JPH0648795Y2 - Electric heater for boiler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement of a sheathed heater type electric heater which is used in an electric boiler or the like and heats boiler water.

(Prior Art) Generally, a sheathed heater type electric heater is used for an electric boiler, and heats boiler water by this.

By the way, the impurities contained in the boiler water adhere to the surface of the heat generating portion of the electric heater as time passes. As a result, there has been a problem that the output is reduced due to the heat insulation effect of the scale, or the electric heater is damaged due to overheating.

Thus, conventionally, when the scale is attached to the electric heater,
This is generally removed by chemical cleaning,
These chemical cleaning methods include various methods such as inorganic acid cleaning using hydrochloric acid or sulfuric acid as a main component, organic acid cleaning using citric acid or hydroxyacetic acid, and the like.

(Problems to be solved by the device) However, since chemical inhibitors use corrosion inhibitors in all cases, waste liquid treatment is required and chemicals are used, which causes various problems in terms of safety and hygiene. Will occur.

The present invention was created in order to solve the above problems, and an object thereof is to provide an electric heater for a boiler capable of removing the scale generated in the heating portion of the electric heater without chemical treatment. That is.

(Means for Solving the Problems) The present invention is a plurality of metal thin plates having good heat conductivity formed by bending in a cylindrical shape on the outer surface of a metal cylinder forming a heat generating portion of an electric heater for a boiler. It is a basic constitution of the invention that the cylindrical metal-coated body is inserted in a line, and is elastically attached to the outer surface of the metal-made cylindrical body by the elastic force of the cylindrical metal-coated body so as to be detachably and closely attached. It is a thing.

(Function) On the outer surface of the heat generating portion of the electric heater, a cylindrical metal coating made of a thin metal plate is inserted in a line, and the heat generating portion of the heater is completely covered with the metal coating. .

Further, the electric heater is detachably attached to the boiler barrel in a state where the heat generating portion is immersed in boiler water, and heats the boiler water by energization.

When the scale begins to adhere to the metal coating of the electric heater with the passage of operating time of the electric boiler, it is taken out from the boiler before the heat transfer from the electric heater to the boiler water begins to deteriorate, and the metal coating Remove the scale with it by removing it from the heating element.

Since the scale is removed in this manner, there is no need to use a chemical for removing the scale, and the scale removing operation can be performed safely and hygienically. In addition, since the electric heater is taken out of the boiler to remove the scale, no scale remains in the boiler and the scale can be easily and easily disposed.

In the electric heater from which the scale has been removed, a new metal coating is again attached and fixed to the heat generating portion, and then attached to the boiler.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a front view of an electric heater 1 according to a first embodiment of the present invention, in which the electric heater 1 has a metal tubular body forming a heat generating portion 2 on the surface of which is a thin metal having good thermal conductivity. A plurality of cylindrical metal coverings 5 made of plates are detachably inserted.

Specifically, a rod-shaped sheathed heater is used as the electric heater 1, and a flange 3 for mounting the heater is provided at one end of the metal cylinder forming the heat generating portion 2, and An electrical terminal 4 is provided on the flange 3 in a protruding manner.

The metal cover 5 is formed in a tubular shape by bending a thin metal plate having good thermal conductivity (for example, a stainless steel plate or a copper alloy plate) into a cylindrical shape, and a plurality of the tubular metal cover 5 are attached to the outer surface of the heat generating portion 2 in a line.

It should be noted that, as shown in FIGS. 2 and 3, both ends of each metal cover 5 are ear pieces used when the metal cover 5 is inserted into the heat generating part 2 or is separated from the heat generating part 2. 5a is formed and firmly and removably adhered and fixed to the outer surface of the heat generating portion 2 by the elastic force of the metal cover 5 itself.

FIG. 4 is a schematic vertical sectional view of an electric boiler using the electric heater 1. The electric heater 1 is detachably attached to the boiler barrel 7 in a state where the heat generating portion 2 to which the metal cover 5 is fixed is immersed in the boiler water 6.

That is, in the electric heater 1, the heat generating portion 2 is inserted into the boiler cylinder 7 through an opening formed in the upper part of the boiler cylinder 7, and the heater mounting flange 3 and the flange 8 formed on the boiler cylinder 7 are attached to bolts, nuts, etc. By fixing with the tightening tool 9
It is detachably attached to the boiler barrel 7.

