JPS61101797A - Heat conductive plate of plate type heat exchanger - Google Patents

Abstract

PURPOSE:To provide a low-cost, corrosion-resistant and reliable heat conducting plate by forming respective passage holes with a corrosion-resistant ring fastened to the base material, and coating an enamel layer on the entire front and back surfaces of the base material. CONSTITUTION:A certain soft steel plate is press-stamped. At this time, a gasket fitting groove and heat conductive part 3 are formed, and a ring attaching hole 9 is punched. A corrosion-resistant ring 10 is inserted into the ring attaching hole 9, and is fixed by welding. Then, the front and back surfaces near to the corrosion-resistant ring 10 are sand-blasted, and, as preliminary treatments, degreasing, acid cleaning and nickel plating are performed. Therefore, an enamel coating is applied. That is, after spraying enamel solvent, a heat treatment is applied at 850 deg.C for 5min. In order to eliminate defects such as pinholes, the spraying and heat treatment are repeated two times. Then, after performing inspections with pinhole tester etc. and necessary repair, a teflon gasket 2 is fitted in the gasket fitting groove, which completes all the processes.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a heat transfer section that has a heat transfer section forming a circulation passage on the front side R, and a heat transfer section that penetrates in the direction of the front side and communicates with a passageway on the L side. The present invention relates to a heat transfer plate for a plate heat exchanger having through holes.

(Prior Art) Fig. 5 shows a conventional heat transfer plate for a plate exchanger, and this heat transfer plate has circulation holes 1 at the four corners of the square shaped plate. A heat transfer portion 3 surrounded by a casket 2 is formed on the surface other than the surface Av. This heat transfer plate has the same shape as seen from the front side in FIG. 5, that is, when viewed from the front side, the back side has the opposite shape to the front side.

As shown in FIG. 6, a plurality of these heat transfer plates are stacked one on top of the other to form two passages.

This refitting method includes, for example, one end plate 6 having a hot fluid outlet 114 and a cold fluid outlet 8;
For example, the heat transfer plate shown in FIG.
On the second plate, the heat transfer brake I and the concave plate shown in Fig. 5 are assembled by rotating the plate 1801 times in one plane using the method shown in Fig. 5. In this order j'f-, the heat transfer plates are alternately folded together and sandwiched between one of the two side plates 6, 6 to form a flow passage between the opposing conductive portions 3, 3. In this case, C Nishikojiji is 614th, with the flow of 1 population H, the temperature is 11i, and the soul of arrow C is the low temperature fluid. configured to be traced.

For example, IAi, I
01 with high risk of corrosion due to sulfuric acid etc. as ID fluid
Therefore, conventionally, the heat transfer plate has been made of a 1-4" curved lumber such as stainless steel, nickel alloy steel, or titanium alloy steel, which has excellent corrosion resistance.

However, the use of such materials does not meet the goals of corrosion resistance and is quite expensive as a heat transfer plate.

In view of this, in order to provide an inexpensive heat transfer plate, the present applicant attempted to use a mild steel plate as the heat transfer plate itself and coat the entire front and back of the mild steel plate with enamel to ensure corrosion resistance.

However, with the conventional heat transfer plate, as shown in Figure US7, an enlarged cross-sectional view of the vicinity of the LTC through hole l.
In order to ensure that all parts including the inner peripheral edge of the west through hole 1 are made of mild steel, if this mild steel plate is coated with enamel, the straight hole marked in white on either the through hole 1 or the heat transfer plate 11 will be removed. If this is the case, the boundary between the plate surface and the Jk through hole l will be in a shape that is straight (11). Although such a shape is cheap to manufacture, there is a problem in the following gap.

In other words, if the above-mentioned angular parts exist, even if the enamel is coated, the enamel layer will be attached to the inner peripheral surface of the flow hole 1 (the surface of the mild steel base material will remain exposed). be.

If the enamel layer 11 is difficult to adhere to the flow hole 1 in this way, when a fluid with corrosive properties such as sulfuric acid is passed through for heat exchange, the enamel layer 11 will not be present and the flow hole will have an exposed surface. This is not preferable because corrosion begins through the through hole 1.

Therefore, for example, it is recommended not to make the angular part have a radius of 3R or more, or to coat the part from the angular part to the flow hole 1 with another corrosion-resistant layer so as to be continuous with the enamel layer 11. is possible, but
In this way.

There is another problem with reliability, as the coating layer on the inner circumference of JQ '11 hole 1 tends to peel off.

