JPH07125085A - Hot air heating device for synthetic resin tube - Google Patents

Abstract

PURPOSE:To heat a synthetic resin tube by hot air smoothly even under the working environment of strong wind in order to prevent the cracks to be formed by low temperature fragility of a synthetic resin tube when the synthetic resin tube is laid underground by excavating the underground. CONSTITUTION:A flexible hose 2 is connected with an outlet of a hot air generator 1 having a heater 12 and a fan 11, and a pad 3 being brought into contact through a hot air flowing clearance is installed at the end of the flexible hose 2 on a face to be heated, a temperature sensor 5 is installed on the inner face side of the pad 3, and a control section 15 for controlling the fan 11 by means of the output of the sensor 5 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot air heating device used for heating a synthetic resin pipe to prevent its cold brittle cracking.

[0002]

2. Description of the Related Art In water and sewage, it is often necessary to connect a branch pipe to an existing main pipe in order to expand the sewerage system along with the construction of residential land. In this case, the main pipe is made of vinyl chloride resin. In the case of a synthetic resin pipe such as a pipe, a predetermined portion of the main pipe is perforated by a perforator (Horso), and a branch pipe is connected to this hole for communication.

However, when this perforation work must be performed at low temperatures in winter or at night (around 5 ° C. below freezing), the main pipe is cracked by the load during perforation due to the low temperature brittleness of the synthetic resin pipe. It is known that the main pipe is heated and pierced in order to eliminate such a risk, because there is a fear that it will occur (for example, when the blade is chipped or rusted, cracking is likely to occur). ing.

Conventionally, when the synthetic resin pipe buried in the ground is punched by excavating the underground, the synthetic resin pipe is heated and softened to remove the residual strain on the pipe wall and then punched. Therefore, it is known to heat a synthetic resin pipe with an electrothermal contact type heating jig (Japanese Patent Publication No. 3-56352).

Therefore, in order to remove the residual strain of the synthetic resin pipe product, it is necessary to heat the synthetic resin pipe product at a temperature about 5 ° C. lower than the heat distortion temperature of the synthetic resin for 1 to 2 hours.
An electrothermal contact type heating jig is suitable for heating for a long time.

[0006]

However, in order to prevent low-temperature brittle cracking of the above synthetic resin pipe, for example, a vinyl chloride resin pipe, it is sufficient to heat the synthetic resin pipe to 20 to 30 ° C., and to heat it with hot air. Is enough. In the above electric heating heater contact type heating jig, it is necessary to use the electric heating body provided with the insulating coating in close contact with the surface to be heated with a sufficient tightening pressure, and when the number of times of use increases, it is necessary to repeatedly tighten. , The insulation coating layer is easily fatigued, making it difficult to maintain insulation of the electric heating heater,
Since there is a risk of electric leakage, 20-30 of the synthetic resin pipe
From the viewpoint of security, it is advantageous to use the hot air heating method for heating at about ℃. Of course, unlike the burner method, the hot air heating method is safe without any risk of charring or melting of the constituent resin pipes, and is also advantageous in this respect.

However, when the work site is windy,
The normal hot air heating method has the disadvantages that the hot air is agitated by the wind and it is difficult to perform work smoothly, and the workability depends on the wind conditions.

An object of the present invention is to add a synthetic resin pipe with hot air in order to prevent cold brittle cracking of the synthetic resin pipe when the synthetic resin pipe buried in the ground is punched by excavating the underground. It is an object of the present invention to provide a hot-air warming device for a synthetic resin pipe, which is capable of smoothly heating even in a windy working environment.

[0009]

SUMMARY OF THE INVENTION A hot air heater for a synthetic resin pipe according to the present invention has a flexible hose connected to the outlet of a hot air generator having a heater and a fan, and a heated surface is attached to the heated surface. A pad is attached to the tip of the flexible hose through the hot air flow gap, a temperature sensor is provided on the inner surface of the pad, and the output of the sensor controls the fan. The configuration is characterized in that a section is provided.

[0010]

The hot air generated by the hot air generator passes through the flexible hose and passes through the hot air flow gap between the pad and the surface to be heated,
Furthermore, while the hot air is exhausted from the edge of the pad and the hot air passes through the hot air flow gap between the pad and the surface to be heated, the hot air contacts the surface to be heated and the surface to be heated is heated. It gets warm.
Therefore, even if a strong wind is blowing at the site, the hot air will not be agitated by the wind before it flows out of the pad. Further, since the temperature sensor is provided on the inner surface side of the pad, even if the wind blows, the temperature detected by the temperature sensor, and thus the output of the temperature sensor, hardly changes, and the wind of the control system does not change. Hunting due to can be sufficiently prevented.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing an embodiment of the present invention.

In FIG. 1, reference numeral 1 is a hot air generator operated by an AC power source (100 V or 200 V), a fan 11, an electric heater 12 arranged at the inlet or outlet of the fan 11, and a heating temperature. (Reference value) setting resistor 13, switch 14 of fan 11, controller 15 for performing on / off control of fan 11 by comparing the output of the temperature sensor on the surface to be heated and the reference value, set temperature, and A temperature display unit 16 for displaying the detected temperature, a timer 17, etc. are provided.

Reference numeral 2 denotes a flexible hose connected to the hot air outlet of the hot air generator 1, such as a soft plastic hose or a core material such as an iron coil coated with a synthetic resin liquid-coated non-woven fabric. Can be used. Reference numeral 3 denotes a semi-cylindrical pad attached to the tip of the flexible hose 2, which can use a flexible rubber sheet or a plastic sheet, and is a synthetic resin pipe P which is a heated surface.
In order to make contact with the outer surface of the sheet through the hot air flow gap a, spacers 31, ... Are provided on the rear surface (this spacer may be integrally formed with the pad, The spacers may be fixed to the pad with an adhesive), and the spacers other than the spacers at the outermost ends of these spacers are provided with hot air circulation slots 32.

In FIG. 1, reference numeral 4 denotes a band for retaining the pad 3 on the heated synthetic resin pipe portion. It is also possible to omit this band and fix the pad to the synthetic resin pipe by binding with wire or string.

Reference numeral 5 denotes a temperature sensor attached to the inner surface of the pad (which may be either a contact type or a non-contact type).
An electric wire 21 embedded in the pipe wall of the flexible hose 2 is connected to the control unit 15 described above.

In the hot air heating apparatus of the present invention, when a hole is bored in a synthetic resin sewer main line buried in the ground by means of a Horso or the like and a branch pipe is connected in communication with this hole, the portion to be bored is heated. However, it is used to prevent low temperature brittle cracking of the synthetic resin pipe during perforation, and FIG. 3 shows its use state.

In FIG. 3, P indicates a synthetic resin sewer main buried in the ground, which excavates the earth and sand around the portion to be perforated,
The part to be perforated is exposed. Reference numeral A denotes a hot air heating device of the present invention, in which the pad 3 is applied to the perforated portion of the synthetic resin pipe P, and the pad 3 is fixed to the synthetic resin pipe P by tightening the band 4.

After fixing the pad 3 to the synthetic resin pipe P,
Set the heating temperature setting resistance of the hot air generator to a predetermined value, set the heating time to a predetermined time with a timer, switch on the power supply, generate hot air, and generate this hot air with a flexible hose. It is passed through the heating flow gap between the pad 3 and the synthetic resin pipe P via 2 and then discharged from both ends of the pad 3.

In this case, the temperature of the heated portion is detected by the temperature sensor-5, the fan is continuously driven until the detected temperature reaches the set temperature, and the temperature of the heated portion is set to the set temperature. After that, the set temperature is maintained by the on / off control of the fan by the output of the temperature sensor, and the heating by the set temperature is maintained during the set time by the timer.
Done.

In the above, the preset temperature for heating is a temperature required to prevent low-temperature brittle cracking of the synthetic resin pipe due to the load of the punch, and is usually in the range of 20 to 30 ° C.
The set time is the time required to heat the entire wall thickness of the perforated portion of the synthetic resin pipe to the above temperature, and is usually several tens of minutes.

In the above, the hot air leaving the hot air generator is
Since the flexible hose and the pad block the outside from the both ends of the pad until the air is exhausted to the outside, the hot air can be prevented from being blown even if the wind in the workplace is strong. Further, even if the wind condition changes frequently in the workplace, there is almost no change in the temperature detected by the temperature sensor, and it is possible to prevent the control system from hunting due to wind disturbance.

[0022]

The hot air heating device for the synthetic resin pipe of the present invention is
With the configuration as described above, it is possible to prevent the blowing condition of the hot air and the control system of the hot air generator from being affected by the wind in the workplace. Therefore, even if the synthetic resin pipe is heated by the hot air, it depends on the working environment. You can warm up smoothly without having to. Further, since hot air is used as the heating medium, unlike burning by the burner, it is possible to reliably avoid the burning of the synthetic resin tube.

Therefore, according to the heating of the present invention, the perforated portion of the existing synthetic resin main sewer pipe is heated to about 20 to 30 ° C., and the portion is subjected to low temperature brittle cracking by means of a Horso or the like. Can be safely drilled.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a pad in the embodiment of FIG.

FIG. 3 is an explanatory view showing a usage state of the hot air heating device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hot air generator 11 Fan 12 Heater 15 Control part 2 Flexible hose 3 Pad 5 Temperature sensor-P Synthetic resin pipe

Claims (1)

[Claims] 1. A flexible hose is connected to an outlet of a hot air generator having a heater and a fan, and a pad which is brought into contact with a surface to be heated via a hot air flow gap is used as the flexible hose. -A hot air warming device for a synthetic resin pipe, characterized in that it is attached to the tip of the pad, a temperature sensor is provided on the inner surface side of the pad, and a control unit for controlling the fan with the output of the sensor is provided. .