JPH0894175A - Heating element for liquid - Google Patents

Abstract

PURPOSE: To provide a heating element for liquid, which is suitable for heating liquid efficiently and, especially, the heating element for liquid, which is capable of securing the property of safety for heating dialyzate and capable of efficient heating. CONSTITUTION: A heating element 1 for liquid is provided with a rod type heap generating body 2, having a metallic armor, a metallic cylindrical receiving vessel 3, receiving the rod type heat generating body 2 therein concentrically and equipped with pipeline connecting units 6, 7 for the inflow and the outflow of liquid, and a metallic flow passage partition 5, inserted into a gap 4 between the armor of the rod type heat generating body 2 and the inner wall of the receiving vessel 3 and fixed spirally so as to be contacted with the armor and the inner wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating element for efficiently heating a liquid, particularly for heating a liquid in the medical field, and particularly for heating a dialysate to an appropriate temperature in hemodialysis treatment. Regarding the temperature element.

[0002]

2. Description of the Related Art Conventionally, when heating a liquid continuously, an apparatus for heating the liquid while circulating the liquid in a pipe is generally used. The same applies to the heating of the dialysate, in which a stainless steel pipe through which the dialysate flows is formed in a spiral shape, and the heating element arranged at the center of the spiral pipe and the stainless steel pipe are integrally cast with aluminum. A heating device is used.

Since this heating device is integrally cast from aluminum between the heating element and the stainless steel pipe through which the dialysate flows, it is excellent in heat conduction and is particularly efficient in heating the dialysate. There is an advantage that heating is easy. However, if minute cracks or holes occur in the stainless steel pipe due to deterioration due to long-term use or defects in the manufacturing process, the dialysate leaks out and comes into contact with aluminum, so aluminum ions are mixed in the dialysate and Since it is not easy to detect a trace amount of aluminum ions, there is a risk of causing a serious clinical accident.

Although the above-mentioned heating device is excellent in heat conduction, the dialysate and the heating element are separated by aluminum and stainless steel pipes and are not in direct contact with each other. Moreover, since the piping has a circular cross section, the cross-sectional area of the flow path of the dialysate becomes larger than other cross-sectional shapes,
It is not yet satisfactory in terms of efficient heating and temperature control of dialysate.

[0005]

SUMMARY OF THE INVENTION In view of such conventional circumstances, the present invention provides a liquid heating element suitable for efficient heating of liquid, and is particularly safe for heating dialysate. It is an object of the present invention to provide a heating element for a liquid that can secure the above-mentioned temperature and can perform efficient heating.

[0006]

In order to achieve the above object, a liquid heating element provided by the present invention comprises a rod-shaped heating element having a metal exterior, and a rod-shaped heating element which is concentrically housed therein. A metal cylindrical storage container provided with a pipe connection for inflow and outflow of liquid, and a spiral insertion in contact with the outer wall and the inner wall in the gap between the outer wall of the rod-shaped heating element and the inner wall of the storage container. It is characterized in that it is provided with a metal flow path partition attached.

[0007]

In the liquid heating element 1 of the present invention, as shown in FIG. 1, a rod-shaped heating element 2 having a metallic exterior is concentrically arranged and housed in a metallic cylindrical container 3. Therefore, a cylindrical clearance portion 4 is formed between the exterior of the rod-shaped heating element 2 and the inner wall of the storage container 3 which are concentrically arranged. The storage container 3 is provided with a liquid inflow pipe connection portion 6 and a liquid outflow pipe connection portion 7 at both ends.

In addition, in the gap portion 4 between the rod-shaped heating element 2 and the storage container 3, a metal flow path partition wall 5 is provided in a state of being in contact with both the inner wall of the storage container 3 and the exterior of the rod-shaped heating element 2. It is spirally inserted at a winding pitch P. Therefore, the gap 4 between the rod-shaped heating element 2 and the storage container 3 is partitioned by the flow path partition wall 5, and a spiral liquid channel is formed around the rod-shaped heating element 2. The sectional shape of the channel partition wall 5 is not particularly limited,
For example, the cross-sectional shape may be triangular, quadrangular, circular, or the like. Further, the flow path partition wall 5 can be formed by spirally cutting the outer wall surface of the exterior of the rod-shaped heating element 2.

