JPS62236556A - Profile cross-sectional tubular body for heat exchange - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a heat exchange tubular body suitable for a small multi-tubular heat exchanger used for artificial organs and the like.

[Conventional technology] As a device for transferring heat from a high-temperature fluid to a low-temperature fluid or vice versa, it is used not only in industrial scales but also in household air-conditioning equipment, medical equipment such as artificial lungs, etc. etc., are used in various fields. In particular, shell-and-tube heat exchangers are generally widely used because they have excellent heat transfer efficiency and are simple in structure.

As materials for heat transfer tubes in shell-and-tube heat exchangers, friendly metals, especially corrosion-resistant stainless steel, have been commonly used because of their excellent heat transfer efficiency.

Recently, there has been a demand for a compact heat exchanger that can be incorporated into artificial organs, etc., and it has become practical to use a relatively thin stainless steel tube with an outer diameter of about 1 to 3 meters. However, when the outer diameter is 1 to 3 m, it is difficult to obtain a sufficiently large heat transfer area per unit volume of the tubular body. It is necessary to increase the internal volume of the exchanger, and when used in a total oxygenator, etc., which uses the heat transfer area as its name, the amount of blood being carried out of the body becomes large and the burden on the patient becomes heavy. There is a problem.

In order to solve this kind of problem, we have filed a special application in 1986-
In 162947, it was discovered that by using a tubular body as a heat transfer tube with a specified outer diameter and wall thickness, the entire heat exchanger therein could be made significantly more compact, and furthermore, the functionality could be dramatically increased.几.

[Problems to be solved by the invention] However, if the tubular body is an M model combination and is thin enough to be made compact, the tubular body itself is likely to deform. In addition, the linear shape of the tubular body is disturbed and the dispersibility of the tubular bundle becomes poor, and since the cross section of the tubular body is a perfect circle, the five tubular bodies are in close contact with each other, making heat exchange with the fluid flowing outside uniform and efficient. This is not done well and there are problems with performance stability, etc.

Therefore, even in such a thin tubular body, there is a need for a tubular body for friendly heat exchange that is difficult to deform and has excellent uniform dispersibility so that the tubular bodies do not come into close contact with each other when forming a module.

Means for Solving the Problems] The object of the present invention is to provide a heat exchanger pipe that overcomes the above-mentioned disappointment. That is, the gist of the present invention is that it is made of a thermoplastic M-machine polymer compound that can be melt-formed, and that has an outer diameter of 100 to 1000 mm.
In the tubular body having μvnf, the tubular body has at least 1 M of longitudinally extending protrusions satisfying the following formulas (1) and (2) on the outer periphery of the tubular body. .

D, /D, = 1.15-2. OO(1)(Dl K
T n ) / DBπ) 1.14 (2)
However, DI is the circular diameter (μm) of the tubular body D! is the outer diameter of the tubular body excluding protrusions (μm) π is the circumference T is the width of the protrusion (μm) n is the number of protrusions The material of the tubular body of the present invention is a thermoplastic organic polymer compound that can be melt-formed. If so, there are no particular limitations, or if it is used for medical purposes, it is safe.

A material that can be ensured in terms of reliability and that can be easily formed into a tubular body by bath melting is preferred, such as polyethylene.

Polypropylene, poly4-methylpentene-1° polyethylene terephthalate, polyamide, polycarbonate, polymethyl methacrylate.

Polyvinylidene fluoride, polyoxymethylene.

Preferred examples include polyvaraphenylene sulfide.

The outer diameter of the tubular body used is in the range of 100 to 1000 μm, but if the outer diameter exceeds 1000 μm, the heat transfer area per unit volume becomes small, making it difficult to make the heat exchanger compact.

However, if the outer diameter of the tubular body is less than 100 μm, the diameter becomes small and the pressure loss of the fluid flowing inside the tubular body becomes too high, which poses a problem. From the point of view of obtaining efficient performance of the heat exchanger, the outer diameter is 200 mm.
It is more preferable that it is 800 micrometers.