(Object of the invention) This invention was made in view of the above problems, and
The purpose is to provide a (7,76 plate) that is low cost and highly reliable in terms of corrosion resistance.

(Structure of the invention) In order to achieve the object described in h.
Formed by a corrosion-resistant ring fixed to the base material and (
The entire front and back of the material is coated with an enamel layer.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

The overall configuration in Fig. 1 is the same as the conventional structure shown in Fig. iS6, so the heat transfer plates, in which the same reference numerals are given and explanations are replaced, are as shown in Fig. 2, one of which is taken out. Then, ring mounting holes 9 as shown in Fig. 3 are formed at four corners, and a corrosion-resistant ring 10 made of stainless steel is inserted and welded into the inner IN of the ring mounting hole 9, and the inner circumference of this corrosion-resistant lick 10 is A circulation hole 1 is formed in the portion.

While the corrosion-resistant ring 10 is made of stainless steel,
The material of the heat transfer plate is made of mild steel for enamel.

As shown in FIG. 3, the entire front and back surfaces of the heat transfer plate including the corrosion-resistant ring IO are coated with the enamel layer 11, and a method for manufacturing the same will be explained with reference to FIG.

In the fourth flash, first, in step S1, a predetermined mild steel plate is attached to the casket fitting rIv1 (not shown) and the heat transfer part 3 (
(Fig. 2) is press-formed, and at this time, ri/gu removal (
One hole 9 (FIG. 3) is punched out at the same time.

In step S2, as shown in FIG. 3, the corrosion-resistant ring 1o is inserted into the hole 9 and fixed by welding.

In step S3, in order to increase the adhesion of the enamel layer l to the front and back surfaces around 1° of the corrosion-resistant ring of the third [Δ], and to make the treatment in step S4 more effective, blasting is performed. .

In step S4, degreasing, washing, and thin nickel plating are performed as 1111 processing.

In step S5, the enamel is subjected to neaty puffer treatment, that is, after spraying the enamel solvent, 8
Heat-treat at about 50'C for 5 minutes.

Here, to eliminate defects such as pinholes.
- Repeat the above spraying and heat treatment twice.

Next, in step S6, inspection by pinhole test and necessary repairs are carried out, and after HLT, a Teflon gasket 2 (Fig. 2) is fitted into the groove for attaching the gasket to complete the entire process. .

The heat transfer plate manufactured in this way can use a mild steel plate as its base material, so it cannot be sealed in a conventional method using expensive materials such as stainless steel, nickel alloy steel, or titanium alloy steel. , it becomes very inexpensive in terms of cost.

On the other hand, as shown in Figure A3, the enamel qtt is applied to the entire front and back of the heat transfer plate, and the enamel layer 11 is formed even on the front and back of the corrosion-resistant ring 1O. However, the inner peripheral wall of the flow hole 1 itself is a corrosion-resistant stainless steel surface as in the above embodiment, so the flow fluid may not be as corrosive as sulfuric acid. Even so, it is tolerable.

Note that the heat transfer section 3 may be of a type in which uneven grooves are formed.

(Effects of the Invention) As explained above, according to the present invention, each circulation hole is formed by a corrosion-resistant ring that is attached to the base material, and the entire front and back of the base material is coated with a enamel layer.
A heat transfer plate with high reliability in terms of corrosion resistance can be provided at low cost.

[Brief explanation of the drawing]

1 IN is an exploded perspective view of a plate exchanger showing an embodiment of the present invention, FIG. 2 is a front view showing the heat transfer plate taken out, and FIG. 3 is a knee m line in FIG. U°〃
Figure 4 is an enlarged cross-sectional view of the heat transfer plate.
Fig. 5 is a front view showing a conventional heat transfer plate. Fig. 6 is an exploded perspective view of a plate type heat transfer plate having a conventional heat transfer plate. Fig. 7 is a main part along the line ■-vII in Fig. 5. It is an enlarged sectional view. DESCRIPTION OF SYMBOLS 1... Distribution hole, 3... Heat transfer part, 10... Corrosion-resistant ring. 4th stage 51st

Claims (1)

[Claims] (1) In a heat transfer plate for a plate heat exchanger, which has a heat transfer part forming a circulation passage on the front and back sides, and has a circulation hole penetrating in the front and back direction and communicating with the heat transfer part, each of the circulation passages as described above is provided. A heat transfer plate for a plate heat exchanger, characterized in that the holes are formed by corrosion-resistant rings fixed to a base material, and the entire front and back of the base material is coated with an enamel layer.