to be performed between the first fluid in the first flow passage and the second fluid in the second flow passage;   a pair of end plates in which a first inlet port, a first outlet port, a second inlet port, a second outlet port, and a connection port are provided, the pair of end plates being provided such that the plurality of heat transfer plates are sandwiched between the pair of end plates in the single direction, the first inlet port being continuous with the first through-holes and located as a port through which the first fluid flows into the first flow passage, the first outlet port being continuous with the second through-holes and located as a port through which the first fluid flows out from the first flow passage, the second inlet port being continuous with the third through-holes and located as a port through which the second fluid flows into the second flow passage, the second outlet port being continuous with the fourth through-holes and located as a port through which the second fluid flows out from the second flow passage, the connection port being continuous with the first through-holes or the second through-holes, and branching off from the first flow passage,   wherein the connection port is connected to a pressure relief valve provided separately from the plate heat exchanger,   the plate heat exchanger further comprising a temperature sensor configured to detect a temperature related to the first fluid that flows in the plate heat exchanger, the temperature sensor being attached to one of the end plates that includes the connection port.   
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The plate heat exchanger of  claim 1 , wherein
 in the end plate including the connection port, at least one of the first inlet port, the first outlet port, the second inlet port, and the second outlet port is provided, and   a distance between the connection port and the temperature sensor is smaller than a distance between the temperature sensor and each of the first inlet port, the first outlet port, the second inlet port, and the second outlet port that are provided in the end plate including the connection port.   
     
     
         5 . The plate heat exchanger of  claim 1 , wherein as viewed from a direction perpendicular to a surface of the end plate including the connection port, the temperature sensor is located between the connection port and an end portion of the end plate, and none of the first inlet port, the first outlet port, the second inlet port, and the second outlet port is provided between the connection port and the end portion of the end plate. 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . The plate heat exchanger of  claim 1 , wherein a flow-passage sectional area of the connection port is greater than a flow-passage sectional area of the first outlet port. 
     
     
         9 . A heat pump apparatus comprising:
 a refrigerant circuit in which a compressor, a plate heat exchanger, an expansion mechanism, and a heat-source-side heat exchanger are connected by refrigerant pipes to circulate refrigerant;   a heat medium circuit in which a pump, the plate heat exchanger, and a use-side heat exchanger are connected by heat medium pipes to circulate a heat medium;   a pressure relief valve connected to a connection port that branches off from part of the heat medium circuit that is located in the plate heat exchanger, the pressure relief valve being provided separately from the plate heat exchanger; and   a temperature sensor configured to detect a temperature related to the heat medium that flows in the plate heat exchanger,   wherein the plate heat exchanger includes
 a plurality of heat transfer plates in each of which a first through-hole, a second through-hole, a third through-hole, and a fourth through-hole are provided to extend through the heat transfer plate in a single direction, the plurality of heat transfer plates being stacked together in the single direction, configured to isolate a first flow passage through which the heat medium flows and a second flow passage through which the refrigerant flows, and configured to cause heat exchange to be performed between the heat medium in the first flow passage and the refrigerant in the second flow passage, and 
   a pair of end plates in which a first inlet port, a first outlet port, a second inlet port, a second outlet port, and the connection port are provided, the first inlet port being continuous with the first through-holes and located as a port through which the heat medium flows from the heat medium pipe into the first flow passage, the first outlet port being continuous with the second through-holes and located as a port through which the heat medium flows out from the first flow passage to the heat medium pipe, the second inlet port being continuous with the third through-holes and located as a port through which the refrigerant flows from the refrigerant pipe into the second flow passage, the second outlet port being continuous with the fourth through-holes and as a port through which the refrigerant flows out from the second flow passage to the refrigerant pipe, the connection port being located continuous with the first through-holes and opposite to the first inlet port or being located continuous with the second through-holes and opposite to the first outlet port, and   wherein the temperature sensor is attached to one of the end plates that includes the connection port.   
     
     
         10 . (canceled) 
     
     
         11 . The heat pump apparatus of  claim 9 , or further comprising:
 a temperature sensor configured to detect a temperature related to the heat medium that flows in the plate heat exchanger; and   a controller connected to the temperature sensor and the compressor such that the controller is allowed to communicate with the temperature sensor and the compressor,   wherein the controller stops the compressor when a temperature detected by the temperature sensor is less than a predetermined threshold.   
     
     
         12 . The heat pump apparatus of  claim 9 , wherein the pressure relief valve is opened when a pressure in the heat medium circuit exceeds a predetermined set value, and the pressure relief valve is closed when the pressure in the heat medium circuit is less than or equal to the set value after the pressure relief valve is opened. 
     
     
         13 . The heat pump apparatus of  claim 9 , wherein the pressure relief valve is provided in an outdoor space. 
     
     
         14 . The heat pump apparatus of  claim 9 , wherein an outflow pipe configured to allow a fluid that flows out from the pressure relief valve to flow out to an outdoor space is connected to the pressure relief valve. 
     
     
         15 . The heat pump apparatus of  claim 9 , wherein in the heat medium, a check valve is provided between the pump and the plate heat exchanger. 
     
     
         16 . The plate heat exchanger of  claim 1 , wherein the first inlet port and the first outlet port are both provided in a same one of the end plates, and the connection port is provided in a remaining one of the end plates. 
     
     
         17 . The heat pump apparatus of  claim 9 , wherein in the plate heat exchanger, the first inlet port and the first outlet port are both provided in a same one of the end plates, and the connection port is provided in a remaining one of the end plates.