As shown in the first example, the tubular body of the present invention has a projection extending in the longitudinal direction on the outer periphery, and its shape must satisfy the conditions of formulas (1) and (2) above. be.

That is, as shown in Fig. 1, when the diameter of the circle in the cross section of the tubular body is kDt and the outer diameter excluding the protrusion is kDz, the film thickness is defined by the comparison of the circle diameter and the outer diameter /Dt. However, in the tubular body of the present invention, as shown in formula (1), D
2/DI is preferably in the range of 1.15 or more and 2.00 or less. If the thickness is 1.15%, the film thickness will be very thin, so it may not be good in terms of heat transfer efficiency, but its mechanical strength will drop significantly, and flattening or rupture will occur due to external or internal pressure during use, making it virtually impossible to use. It becomes impossible. Also, Dz/D
When I is greater than 2.00, the film thickness increases, heat transfer resistance increases, and heat transfer efficiency decreases significantly.

Furthermore, as shown in equation (2), the length 'rnt-i of the contact with the protrusion from the outer circumference D2π is the inner circumference length D
It needs to be larger than 1.14 times 1π. If this value is less than 1.14, the area occupied by the protrusions on the outer surface of the tubular body becomes large, leading to a significant reduction in the effective surface area of the tubular body, making the tubular body unsuitable for use as a heat exchanger.

Note that, as shown in FIG. 2, @T of the protrusion is represented by the length of the broken line portion where the outer circumferential surface and the protrusion are in contact. Although the number n of protrusions having a width T must be at least 1, it is preferably 1 to 8 in view of the dispersibility of the tubular body and the effective surface area. There are no particular restrictions on the height or shape of the protrusions, but if the protrusions are low, it is difficult to obtain effective dispersion, so it is preferable that the height is equal to or greater than the protrusion width. As for the entire method of manufacturing the replacement tubular body with irregular cross section, for example, the protrusion shape t! It is obtained by extrusion molding a thermoplastic M-machine polymer compound using a spinneret for hollow fibers with irregular cross-sections.

When using the irregular cross-section tubular body of the present invention as a heat transfer tube of a multi-tubular heat exchanger, the tubular body may have any filling rate, and if the filling rate is low, the bulk of the tubular body The uniform dispersibility of the tubular body bundle is the same as above. In addition, if the filling rate is high, it becomes difficult for the tubular bodies to stick together,
Rounding allows liquid to easily flow into the tubular bundle, enabling uniform and efficient heat exchange.

Examples Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Density [1968t/cry? , high-density polyethylene with a melt index of Mr. 5 (manufactured by Mitsui Petrochemical Co., Ltd.,
Hi-Zex 2208.7 )'i Double pipe structure with a discharge port size of 28mm and an annular slit width of 55mm! Then, there are 6 holes evenly spaced around the outer circumference! Using a spinneret for forming irregularly shaped hollow fibers, air was introduced in a self-priming manner, and the spinning temperature was set to 17.
Melt spinning was carried out at 0° C. and a discharge rate of 30 r/min, and winding was performed at a winding speed of 400 m/min.

The obtained polyethylene irregular cross-section tubular body had an outer diameter of 471 μm excluding the protrusion 1, a film thickness of 71 μm, and a width of one protrusion 2) p
m, height 28 pm %D2/DI = 1.43
, (D π - T n )/DI π = 1.51. 2256 of these polyethylene irregularly shaped tubular bodies are bundled and stored in a cylindrical container with a diameter of 45 cm and a length of 160 cm, and both ends are fixed with urethane resin with a thickness of 15 cm each to form a cylinder with an effective length of 130 cm. A total of 10 heat exchangers were manufactured.

The housed irregularly shaped tubular body has excellent fc bulkiness,
It was not observed in the areas where the tubular bodies were in close contact with each other. Further, when the end face of the heat exchanger was cut with a cutter and the cut surface was observed under magnification, it was found that the dispersion state of the tubular bodies was good.

