JPH0249516Y2 - - Google Patents

Description

[Detailed description of the invention] Application industry field This invention relates to an open rack type evaporator for vaporizing liquefied natural gas, and prevents the bowing phenomenon that occurs in the lower header tank of the heat exchange panel during steady operation and This invention relates to an evaporator that achieves stability during transient operation and extends the life of panels.

BACKGROUND TECHNOLOGY An open rack type evaporator, for example, has a finch tube with a pair of fins protruding in the diametrical direction arranged in the direction of the fins to form a single panel, and header tanks are provided at the top and bottom ends of the finch tube to form a heat exchange panel. The structure is such that a plurality of panels are arranged in parallel, and seawater as a heat medium flows down onto the heat exchange panel surface from a water sprinkler placed above each panel.

In a conventional evaporator, during operation, the heat medium such as seawater sprinkled is scattered on the upper outer periphery of the horizontally arranged lower header tank, reducing the amount of heat medium flowing down to the lower outer periphery. Due to the temperature difference in the vertical direction, the so-called bowing phenomenon occurs, where the header tank deforms into an arched shape.
The lower part of the fin fin tube, especially the part where the fins are removed during assembly due to welding with the header tank during assembly, may be bent, and there is a risk of damage to this part and the equipment due to increased stress due to the change in shape due to fin removal. There were problems with durability.

In addition, in order to prevent this Boeing phenomenon,
A technique has been proposed (Japanese Patent Publication No. 56-34758) in which a heat-insulating structure is attached to the lower header tank to limit heat input from the outside.

However, in the above evaporator, when seawater is sprinkled as a heat medium and liquefied natural gas is vaporized,
During the transition period of starting and stopping the equipment, due to the density difference between the gas and liquid liquefied natural gas, the low-temperature liquid natural gas comes into contact only with the lower inner peripheral surface of the lower header tank. This generates a large temperature difference in the vertical direction and is insufficient to prevent the bowing phenomenon. Further, the above-mentioned heat-insulating structure may cause problems such as corrosion of the structural material by seawater.

Purpose of the invention In view of the above-mentioned current situation, the purpose of this invention is to create an open rack type evaporator that can prevent the bowing phenomenon that occurs in the lower header tank, extend the life of the panel, and has a simple structure and easy installation. There is.

Structure of the device In this device, a heat exchange panel is constructed by arranging finch tubes with one or more pairs of fins protruding in the diametrical direction and arranging them in the direction of the fins to form a single panel, and providing header tanks at the top and bottom ends of the fins. A plurality of heat exchange panels are arranged in parallel, and the ends of each lower header tank are orthogonally connected to provide a manifold for distributing and supplying liquefied gas to each heat exchange panel. In an open rack type evaporator that evaporates the liquefied gas in the tube by causing the heat medium, seawater, to flow down from the installed water sprinklers onto the heat exchange panel surface, a heat receiving member is attached to at least one location in the longitudinal direction of the bottom surface of each lower header tank. This is an open rack type evaporator characterized by the following.

This idea is achieved by attaching a heat-receiving member such as a heat-receiving plate to at least one place on the lower surface of the lower header tank of the heat exchange panel, for example, at a required length in the longitudinal direction from the lower surface of the mounting part of the finch tube. As a result of reducing the temperature difference between the upper and lower surfaces of the lower header tank, stress on the lower fin cut portion of the finch tube due to the bowing phenomenon that occurs due to the temperature difference between the upper and lower surfaces of the lower header tank is reduced.
This prevents damage to the finch tube attachment part and improves the durability of the heat exchange panel.Although the structure is simple, it is highly effective in eliminating the temperature difference between the upper and lower surfaces of the lower header tank. It has the advantage of being inexpensive and easy to install, regardless of whether it is a new installation.

In this invention, the heat receiving member provided on the lower surface of the lower header tank is one that actively inputs heat to the attached location, and if it is a plate material, plate piece, template material, etc. that can give heat to the header tank,
The material and shape do not matter, but it is necessary to select the shape and material appropriately according to the structure and dimensions of the heat exchange panel so as not to interfere with heat exchange during operation and to prevent deformation. be.

In this invention, the heat receiving member is attached to the inlet of the lower header tank, the end cap on the opposite side thereof, or both, and also over the entire length of the lower surface of the lower header tank. It may be selected as appropriate depending on the temperature difference and its distribution on the lower surface, the configuration of the heat exchange panel, etc.

The heat receiving member may be attached in any manner as long as it can input heat from the heat receiving member to the header tank, such as integrally with the header tank, by welding, or fixed with a band or the like.

Disclosure of the invention based on drawings This invention will be described in detail below based on drawings of embodiments. FIG. 1 is a perspective explanatory view of an open rack type evaporator according to this invention. FIG. 2 is a perspective explanatory view of a lower header tank section showing heat receiving members of various shapes according to this invention.

