Refrigerant heat exchanger

Abstract

A refrigerant heat exchanger is provided and includes: a hollow container having a cylindrical shape; a plate stack disposed on an inner lower side of the hollow container, including plates each having a front side and a back side with a plurality of concavo-convex portions formed thereon which are stacked to form a first heat exchange flow passage through which a first refrigerant flows and a second heat exchange flow passage through which a second refrigerant flows; a supply pipe disposed in an interior space of the hollow container above the plate stack and configured to supply the first refrigerant to the plate stack; and a discharge pipe configured to exchange heat between the first refrigerant supplied from the supply pipe and the second refrigerant flowing through the plate stack and to discharge the first refrigerant.

Claims

1. A refrigerant heat exchanger, comprising: a hollow container, having a cylindrical shape; a plate stack, disposed on an inner lower side of the hollow container, and the plate stack including: plates, each having a front side and a back side with a plurality of concavo-convex portions formed thereon, and the plates are stacked to form a plurality of first heat exchange flow passages through which a first refrigerant flows and a plurality of second heat exchange flow passages through which a second refrigerant flows; a supply pipe, disposed in an interior space of the hollow container above the plate stack and configured to supply the first refrigerant to the plate stack; and a discharge pipe, configured to exchange heat between the first refrigerant supplied from the supply pipe and the second refrigerant flowing through the plate stack and to discharge the first refrigerant, wherein a lower side of the plates of the plate stack has a semi-circular shape along and adjacent to an inner wall surface of the hollow container, wherein an upper side of the plates has a flattened shape having a greater curvature radius than a curvature radius of the semi-circular shape, wherein a second introduction hole which extends in a plate-stacking direction and into which the second refrigerant is introduced is disposed in an upper portion of the plate stack, and a second lead-out hole which extends in the plate-stacking direction and from which the second refrigerant is led out is disposed in a lower portion of the plate stack, wherein each of the second heat exchange flow passages comprises: a condensing flow passage extending linearly toward a side portion of the plates downward from the second introduction hole, in a view in the plate-stacking direction; and a discharge flow passage connected with the condensing flow passage via a bend portion and extending linearly toward the second lead-out hole downward, in the view in the plate-stacking direction, wherein the first heat exchange flow passage is formed so as to extend toward an end portion, with respect to a width direction, of the plates upward from the second lead-out hole, in the view in the plate-stacking direction, wherein an inclination angle of an extending direction of the condensing flow passage is smaller than an inclination angle of an extending direction of the discharge flow passage, and wherein the condensing flow passages of two or more of the second heat exchange flow passages are arranged one above the other between the second introduction hole and the second lead-out hole positioned below the second introduction hole.

2. The refrigerant heat exchanger according to claim 1, wherein the plate stack is configured such that, when the concavo-convex portions formed on respective adjacent plates are in contact with each other, the first heat exchange flow passages and the second exchange flow passages are formed by a corresponding valley between protruding portions of the adjacent concavo-convex portions and by a corresponding groove inside a recessed portion.

3. The refrigerant heat exchanger according to claim 1, wherein a restriction concavo-convex portion for restricting downward movement of the second refrigerant supplied from the second introduction hole is formed below the second introduction hole formed on the plates.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1A and FIG. 1B are diagrams of a heat exchanger according to an embodiment of the present invention. FIG. 1A is a side view of a heat exchanger, and FIG. 1B is a cross-sectional view corresponding to the I-I arrow view of FIG. 1A.

(2) FIG. 2A and FIG. 2B are diagrams of a NH.sub.3 introduction pipe according to an embodiment of the present invention. FIG. 2A is a side view and FIG. 2B is a bottom view of the NH.sub.3 introduction pipe.

(3) FIG. 3 is a front view of a plate according to an embodiment of the present invention.

(4) FIG. 4 is a front view of the plate in FIG. 3 turned over and showing the opposite side.

(5) FIG. 5A and FIG. 5B are diagrams of a NH.sub.3 introduction pipe according to another embodiment. FIG. 5A is a side view and FIG. 5B is a bottom view of the NH.sub.3 introduction pipe.

DETAILED DESCRIPTION

(6) Embodiments of the present invention will now be described with reference to FIG. 1A to FIG. 5B. It is intended, however, that unless particularly specified, materials, shapes, relative positions and the like of components described in the embodiments shall be interpreted as illustrative only and not intended to limit the scope of the present invention. In the present embodiment, a CO.sub.2 liquefier for liquefying vaporized CO.sub.2 will be described as an example of refrigerant heat exchanger.