When a liquid to be heated such as dialysate is supplied to the heating element 1 from the inflow pipe connecting portion 6, it linearly flows out through the gap portion 4 between the rod-shaped heating element 2 and the storage container 3. Rather than flowing toward the pipe connection portion 7 for use, the spiral gap portion 4 partitioned by the spiral flow path partition wall 5, that is, the spiral liquid flow path is drawn to the outflow pipe connection portion 7 while drawing a spiral. It flows toward and is heated by the rod-shaped heating element 2 during this time.

Therefore, according to the heating element 1 of the present invention, the liquid to be heated flows spirally around the metal heating element 2 of the rod-shaped heating element 2, so that the liquid to be heated is heated by the rod-shaped heating element 2. Since the distance to be heated in contact with is long and the cross-sectional area of the spiral liquid flow path can be reduced, efficient heating can be performed.

Further, since the cross-sectional area of the spiral liquid flow passage is small, the liquid to be heated flows uniformly over the entire surface of the rod-shaped heating element 2 at almost the same flow rate, so that the temperature of the rod-shaped heating element 2 is partially increased. Therefore, it is possible to prevent the generation of bubbles in the liquid to be heated and to extend the life of the rod-shaped heating element 2 itself.

When the spiral flow path partition wall 5 is not provided,
The liquid to be heated is the gap 4 between the rod-shaped heating element 2 and the storage container 3.
Does not flow uniformly, and a flow occurs in a specific portion of the gap 4.
As a result, there is a fatal defect that the efficiency of heat exchange is reduced, and the flow rate is slow in the portion where the flow rate is small, the temperature rises greatly, and bubbles are easily generated.

The winding pitch P of the flow path partition wall 5 and the interval of the gap 4 between the rod-shaped heating element 2 and the storage container 3 are appropriately selected depending on the kind and flow rate of the liquid to be heated. For example, when the flow rate of the liquid to be heated is small, the winding pitch P of the flow path partition wall 5 is made small, and the liquid to be heated and the rod-shaped heating element 2 are brought into close contact with each other to improve heat exchange efficiency. Is preferred.

In particular, if the winding pitch P of the flow path partition 5 spirally inserted is made longer than the gap of the gap 4 between the inner wall of the container 3 and the exterior of the rod-shaped heating element 1, the rod-shaped heating element 2 is formed. Since the cross-sectional area of the liquid flow path can be reduced at the same time while increasing the contact area with, it is effective for efficient heating and rapid and appropriate temperature control.

Further, when the dialysate is used for heating, the material of the portion in contact with the dialysate, that is, the exterior of the rod-shaped heating element 2, the inner wall of the storage container 3, the flow path partition wall 5, etc., is made of stainless steel. It is preferable. As a result, there is no danger of aluminum being mixed in the dialysate as in the conventional case, and safety can be ensured.

FIG. 2 shows a specific example of a heating device incorporating the heating element 1. The liquid in the mixing tank 12 is sent to the heating element 1 by the liquid sending pump 13 and circulated in the mixing tank 12 via the liquid temperature detector 14. Specifically, the valve 16 is opened to introduce the liquid into the mixing tank 12, and the liquid feed pump 13 continuously supplies the liquid in the mixing tank 12 to the heating element 1 through the valve 17. Heating element 1
The liquid heated in step 3 passes through the liquid temperature detector 14 and the mixing tank 12
Circulate back to.

The circulation and heating of the liquid are repeated until the liquid temperature of the liquid detected by the liquid temperature detector 14 reaches a predetermined set value, and when the predetermined temperature reaches the predetermined set value, the controller 15 causes the heating element 1 to operate. The power supply to the rod-shaped heating element 2 is stopped. afterwards,
The valve 17 is closed and the valve 18 is opened, and the heated liquid in the mixing tank 12 is supplied to another device.

[0018]

EXAMPLE One specific example of the heating element of the present invention will be described with reference to FIG. The heating element 1 is used for heating the dialysate, and the rod-shaped heating element 2 is AC100V, 1k.
A resistance heating element of W, the outer periphery of which is covered with an outer casing of a stainless steel bottomed cylindrical body. On the other hand, the storage container 3 is a cylindrical body made of stainless steel, and the bottom part thereof is sealed by a bottom plate 8 made of stainless steel. Further, the storage container 3 has a liquid inflow pipe connecting portion 6 at one end and a liquid outflow pipe connecting portion 7 at the other end.