As shown in FIG. 1, the open rack type evaporator has a finch tube having a plurality of pairs of fins protruding in the diametrical direction, arranged in the direction of the fins to form a single panel, and a header tank 2 at the upper and lower ends of the finch tube. 3 to form a heat exchange panel 1, a plurality of heat exchange panels 1 are suspended in parallel, and each upper header tank 2 and lower header tank 3 each has one manifold 4 (only the lower manifold is shown).
The structure is such that sea water as a heat medium flows down onto one surface of the heat exchange panels from a water sprinkler (not shown) disposed above each heat exchange panel 1.

Note that the lower end of the finch tube has no fins by cutting out the fins, and this finless portion is erected at the upper end of the outer circumference of the lower header tank 3 by welding.

A heat receiving member 10 made of a plate material is attached to the lower surface of each lower header tank 3. Here, an example is shown in which the heat receiving member 10 is attached only to a required length from the lower surface of the inlet side of the lower header tank 3 where the finch tube is erected to the end cap side. The following examples are also the same, but as described above, the invention is not limited thereto.

In the evaporator configured as described above, when the cryogenic liquefied gas distributed and supplied by the manifold 4 enters the lower header tank 3, as the seawater sprinkles and falls, there is a gap between the upper and lower surfaces of the lower header tank 3. Due to the temperature difference, the lower header tank 3 is deformed so that its inlet side arches downward.

However, the heat receiving member 10 is not connected to the lower header tank 3.
By attaching the heat exchanger panel 1 to the heat exchanger panel, the temperature difference between the upper and lower surfaces of the lower header tank 3 is reduced to about half that of the conventional case without the heat receiving member 10 attached, and the life of the heat exchange panel 1 is extended by 4 to 5 times. be done.

In addition, from the lower surface of the place where the finch tubes are installed on the inlet side of the lower header tank 3 upright, to the end cap side, a portion of both ends of the entire group of finch tubes (for example, a length equivalent to 15 of each end portion) is heated. By attaching the member 10, the thermal stress applied to the finch tube is reduced in linear proportion to the temperature difference, and the effect of attaching the heat receiving member is significant.

In addition to the plate-shaped heat receiving member 10 shown in FIG. 1, various shapes can be adopted as the heat receiving member.

The heat receiving member 11 shown in FIG. Heat-receiving members 12 arranged in a required number at regular intervals in the axial direction, and heat-receiving members 12 arranged in a required number at regular intervals in the axial direction with plate pieces similarly arranged in the radial direction, as shown in Fig. c. You can also set it to 13 here.

The heat receiving member 14 shown in Fig. d is a pipe material bent into a wave shape and attached to the lower surface of the lower header tank 3, and the heat receiving member 15 shown in Fig. e is a corrugated plate attached in the same manner.

Any of the heat receiving members 11 to 15 described above exhibits the same effects as the heat receiving member 10 of FIG. 1.

Effects of the invention The open rack type evaporator based on this invention is
By attaching a heat receiving member to at least one place on the lower surface of the lower header tank, the temperature difference between the upper and lower surfaces of the lower header tank is significantly reduced compared to the conventional case where no heat receiving member is attached. This phenomenon can be prevented, the accompanying thermal stress can be reduced, damage to the finless portion can be eliminated, and the life of the heat exchange panel can be dramatically extended.

In addition, although the structure is simple, it is highly effective in eliminating temperature differences between the upper and lower surfaces of the lower header tank, and has the advantage of being inexpensive and easy to install regardless of whether it is an existing or new installation.

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view of an open rack type evaporator according to this invention. FIG. 2 is a perspective explanatory view of a lower header tank section showing heat receiving members of various shapes according to this invention. In the figure, 1... Heat exchange panel, 2... Upper header tank, 3... Lower header tank, 4... Manifold, 10, 11, 12, 13, 14, 1
5...Heat receiving member.

Claims (1)

[Claim for Utility Model Registration] Finch tubes with one or more pairs of fins protruding in the diametrical direction are arranged in the fin direction to form a single panel, and header tanks are provided at the upper and lower ends of the panel to form a heat exchange panel. A plurality of heat exchange panels are arranged in parallel, and a manifold is provided for distributing and supplying liquefied gas to each heat exchange panel by orthogonally connecting the ends of each lower header tank, and a manifold is provided above each heat exchange panel. In an open rack type evaporator that evaporates the liquefied gas in the tube by causing seawater as a heat medium to flow down onto the heat exchange panel surface from a water sprinkler placed in the tube, a heat receiving member is installed at at least one location in the longitudinal direction of the bottom surface of each lower header tank. An open rack type evaporator characterized by the fact that it is attached.