(7) As shown in FIG. 1A and FIG. 1B, the refrigerant heat exchanger 1 constitutes a shell-and-plate heat exchanger, and is configured to exchange heat between a NH.sub.3 refrigerant liquid, which is a primary refrigerant, and a CO.sub.2 refrigerant gas, which is a secondary refrigerant, so that the NH.sub.3 refrigerant absorbs heat from the CO.sub.2 refrigerant and vaporizes, and the CO.sub.2 refrigerant liquefies.

(8) The refrigerant heat exchanger 1 includes a hollow container 5 having a cylindrical shape and a circular cross section, a plate stack 10 housed in an inner lower section of the hollow container 5, a NH.sub.3 supply pipe 30 disposed in an interior space 5a of the hollow container 5 above the plate stack 10 for supplying the plate stack 10 with the NH.sub.3 refrigerant liquid, and a NH.sub.3 discharge pipe 40 for discharging a NH.sub.3 gas generated from heat exchange between the NH.sub.3 refrigerant liquid supplied from the NH.sub.3 supply pipe 30 and a CO.sub.2 gas refrigerant flowing through the plate stack 10.

(9) The plate stack 10 is formed of a plurality of plate-shaped plates 11 stacked onto one another to have a substantially oval shape in a side view. The detail of the plate stack 10 will be described below specifically. A NH.sub.3 introduction opening 31 is formed on one side, in the width direction, of the upper part of a side wall 5c on one end side, in the axial direction, of the hollow container 5. The NH.sub.3 supply pipe 30 is inserted into the NH.sub.3 introduction opening 31. The NH.sub.3 supply pipe 30 includes a NH.sub.3 introduction pipe 32 inserted into the NH.sub.3 introduction opening 31, and a NH.sub.3 spray pipe 33 connected to the tip of the NH.sub.3 introduction pipe 32.

(10) The NH.sub.3 spray pipe 33 is disposed substantially parallel along an upper wall 5b of the hollow container 5. As shown in FIG. 2A and FIG. 2B, the NH.sub.3 spray pipe 33 includes a short-axis spray pipe 33a extending bended from the NH.sub.3 introduction pipe 32, and a long-axis spray pipe 33b extending bended from an end portion of the short-axis spray pipe 33a. A plurality of spray holes 33c having a small diameter are formed in two rows in the axial direction of the spray pipes, on the lower faces of the short-axis spray pipe 33a and the long-axis spray pipe 33b. The spray holes 33c are formed to face downward.

(11) On the upper part of the side wall 5c of one end side of the hollow container 5, as shown in FIG. 1A and FIG. 1B, a NH.sub.3 lead-out opening 41 is formed, and the NH.sub.3 discharge pipe 40 is inserted into the NH.sub.3 lead-out opening 41. The NH.sub.3 discharge pipe 40 extends to a position close to the inner surface of a side wall 5d on the opposite end side of the hollow container 5 along the axial direction of the hollow container 5, and has an opening portion 40a formed on the opposite end portion of the NH.sub.3 discharge pipe 40. Thus, the vaporized NH3 refrigerant gas flows out from the NH.sub.3 discharge pipe 40 via the opening portion 40a.

(12) A CO.sub.2 introduction opening 50 is disposed in the center part of the side wall 5c of the hollow container 5. A CO.sub.2 introduction pipe 51 is inserted into the CO.sub.2 introduction opening 50. The CO.sub.2 introduction pipe 51 is in communication with a CO.sub.2 introduction hole 13 formed inside the plate stack 10.

(13) A CO.sub.2 lead-out opening 53 is formed on the side wall 5c on a side of the hollow container 5 below the CO.sub.2 introduction pipe 51. A CO.sub.2 lead-out pipe 54 is inserted into the CO.sub.2 lead-out opening 53. The CO.sub.2 lead-out pipe 54 is in communication with a CO.sub.2 lead-out hole 15 formed inside the plate stack 10.

