JP2700324B2 - Repair method for lining of pipe inner surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an existing pipe for gas laid underground.
The present invention relates to a method for repairing a lining of a pipe inner surface in which a uniform resin lining is applied to the pipe inner surface in a laid state.

[Conventional technology]

In general, existing pipes for gas laid underground are subject to aging, so that corrosion holes and joints may always be loosened and leaked. At the required time, the existing pipe is repaired by resin lining on the inner surface of the pipe in the laid state.

Therefore, as described in JP-A-63-65983, the inside of the existing pipe is filled with a liquid resin group so as to fill and close the inside of the pipe, and the resin group is filled with a predetermined low-pressure gas. A lining repair method for the inner surface of the pipe was proposed, in which the inner surface of the pipe was lined with a required thickness. Here, a launcher is connected to one end of the open existing pipe, and a resin tank is filled from a resin tank connected to the launcher to form a resin group in the launcher, and this is supplied from the free end of the launcher. The low-pressure gas (for example, low-pressure air) is supplied into the existing piping. Then, the resin group flows under the pressure of the low-pressure gas in the existing pipe to perform lining of the pipe inner surface. If on the way, due to the lining above,
When the resin is exhausted, the resin is again filled into the launcher from the resin tank, a resin group is formed in the launcher, and the resin group is fed into the existing pipe with low-pressure gas. The work is repeated in this manner to repair the inner surface of the existing pipe for a predetermined length.

[Problems to be solved by the invention]

The problem here is that most of the existing piping to be repaired is currently in use, so there is a severe restriction on the construction time. Normally, in this kind of repair work, there is a time constraint of about eight hours from the stop of the gas supply to the restoration. However, during this time,
Preparations such as excavation of the road surface at both ends of the repair section, cutting of the exposed part of the existing pipe, removal of the meter of the supply pipe, and gas purging are indispensable. Since post-processing is necessary, the working time for the inner surface repair is as short as about 2 hours. A particular problem is that when the lining resin is uncured during recovery, when gas is passed through, the resin flows from the loose gap or the corroded hole of the screw joint due to the pressure,
There is a problem that the lining film is broken. For this reason, the pot life is further reduced in consideration of the time for curing the resin. Also, depending on the situation, the entire construction time must be extended, which inconveniences the user.

The present invention has been made based on the above circumstances, and in consideration of the composition of the resin used for the lining, the pressure of the gas used in the existing piping does not cause a flow even in an uncured state. Therefore, it is an object of the present invention to provide a method for repairing a lining of a pipe inner surface in which a waiting time for resin curing is omitted and a working time is substantially extended.

[Means for solving the problem]

Therefore, in order to solve the above problems, the present invention
Filling the existing pipe with a plug-shaped liquid resin group, supplying the required low-pressure gas from one side of the resin group, and moving the resin group to form a lining of a required thickness on the inner surface of the pipe. In the surface lining repair method, the flowability of the resin used for the resin group is increased by the low-pressure gas supplied during repair, but is reduced by the gas pressure used in the repaired pipeline after restoration. It is characterized by a thixotropic value of such an extent that it does not.

[Action]

Therefore, by considering the composition of the resin used for the lining so that fluidity does not occur even in the uncured state at the gas pressure used in the repaired existing piping, there is no waiting time for resin curing. Thus, the working time can be extended.

〔Example〕

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

In the figure, reference symbol A indicates an existing pipe to be repaired. The existing pipe A is intended for a gas branch pipe having a diameter of about 50 to 80 mm or a gas main pipe having a diameter larger than that.

At the time of repair, the existing pipe A is divided into repair sections of a predetermined length and both ends are opened. For this reason, the bearings B and C are excavated at locations corresponding to both ends. And
The launcher 1 is connected to the existing pipe A opened by means such as cutting through a connection port body 2 with a clamp.
Further, with respect to the service pipe D connected to the existing pipe A, the meters are removed and the ground end is opened. Then, pressurized air is passed through the existing pipe A and the service pipe D to remove dust and the like inside.

Further, a resin injector 3 as a resin supply means is connected to the launcher 1 via an electrode opening / closing valve 4, and a liquid is supplied from the resin injector 3 so as to fill and close the existing pipe A over a predetermined length. Is introduced into the launcher 1 in a required amount.

The lining resin E is a room-temperature two-pack curing resin prepared by mixing a main agent and a curing agent, and the main agent is an unsaturated polyester resin, a vinyl ester resin, an epoxy resin,
A composition containing a urethane resin or the like as a main component, to which a pigment, a thixotropic agent, and the like are added, for example, 250,000 to 300,000
The composition has a high viscosity and a high thixotropic property, such as a viscosity of cps and a thixotropy value (TI) of 6. For example,
An example of the composition of the composition when the lining resin E is mainly composed of an epoxy resin is as follows.