The rod-shaped heating element 2 is inserted into the storage container 3, and the upper flange portion 9 of the rod-shaped heating element 2 and the upper flange portion 10 of the storage container 3 are hermetically fixed to each other, so that the rod-shaped heating element 2 is heated. 2 and the storage container 3 are concentrically arranged and fixed. In addition, 11 is a heating element electrode of the rod-shaped heating element 2.

In the gap 4 between the concentrically arranged rod-shaped heating element 2 and the storage container 3, coils made of stainless steel and having a circular cross section are respectively in contact with the exterior of the rod-shaped heating element 2 and the inner wall of the storage container 3. In this state, the flow path partition wall 5 is formed by being spirally inserted. The distance of the gap portion 4, that is, the distance between the exterior of the rod-shaped heating element 2 and the inner wall of the storage container 3 is 4 mm, and the flow path partition wall 5 made of a coil inserted spirally is wound 5 times at a winding pitch P of 37 mm. Has been done.

Using this heating element 1, an actual heating test of tap water was carried out. That is, the inflow pipe connecting portion 6
From the tap water at a flow rate of 4.0 liter / min and 10 liter / min, the temperature of the tap water flowing out from the outflow pipe connecting portion 7 is detected by the liquid temperature detector, and the flange of the rod-shaped heating element 2 is detected. The temperature of part 9 was also measured. For reference, the same heating test was performed using the same comparative heating element as the heating element 1 except that the spiral flow path partition wall 5 was not provided. The obtained results are shown in Table 1.

[0022]

[Table 1] (Note) The value in parentheses in the table is the time required to reach the indicated liquid temperature and flange temperature after temperature equilibration of the heating element. The tap water temperature was 25.8 ° C ± 0.15 ° C.

From this result, in the heating element having no flow path partition, the flow of the liquid is not uniform, so that there is a portion where the heat of the heating element is not heat-exchanged with the liquid, and the temperature rise of the flange portion becomes large. It can be seen that, in the heating element having the flow path partition of the present invention, heat exchange is uniformly performed, the temperature difference between the liquid temperature and the flange portion temperature is small, and efficient heating is possible.

[0024]

According to the present invention, a heating element for liquid suitable for efficient heating of the liquid is provided by bringing the liquid to be heated into contact with the exterior of the heating element and reducing the flow passage cross-sectional area. can do. Moreover, since the heat of the heating element is uniformly exchanged with heat on the entire surface of the heating element, a partial temperature rise of the heating element is prevented,
It is possible to prevent the generation of bubbles of the liquid to be heated and to extend the life of the heating element.

In particular, if the portion that comes into contact with the liquid to be heated is made of stainless steel, there is no danger of aluminum contamination as in the prior art, and a safe and efficient dialysate heating element can be provided.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing a specific example of a liquid heating element of the present invention.

FIG. 2 is an explanatory diagram of a liquid heating device incorporating the liquid heating element of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating element 2 Rod-shaped heating element 3 Storage container 4 Gap 5 Flow path partition 6 Inflow piping connection 7 Outflow piping connection 8 Bottom plate 9, 10 Flange 11 Heating element electrode 12 Mixing tank 13 Liquid feed pump 14 Liquid Temperature detector 15 Control unit 16, 17, 18 valves

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Suzuki Hiroshi Suzuki 613 Kitairizo, Sayama-shi, Saitama Prefecture Toa Denpa Kogyo Co., Ltd. Sayama Plant (72) Yuhiro Zurima 613 Kitairi, Sayama-shi, Saitama Prefecture Toa Radio Koyama Co., Ltd.

Claims (2)

[Claims] 1. A rod-shaped heating element having a metal exterior, a rod-shaped heating element concentrically housed therein, and a cylindrical container made of metal provided with a pipe connecting portion for inflow and outflow of liquid, and a rod-shaped container. A heating element for liquid, comprising: a metallic flow path partition which is spirally inserted in contact with the exterior and the inner wall in a gap between the exterior of the heating element and the inner wall of the storage container. 2. The heating element for liquid according to claim 1, wherein the material of all parts contacting with the liquid is any one of stainless steel, ceramics and heat resistant resin.