(14) The plates 11 forming the plate stack 10 are formed of sheet metal (e.g. stainless steel sheet). As shown in FIG. 1B and FIG. 3, in the axial directional view of the hollow container 5, the plates 11 are formed asymmetrically in the vertical direction with respect to the horizontal line H passing through the axial center S of the hollow container 5. That is, the plate 11a below the axial center S of the hollow container 5 is formed into a semi-circular shape along and adjacent to an inner wall surface 5e of the hollow container 5, the plate 11a having a curvature radius centered at a position below the axial center S of the hollow container 5. Furthermore, the plate 11b above the axial center S of the hollow container 5 is formed into a flattened shape (semi-oval shape), the plate 11b having a curvature radius greater than the curvature radius centered at the axial center S of the hollow container 5.

(15) As shown in FIG. 3 and FIG. 4, each of the plates 11 forming the plate stack 10 has a plurality of concavo-convex portions 17 formed on a front side and a back side of the plate 11. The plate stack 10 includes the plate 11 shown in FIG. 3 and the plate 11 shown in FIG. 4 stacked alternately. The plate 11 shown in FIG. 4 is the opposite side of the plate 11 shown in FIG. 3. Accordingly, the plate 11 shown in FIG. 4 has a configuration similar to that of the plate 11 shown in FIG. 3, and thus the plate 11 shown in FIG. 4 is associated with the same reference numerals as FIG. 3 at the same features to simplify the description.

(16) As shown in FIG. 3, the CO.sub.2 introduction hole 13 having a circular opening is disposed on the upper center part, in the width direction, of the plate 11. The CO.sub.2 lead-out hole 15 having a circular opening is disposed on the lower center part, in the width direction, of the plate 11.

(17) The concavo-convex portions 17 include a plurality of recessed portions 18 extending linearly and inclined (at an inclination angle of approximately 25 degrees) diagonally to the upper right side, formed in a region excluding the lower right section on the surface of the plate 11, and a plurality of protruding portions 19 extending linearly and diagonally to the upper right side having a greater inclination angle (approximately 60 degrees) than the recessed portions 18, formed in a region at the lower right section of the plate 11. The plurality of recessed portions 18 are formed parallel to one another at a predetermined interval, and the plurality of protruding portions 19 are formed parallel to one another at a predetermined interval.

(18) When the plate 11 shown in FIG. 4 is stacked on the opposite side of the plate 11 shown in FIG. 3, two independent heat exchange flow passages are formed on the front side and the back side of the plates 11, 11: the first heat exchange flow passage 21 and the second heat exchange flow passage 22. The first heat exchange flow passage 21 is formed on the front side of the plate 11 shown in FIG. 3, extending toward the right end portion, in the width direction, of the plate 11, upward from the CO.sub.2 lead-out hole 15. The first heat exchange flow passage 21 is formed by the valley between adjacent protruding portions 19 of the concavo-convex portions 17, and by grooves inside the recessed portions 18. Thus, the first heat exchange flow passage 21 is formed as a flow passage facing obliquely upward from one side toward the other side in the width direction of the plate 11.

(19) Furthermore, the second heat exchange flow passage 22 is formed on the front side of the plate 11 shown in FIG. 4, extending and bending toward the right side portion and the left side portion of the plate 11 downward from the CO.sub.2 introduction hole 13, and extending toward the CO.sub.2 lead-out hole 15 downward. The second heat exchange flow passage 22 is formed by the valley between the projecting portions 18a, projecting toward the bottom surface side, of the recessed portions 18 of the plate 11 shown in FIG. 4 and the valley between the protruding portions 19 shown in FIG. 3, and by the valley between the projecting portions 18a, protruding toward the bottom surface side, of the recessed portions 18 of the plate 11 shown in FIG. 3 and the valley between the protruding portions 19 of the plate 11 shown in FIG. 4.

(20) The second heat exchange flow passage 22 includes a condensing flow passage 22a extending linearly toward the side portion of the plate 11 downward and a discharge flow passage 22b extending linearly toward the CO.sub.2 lead-out hole 15 downward. Furthermore, the inclination angle in the extending direction of the condensing flow passage 22a is smaller than the inclination angle of the extending direction of the discharge flow passage 22b. Thus, the flow of the CO.sub.2 gas refrigerant supplied from the CO.sub.2 introduction hole 13 is slow at first, and then gets faster. Thus, it is possible to enhance the effect to transmit heat to the NH.sub.3 refrigerant liquid from the CO.sub.2 gas refrigerant, and to let the cooled CO.sub.2 refrigerant liquid flow through the CO.sub.2 lead-out hole 15 quickly. Accordingly, it is possible to provide a refrigerant heat exchanger 1 having a high heat-transmitting efficiency.

