JPH0345801A - Electric once-through boiler - Google Patents

Abstract

PURPOSE:To increase the output power of a boiler by inserting a coil-shaped electric heater into a plurality of water tubes which are connected between upper and lower headers. CONSTITUTION:Headers 2 and 3 are closed at their both ends and are arranged horizontally. Both ends of each of a plurality of water tubes 4 are connected to the lower section of the upper header 2 and to the upper section of the lower header 3, and they are provided vertically. An coil shaped electric heaters 5 are inserted into respective water tubes 4 from the upper section of the upper header 2. When the electric heaters 5 are energized, the water in the lower header 3 and the water tubes 4 is heated, and steam is generated from the upper section of the water tube 4. The steam is sent to a steam and water separator 11 through the upper header 2 from the upper sections of the water tubes 4, and after it is separated into steam and water, the steam is sent to a steam load through a steam valve 12. At this time the electric heaters 5 can make large their electric capacity per unit volume because of the coil shape, and it is, therefore, possible to increase the output of boiler.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in an electric once-through steam boiler that heats water to generate steam.

(Prior Art) Conventionally, as this type of electric once-through steam boiler, for example, Japanese Utility Model Publication No. 57-190201 and Japanese Utility Model Publication No. 62-26645 are known.
Those listed in the number are known.

This basically consists of upper and lower headers, a plurality of water pipes connected between them, and a U-shaped electric heater inserted into the water pipes from the top of the upper header.

However, since such a device uses a U-shaped electric heater, the electric capacity per unit volume cannot be increased.

For this reason, there was a drawback that the boiler output could not be increased.

(Problems to be Solved by the Invention) The present invention was devised to solve the above problems, and its purpose is to provide an electric once-through steam boiler that can increase the boiler output.

(Means for Solving the Problems) The electric once-through steam boiler of the present invention basically consists of upper and lower headers, a plurality of water pipes connected between them, and a coil-shaped electric heater inserted into the water pipes. It is distinctive in that it is composed of and.

(Function) When the electric heater is energized, the water in the water pipe is heated and steam is generated.

At this time, since the electric heater has a coil shape, the electric capacity per unit volume of the water pipe can be increased.

Therefore, the boiler output can be increased.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a partially cutaway front view showing an electric once-through steam boiler according to an embodiment of the present invention. FIG. 2 is an enlarged front view of the main parts of the electric heater. FIG. 3 is an enlarged cross-sectional plan view of the main parts of the electric heater.

The main parts of the electric once-through steam boiler 1 include headers 2 and 3, water pipes 4, and an electric heater 5.

The headers 2.3 are upper and lower, and in this example are cylindrical, closed at both ends, and arranged horizontally.

The water pipes 4 are a plurality of water pipes connected between the upper and lower headers 2 and 3, and in this example, have a cylindrical shape, both ends are connected to the lower part of the upper header 2 and the upper part of the rudder 3, and are arranged vertically. Three of them are provided at predetermined intervals in the horizontal direction.

The water pipe 4 has an inner diameter of 50 m.

At the top of the upper header 2, a mounting pipe 6 is provided to extend to each ice tube 4, and a lid 7 is removably provided at the top to close the pipe.

The electric heater 5 is a coil-shaped heater inserted into the water tube 4 . In this example, the base is attached through the lid 7 and inserted into the water tube 4 from the upper part of the so-called upper header 2 .

The electric heater 5 is made up of a heating wire 8, an insulator 9 covering it, and a sheath 10 covering it, and is flexible, and has a power supply (not shown) at both ends of the heating wire 8. ) is connected.

The electric heater 5 has a coil outer diameter of 40 mm, a coil length of 500 m+, a coil winding number of 83 turns, a gap between the coils of 1.2 m, a heating wire 8 outer diameter of 1 glue, and a length of the heating wire 8. Saga 9
174m, the resistance of the heating wire 8 is 14.30, the outer diameter of the sheath 10 is 4.8cm, the length of the sheath 10 is 9174cm, the surface area of the sheath 10 is 1383cJ, the voltage is 400v, the output is 11189W, the power density is It is 8W/-.

A steam/water separator 11 is connected to the upper header 2, and a steam valve 12 and a safety valve 13 are connected to this. steam valve 1
2 is connected to a steam load (not shown).

A water supply pump 14 that supplies water into the lower header 3 and the water pipes 4 is connected to the lower header 3 .

A water level controller 15 is provided between the upper ladder 2 and the lower header 3 to control the water supply pump 14 to maintain the water level at a predetermined value.

Next, the operation will be explained based on such a configuration.

When the electric heater 5 is energized, the water in the lower header 3 and the water pipe 4 is heated, and steam is generated from the upper part of the water pipe 4.

The generated steam is sent from the upper part of the water pipe 4 to the steam/water separator 11 via the upper header 2, and after being separated from steam and water, it is passed through the steam valve 1.
2 to the steam load.

At this time, since the electric heater 5 has a fill shape,
The electric capacity per unit volume can be increased.

Therefore, the boiler output can be increased.

Although the upper and lower headers 2 and 3 and the water pipe 4 were fixed together in the previous embodiment, they are not limited to this, and may be used, for example, in the second embodiment shown in FIG. As in the third embodiment and the fourth embodiment shown in FIGS. 8 to 10, they may be connected in a detachable manner.