Hema! is applied to the outside of the tubular body using the heat exchanger described above. :,
ocrtt (fi 35% cow 1IIL liquid is completely poured inside with water to perform heat exchange. As a result, the water flow rate IQ
z/mtn, blood 7PL bit t6 L/mi
n T, the heat exchange efficiency E shown below when the blood input side temperature is 30℃ and the water input side temperature is 40℃, as shown in Table 1, there is little fluctuation in each heat exchanger and excellent performance stability. It was confirmed that

K = (TBO-TBr) / (TWI-TBU)
Here, E: heat exchange efficiency, TBx: blood entrance temperature.

'rBo: Blood inlet temperature; Twz: Water inlet temperature and pressure.

Comparative example 1 The diameter of the circle is the same as in Example 1 except that the protrusion is not shaped like a poem.

A total of 10 cylindrical heat exchangers with an effective length of 130 m were fabricated using 2256 polyethylene tubular bodies having a full film thickness, and heat exchange was performed under the same conditions as in Example 1. The results are shown in Table 1. The heat exchange efficiency of the obtained heat exchangers varies widely from one heat exchanger to another.

Example 2 Melt index value at 230°C is 101F/10
A double pipe structure with a discharge port diameter of 25 mm and an annular slit width of 1.7 am! Using a spinneret for forming irregularly shaped hollow fibers having three protrusions at equal intervals on the outer periphery, air was introduced in a self-priming manner, and the spinning temperature was 200.
C. Spit! 10f/min, winding speed 6.00m/m
The polypropylene typical tubular body obtained had five protrusions at equal intervals, the outer diameter excluding the protrusions was 246 mm, and the film thickness was 22 μm.
The width of one protrusion is 9 μm, the height is 15 pm, Dz
/D%=t 22 , (Dz f Tn)/D,
Atsutomo with lm=1-18.

By bundling the polypropylene irregularly shaped tubular bodies 8843 together, a 1° cylindrical heat exchanger similar to that of Example 1 was manufactured. The stored bundle of tubular bodies showed good uniform dispersion, and no areas where the tubular bodies were in close contact with each other were observed.

Using the above heat exchanger, the heat exchange efficiency was investigated in the same manner as in Example 1, and the values shown in Table 1 were obtained, indicating that a heat exchanger with little variation in performance was obtained. Comparative Example 2 Same diameter as Example 2 except that the protrusion was not shaped like a poem.

Film thickness e! A group of 10 cylindrical heat exchangers with an effective length of 130M were made by bundling 8845 polypropylene tubular bodies. Then, the total heat exchange efficiency was investigated in the same manner as in Example 1, and the values shown in Table 1 were obtained. Because it is provided with protrusions, it not only has rigidity and excellent shape retention, but also has uniform dispersion because the tubular bodies do not stick to each other when modularized.

It has excellent bulk and a tubular shape.

Therefore, even in a compact secondary heat exchanger, it is possible to uniformly and efficiently exchange heat with the fluid flowing outside, which has a very large effect in terms of performance stability.

Simple explanation of old drawings In the figure Dl: V: J diameter Riku: Outer diameter excluding protrusions T: Width of protrusion shows.

River・1 diagram Temple map 2 Koji map 3

Claims (1)

[Claims] Made from a melt-formable thermoplastic organic polymer compound with an outer diameter of 1
A tubular body for heat exchange with an irregular cross section having a diameter of 00 to 1000 μm, the tubular body having at least one projection extending in the longitudinal direction that satisfies the following formulas (1) and (2) on the outer periphery of the tubular body. D_2/D_1=1.15~2.00(1)(D_2π
-Tn)/D_1π>1.14 (2) Where: D_1 is the circular diameter of the tubular body (μm) D_2 is the outer diameter of the tubular body excluding the protrusion (μm) π is the circumference τ is the width of the protrusion (μm) n is the number of protrusions