(21) Further, a restriction concavo-convex portion 20 for restricting downward movement of the CO.sub.2 gas refrigerant supplied from the CO.sub.2 introduction hole 13 is formed below the CO.sub.2 introduction hole 13 formed on the plate 11 shown in FIG. 3. The restriction concavo-convex portion 20 is formed into an arc shape so as to surround the outer periphery of the lower part of the CO.sub.2 introduction hole 13. The restriction concavo-convex portion 20 is formed into a protruding shape as seen from the back side of the plate 11.

(22) Further, a restricting concavo-convex portion 20 is formed below the CO.sub.2 introduction hole 13 formed on the plate 11 shown in FIG. 4. This restriction concavo-convex portion 20 is formed in an arc shape so as to surround the outer periphery of the lower part of the CO.sub.2 introduction hole 13, and has a protruding shape as seen from the front side of the plate 11. When the plates 11, 11 are stacked, the bottom portions of the restriction concavo-convex portion 20 shown in FIG. 3 and the restriction concavo-convex portion 20 of the plate 11 shown in FIG. 4 make contact, and an arc-shaped wall is formed below the CO.sub.2 introduction hole 13. Thus, it is possible to restrict downward movement of the CO.sub.2 gas refrigerant supplied from the CO.sub.2 introduction hole 13. Thus, it is possible to forcedly move the flow of the CO.sub.2 gas refrigerant supplied from the CO.sub.2 introduction hole 13 outward in the width direction of the plates 11, 11, and thereby it is possible to prevent a decrease in the heat-transmitting efficiency in advance.

(23) The above plates 11, 11 are integrated by connecting the outer peripheries of a plurality of plates 11, 11 by welding or the like while the plates 11, 11 are in a stacked state. The concavo-convex portions 17 are formed by press processing.

(24) In the refrigerant heat exchanger 1 with the above configuration, the CO.sub.2 gas refrigerant supplied from the CO.sub.2 introduction pipe 51 flows through the second heat exchange flow passage 22 of the plates 11, 11, and exchanges heat with the NH.sub.3 liquid refrigerant flowing through the first heat exchange flow passage 21 to become the CO.sub.2 refrigerant liquid, before flowing out of the CO.sub.2 lead-out pipe 54 via the second heat exchange flow passage 22.

(25) As described above, with the refrigerant heat exchanger 1, the second heat exchange flow passage 22 is configured to extend and bend toward the end portion, in the width direction, of the plates 11, 11 downward from the CO.sub.2 introduction pipe 51, as seen in the plate-stacking direction, and to extend toward the CO.sub.2 lead-out hole 15 downward, while the first heat exchange flow passage 21 is configured to extend toward the end portion, in the width direction, of the plates 11, 11 upward from the CO.sub.2 lead-out hole 15, as seen in the plate-stacking direction. Thus, both of the first heat exchange flow passage 21 and the second heat exchange flow passage 22 have a simple structure. Accordingly, the structure of the refrigerant heat exchanger 1 is simplified, and it is possible to provide a refrigerant heat exchanger 1 capable of suppressing an increase in the production costs.

(26) Furthermore, when stacking adjacent plates 11, 11, the first heat exchange flow passage 21 and the second heat exchange flow passage 22 are formed by the valley between the protruding portions 19 of the adjacent concavo-convex portions 17 and the grooves inside the recessed portions 18, which makes it possible to further facilitate production of the refrigerant heat exchanger 1.

(27) Furthermore, while the above described embodiment includes the NH.sub.3 spray pipe 33 having the short-axis spray pipe 33a extending and bending from the NH.sub.3 introduction pipe 32 and the long-axis spray pipe 33b extending and bending from an end portion of the short-axis spray pipe 33a (see FIG. 2B), a communication pipe 35 capable of supplying the NH.sub.3 liquid refrigerant and in communication with the NH.sub.3 introduction pipe 32 may be connected to the intermediate section, in the longitudinal direction, of the long-axis spray 33b having substantially the same length as the axial direction of the plate stack 10, as shown in FIG. 5A and FIG. 5B. With this configuration, the NH.sub.3 liquid refrigerant can be supplied even more uniformly to the plate stack 10.