In this way, when performing maintenance and inspection of the water pipe 4 and the electric heater 5, it becomes possible to remove the water pipe 4 and the electric heater 5 at the same time, and maintenance and inspection can be easily performed.

Although the upper and lower headers 2.3 and the water pipes 4 were fixed together in the previous embodiment, the present invention is not limited to this. For example, as in the fourth embodiment shown in FIGS. 8 to 10, each water pipe 4 may be separated. It may also be connected in a detachable manner.

In this way, a steam boiler with the required capacity can be easily manufactured, making it ideal for producing a wide variety of products in small quantities.

In the previous embodiment, the electric heater 5 was inserted into the water pipe 4 from the upper part of the upper header 2, but the electric heater 5 is not limited to this, and can be inserted, for example, in the second embodiment shown in FIG. 4 or the sixth embodiment shown in FIG. 13. Like,
It can be inserted into the ice tube 4 from the bottom of the lower header 3, or inserted from the bottom of the water tube 4 as in the third embodiment shown in FIGS. 5 to 7 and the fourth embodiment shown in FIGS. 8 to 10. It may also be inserted into the water pipe 4.

In this way, it is possible to prevent the electric heater 5 from being exposed to the steam portion and being damaged by overheating.

Further, since the electric heater 5 has a coil shape, it is flexible and the downward dimension H required for insertion can be reduced.

Although the electric heater 5 had a constant power density in the vertical direction in the previous embodiment, the power density is not limited to this, and may be changed as in the fifth embodiment shown in FIGS. 11 and 12, for example. good.

In other words, in this example, the electric heater 5 is divided into three parts, upper, middle, and lower, and the heating wire 8 is divided so that the voltage, resistance, and output of these parts are the same.
The outer diameter of the coil is made small, medium and large from the top, and the coil pitch is made small, medium and large from the top, so that the power density becomes small, medium and large from the top.

In this way, the power density is low in the steam section above the ice tube 4, and the power density is high in the high temperature water section below the water tube 4, so water can be heated efficiently, and the electric heater 5 Miniaturization and long life can be achieved.

Although nothing was provided inside the electric heater 5 in the previous embodiment, the present invention is not limited to this, and a core material 16 may be inserted, for example, as in the embodiment shown in FIG.

That is, in this example, it has a cylindrical shape with a closed lower part, an air hole 17 that opens to the outside air in the upper part, and a base part that passes through the upper header 2 and is fixed thereto.

In this way, it is possible to support the flexible coil-shaped electric heater 5, and the amount of water in the water pipe 4 is reduced, thereby shortening the startup time (effects of the invention). According to the invention, the following excellent effects can be achieved.

(1) It is composed of a header, a water pipe, and an electric heater, and especially since the electric heater is coil-shaped, the electric capacity per unit volume can be increased, and therefore the boiler output can be increased.

(2) Since the electric heater is simply made into a coil, the structure is not complicated and the cost is not too high.

(3) Just make the electric heater into a coil shape. Therefore, it can be easily applied to existing systems.

If the upper and lower headers and water pipes are removably connected, maintenance and inspection of the water pipes and electric heaters becomes easier.

(5) If the upper and lower headers and wood pipes are separated for each water pipe and removably connected, a steam boiler with the required capacity can be easily manufactured.

When the electric heater is inserted into the water pipe from the lower part of the lower header, damage to the electric heater from overheating can be prevented, and the downward dimension required for insertion can be reduced.

(7) When the power density of the electric heater is changed in the vertical direction, water can be heated efficiently, and the electric heater can be made smaller and have a longer life.

(8) When a core material is inserted into the electric heater, the electric heater can be supported and the startup time can be shortened.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing an electric once-through steam boiler according to an embodiment of the present invention. (4) (6) FIG. 2 is an enlarged front view of the main parts of the electric heater. FIG. 3 is an enlarged cross-sectional plan view of the main parts of the electric heater. FIG. 4 is a front view showing the second embodiment. FIG. 5 is a plan view showing the third embodiment. FIG. 6 is a partially cutaway front view of FIG. 5. Figure 7, a side view of Figure 5. FIG. 8 is a plan view showing the fourth embodiment. FIG. 9 is a partially cutaway front view of FIG. 8. FIG. 10 is a side view of FIG. 8. FIG. 11 is a schematic front view of an electric heater showing a fifth embodiment. FIG. 12 is a wiring diagram of the electric heater shown in FIG. 11. FIG. 13 is a longitudinal sectional front view of the main part showing the sixth embodiment. ......Electric once-through steam boiler...Top header...Bottom header...Water pipe...Electric heater Figure 2 Figure 1 3 doctors, Figure 4, Figure 5, Figure 4, Figure 6, Figure 77.

Claims (1)

[Claims] 1. An electric once-through steam boiler comprising upper and lower headers, a plurality of water pipes connected between them, and a coil-shaped electric heater inserted into the water pipes. 2. The electric once-through steam boiler according to claim 1, wherein the upper and lower headers and the water pipes are removably connected. 3. Claim 1 in which the upper and lower headers and water pipes are separated and removably connected to each water pipe.
Electric once-through steam boiler as described. 4. The electric once-through steam boiler according to claim 1, wherein the electric heater is inserted into the water pipe from the lower part of the lower header. 5. The electric once-through steam boiler according to claim 1, wherein the electric heater has different power density in the vertical direction. 6. The electric once-through steam boiler according to claim 1, wherein a core material is inserted into the electric heater.