JPS6231994Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a well-inserted preheater.

In this specification, a well-inserted preheater (hereinafter simply referred to as a heater) refers to a heater that is inserted into a well tube installed along the outer surface of a pipe to preheat the pipe.

Since this heater is used by being inserted into the well, it must be easy to insert it into the well tube, and it must be easy to pull out from the well tube. Sufficient flexibility is required because it can be laid not only in straight lines but also in complex routes.

Various improvements have been made for this purpose, but none have been sufficient.

The present invention has been made in consideration of the above, and an object of the present invention is to provide a heater having sufficient flexibility over the entire length of the heater.

The present invention will be explained below with reference to examples.

Figures 1a and 1b are a partial cross-sectional view and a side view of an embodiment of the present invention.

In Fig. 1, reference numeral 1 denotes the shape of the outer jacket of the heater, and the outer cover ₁ is formed into a cylindrical shape by closely winding Inconel The outer diameter of the coil is gradually reduced to form a spiral shape.

The core wire 2 is welded inside the tip of the outer sheath 1, and the core wire 2
The heating element 3 is covered with the heating element 3.

As shown in Fig. 1, the heating element 3 is made by winding a single linear heating element from one end, folding it back at the tip, and then reversing the winding direction and winding it between the first wound linear heating elements. Configure it to go back in the opposite direction.

To wind the heating element 3 in this manner, for example, as shown in FIG. 2, a coiling core 5 is fixed to the chuck 4, and a single linear heating element is folded around a protrusion 6 fixed to the coiling core 5. Then, the folding point is engaged with the protrusion 6 to form two linear heating elements 3.
are formed by winding them in parallel on the core metal 5 for coiling, and then stretched to a certain pitch.

According to the heater configured as described above, since the entire outer cover is formed in a coil shape, it is flexible all the way to the tip, and can be installed along piping laid along a complicated route. It is also fully compatible with insertion into a well tube, and insertion into a well tube is extremely easy.

Also, when pulling out from the well tube, use the core bar 2.
The heater can be easily pulled out from the well tube without stretching the outer sheath 1 beyond its elastic limit by pulling the other end.

Further, when the heater moves on the inner surface of the well tube, each wire of Inconel X forming the coil is rounded and slides smoothly on the inner surface of the well tube.

Furthermore, if the heater has a preheating temperature distribution in its length direction, this can be easily handled by adjusting the pitch of the heating element in accordance with the preheating temperature distribution.

Furthermore, the mechanical strength during insertion and withdrawal can be provided by the core metal 2, and the mechanical strength can also be maintained sufficiently.

In the above explanation, we have explained the case where the outer sheath 1 is made of Inconel Since the temperature of the heater is expected to exceed 400°C, we have explained the case using Inconel X wire.

However, the materials of the outer cover and the core metal may be appropriately selected depending on the preheating temperature.

As explained above, according to the present invention, the entire heater has flexibility and is extremely easy to insert into and pull out from the well tube, making it ideal for insertion into the well tube. It is.

[Brief explanation of the drawing]

Figures 1a and 1b are a partial sectional view and a side view of an embodiment of the present invention. FIG. 2 is an explanatory diagram of a method for manufacturing a heating body. 1: Outer cover, 2: Core metal, 3: Heating body.

Claims (1)

[Scope of utility model registration request] a coiled outer covering consisting of a part in which a metal wire is tightly wound and forms a cylindrical body, and a part in which a predetermined length of the tip is wound from the cylindrical body in order of decreasing outer diameter to form a spiral shape; Consisting of a core metal inserted into the outer sheath and having one end fixed to the tip of the outer sheath, and a heating element made by folding back one linear heating element and winding two wires in parallel and covering the core metal. A well-inserted preheater characterized by: