PLATE HEAT EXCHANGER AND WATER HEATER INCLUDING SAME

• US 20200132397A1
• Filed: 10/16/2019
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: Noritz Corporation
• Original Assignee: Noritz Corporation
• Inventors: NISHIMURA, Kazuhiro, SUGIE, Shigeo, NAKAYAMA, Kenichi
• Granted Patent: US 11,060,761 B2
• Time in Patent Office: Days
• CPC Class Codes: F24H 1/38 with water contained in separate elements, e.g. radiator-type element
• CPC Class Codes: F24H 8/00 Fluid heaters characterised by means for extracting latent heat from flue gases by means of condensation
• CPC Class Codes: F24H 9/0005 for water heaters
• CPC Class Codes: F24H 9/146 Connecting elements of a heat exchanger
• CPC Class Codes: F28D 21/0007 Water heaters
• CPC Class Codes: F28D 9/0043 the plates having openings therein for circulation of at least one heat-exchange medium from one conduit to another
• CPC Class Codes: F28D 9/0062 the conduits for one heat-exchange medium being formed by spaced plates with inserted elements F28D9/0012, F28D9/0025, F28D9/0081, F28D9/04 take precedence
• CPC Class Codes: F28D 9/0093 Multi-circuit heat-exchangers, e.g. integrating different heat exchange sections in the same unit or heat-exchangers for more than two fluids
• CPC Class Codes: F28F 9/0282 by varying the geometry of conduit ends, e.g. by using inserts or attachments for modifying the pattern of flow at the conduit inlet or outlet
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A plate heat exchanger includes a plurality of plates stacked so that a liquid flow passage is formed on the inside thereof, and a gas flow passage through which heating gas passes, the gas flow passage being formed between the plurality of plates and including a gas inflow opening portion and a gas outflow opening portion positioned on an opposite side to the gas inflow opening portion, wherein the gas outflow opening portion has a smaller opening area than the gas inflow opening portion. Thus, when the heating gas passes through the gas flow passage, even if the volumetric flow thereof decreases due to a reduction in temperature or condensation, a reduction in the flow velocity of the heating gas can be suppressed. Hence, a reduction in a heat transfer coefficient can be suppressed, leading to an improvement in heat transfer efficiency, and as a result, reductions in overall size, weight, and manufacturing cost can be achieved appropriately.

Claims

1. A plate heat exchanger comprising:

a plurality of plates stacked so that a liquid flow passage is formed on the inside thereof; and

a gas flow passage through which heating gas passes, the gas flow passage being formed between the plurality of plates and including a gas inflow opening portion and a gas outflow opening portion positioned on an opposite side to the gas inflow opening portion, wherein

the gas outflow opening portion has a smaller opening area than the gas inflow opening portion.

2. The plate heat exchanger according to claim 1, wherein

each of the plates has a smaller width on the gas outflow opening portion side than the gas inflow opening portion side.

3. The plate heat exchanger according to claim 1, wherein

each of the plates is provided in an upright attitude in an up-down height direction, and

an inflow port of the liquid flow passage is provided in a lower portion of each of the plates on the side of a first end portion in a width direction, while an outflow port of the liquid flow passage is provided in an upper portion of each of the plates on the side of a second end portion opposing the first end portion in the width direction.

4. The plate heat exchanger according to claim 3, wherein

an upper end portion of each of the plates is inclined so that the second end portion has a greater height than the first end portion.

5. The plate heat exchanger according to claim 3, wherein

an upper end portion and a lower end portion of each of the plates are positioned respectively on an upstream side and a downstream side in a heating gas flow direction, and

the liquid flow passage includes a first region that surrounds the inflow port when seen from the front, and a first flow passage that extends linearly from the first region toward the upper end portion of the plate.

6. The plate heat exchanger according to claim 3, wherein

the liquid flow passage includes a second region that surrounds the outflow port when seen from the front, and a second flow passage that extends linearly from the second region toward a lower end portion of the plate.

7. The plate heat exchanger according to claim 1, wherein

outer peripheral end portions of the plurality of plates opposing each other on opposite sides of the gas flow passage are bonded to each other except in regions of the gas inflow opening portion and the gas outflow opening portion.

8. The plate heat exchanger according to claim 1, wherein

adjacent plates, among the plurality of plates, are brazed to each other, whereas regions near the center of plates that oppose each other on opposite sides of the gas flow passage are not brazed and therefore remain in a non-bonded state.

9. The plate heat exchanger according to claim 1, further comprising:

a flow-straightening member that covers a region of the outer periphery of the plurality of plates excluding the gas inflow opening portion and the gas outflow opening portion and prescribes respective opening widths of the gas inflow opening portion and the gas outflow opening portion.

10. The plate heat exchanger according to claim 1, wherein

a plurality of gas flow passages are provided as the gas flow passage, and

the gas outflow opening portion of each of the gas flow passages has a narrower width than the gas inflow opening portion.

11. A water heater comprising:

the plate heat exchanger according to claim 1.

12. The water heater according to claim 11, further comprising:

an exhaust gas guide member that is connected to a downstream side of the plate heat exchanger in a heating gas flow direction in order to cause heating gas that has passed through the plate heat exchanger to flow in a first direction intersecting the heating gas flow direction through the plate heat exchanger, wherein

the plate heat exchanger is set so that a stacking direction of the plurality of plates corresponds to a second direction that intersects the first direction.