In FIG. 4, 10 is a water supply pump, 11 is a water supply pipe, and 12 is a water supply pipe.
Is a water level controller, 13 is a steam outlet, 13 is a drain pipe, and 15 is a drain valve.

If the scale adheres to the outer surface of the metal coating 5 of the electric heater 1 due to the running time of the electric boiler, the operator removes the scale from the boiler barrel 7 before the influence of overheating on the electric heater 1 begins, and the scale is removed. The metal coating 5 to which is attached is mechanically removed, and the scale is removed together therewith.

After removing the scales in this way, a new metal coating 5 is inserted into the heat generating portion 2 and closely fixed to the outer surface of the heat generating portion 2, and then the electric heater 1 is attached to the boiler cylinder 7
Attach to.

When replacing the metal cover 5, only the metal cover 5 to which the scale is attached may be replaced, whereby the consumption of the metal cover 5 can be reduced.

Thus, when removing scale, the electric heater 1
Need only be taken out of the boiler cylinder 7 and the metal coating 5 is removed. Therefore, compared to scale removal work using chemicals, the work can be performed safely and sanitarily, and the peeled scale remains in the boiler cylinder 7. Of course, it is easy and easy to dispose of the scale.

Further, the shape of the metal cover 5 is not limited to that of the above-mentioned embodiment, and may be any shape as long as it can be attached to and detached from the heat generating portion 2 in a close contact state.

In the above-described embodiment, the electric heater 1 is provided with the flange 3, and the flange 3 and the flange 8 of the boiler cylinder 7 are fixed by the tightening tool 9. However, the structure for attaching the electric heater 1 to the boiler cylinder 7 is The structure is not limited to the above-mentioned embodiment, and may have any structure.

Further, in the above embodiment, the electric heater 1 is inserted into the boiler cylinder 7 from above, but the electric heater 1 may be inserted into the boiler cylinder 7 from below.

Further, the electric heater 1 may be used in a once-through type boiler, and the heater 1 may be inserted into the water pipe or the header of the once-through type boiler.

(Effects of the Invention) As described above, in the electric heater of the present invention, a plurality of thin metal plate-shaped tubular metal coverings 5 are detachably and closely attached to the heating portion of the electric heater. The scale is attached to the outer surface of the.

As a result, by removing the electric heater from the boiler and removing the metal cover 5, the scale can be completely removed together with it, and the scale removing operation can be performed safely and hygienically.

Further, since the scale can be removed by taking out the electric heater from the outside of the boiler, no scale remains in the boiler, the inside of the boiler does not need to be frequently cleaned, and the scale can be easily and easily disposed.

Furthermore, since the outer surface of the heat generating portion is protected by the metal cover 5, the scale is never directly fixed to the heat generating portion, and the service life of the electric heater is extended.

In addition, when the electric heater is easily attached to and detached from the boiler, the scale removal work can be performed relatively easily and easily, so the raw water may be supplied as it is without using a softening device. . In this case, equipment such as a softening device is unnecessary, and cost reduction can be achieved.

Also, use an electric heater for corrosion resistant steel materials (eg stainless steel)
When the use of the deoxidizing agent, the cleansing agent, etc. is stopped by using it in the boiler, safe and hygienic steam or hot water can be obtained.

[Brief description of drawings]

FIG. 1 is a front view of an electric heater according to an embodiment of the present invention,
FIG. 2 is a perspective view of a metal coating used for an electric heater, FIG. 3 is a side view of the same metal coating, and FIG. 4 is a schematic vertical sectional view of an electric boiler using the electric heater of the present invention. 1 is an electric heater, 2 is a heat generating part, and 5 is a metal coating.

Claims (1)

[Scope of utility model registration request] 1. A sheathed heater type electric heater for a boiler, wherein a metal thin plate having good heat conductivity is curved into a cylindrical shape on the outer surface of a metal tubular body forming a heat generating portion 2 of the boiler electric heater. A plurality of tubular metal-coated bodies 5 formed at most were inserted in a line, and the elastic force of the tubular metal-coated bodies 5 removably and closely attached to the outer surface of the metal-made tubular body. An electric heater for a boiler, which is characterized in that