(Blend) (parts by weight) (% by weight) Epoxy resin 100 76.9 Scaly filler 15 11.5 Pigment 5 3.8 Thixotropic agent 4 3.1 Other additives 6 4.6 The scaly filler may be, for example, aluminum, silver, clay or the like. , Mica, molybdenum diversion, talc,
Glass, graphite, etc. are used as raw materials and are formed in a scale shape. For example, the thickness is 1 to 5 μm, and the diameter is 0.5 to 3 mm.
Fine powders and granules generally used are merely used as bulking agents, and have very little blocking effect on pressure. The flakes are arranged in such a way that the flakes are superimposed on the gaps or pits, and they are entangled with the resin, as if they were covered. Moreover, the thixotropic agent used here is added in order to secure the above-mentioned thixotropic property.

In addition, the resin in which the main agent and the curing agent are mixed in advance may be pressure-fed and supplied to the resin injector 3 by an air pressurized injection device, or while the main agent and the curing agent are pressure-fed by separate pumps, In the process, both may be mixed and supplied by a static mixer.

The launcher 1 is provided with an electromagnetic on-off valve 5, and is connected to a low-pressure gas supply device 7 controlled by a control unit 6. The low-pressure gas supply device 7 includes a compressor 8, an air tank 9, flow control valves 10, 11, flow meters 12, 13, and pressure gauges 14, 15, particularly
In this embodiment, a three-way switching valve 16 is provided at the outlet side of the compressor 8 to supply compressed air to the resin injector 3, and pressurized air is supplied to the resin injector 3 via a pipe 17. It has become. A flow regulating valve 18 is provided in the pipe 17 and is controlled by the control unit 6. Control unit 6
Calculates from the flow meters 12, 13 and pressure gauges 14, 15 and a control program to adjust the opening of the flow control valves 10, 11, and also controls the opening and closing of the electromagnetic on-off valves 4, 5.

Therefore, by the control unit 6,
When the electromagnetic on-off valve 4 is closed and the electromagnetic on-off valve 5 is opened and the low-pressure gas is directed to the existing pipe A via the launcher 1, the resin group flows by the pressing force of the low-pressure gas,
It is sent while lining the required thickness on the inner surface of the existing pipe A.

In this case, the calculation basis in the control unit 6 depends on the following formula.

First, the amount of low-pressure gas flowing into the existing pipe A (diameter D)
Assuming that Q ₁ and pressure P ₁ (for example, 0.6 kg / cm ² ), there is a relationship of π / 4 · D ² · l ₁ · P ₁ = Q ₁ · P _O. By measuring Q ₁ , P _O , and P ₁ at the time T _{1 at which} the feeding of the resin group starts, l _{1 is obtained} from the equation (1).
You can know. Here, obtained by difference between the measured values F _1, F ₂ of the flow meter 12, 13 of the amount to Q ₁ gas that has flowed into the existing pipe A. In this case, if a mass flow meter is used for the flow meters 12 and 13, there is no influence of the gas temperature, so that the calculation is easy. Also, here, l ₁ is the position of the resin group at time T ₁ ,
P _O and P ₁ are the measured values of the pressure gauges 14 and 15, and D is the lining inside diameter of the existing pipe A.

Similarly, if the pressure P ₂ and the inflow amount Q ₂ at the time T ₂ are measured, and the position of the resin group obtained by calculation is l ₂ ,
The flow velocity V of the resin group is V = Δl / Δt.

Here, Δl = l ₂ −l ₁ Δt = T ₂ −T ₁ .

Therefore, the predetermined time interval Δt is set by the clock of the oscillator in the control unit 6, and each time, the flow meter
The flow rate adjusting valves 10 and 11 are measured so that the resin flow velocity V at each instant is maintained at a constant predetermined value by measuring the amount of inflow gas flowing into the pipes from the pipes 12 and 13 and the pressure gauges 14 and 15.
Is controlled.

In the existing pipe A, the length of the resin group decreases because it is consumed for lining to the inner surface of the pipe, but since the flow velocity is constant, the pressure of the pressurized gas drops substantially linearly (third pipe).
See figure).

If the resin of the resin group is consumed before the resin lining on the inner surface of the existing pipe A is completed over the entire length of the pipe, the resin group length becomes gradually shorter, and at the same time, the pressure gas for maintaining the resin flow velocity constant is reduced. The pressure also decreases substantially linearly, and when the resin group length becomes zero, the pressure of the pressurized gas naturally becomes the atmospheric pressure.

The gas inflow Q up to this time, the length l to the position where the resin lining is completed, the elapsed time t _{O, and the} like are stored in the memory, and the electromagnetic on-off valve 5 is closed. On the other hand, the control unit 6 detects that the pressure has been reduced to the atmospheric pressure, opens the electromagnetic on-off valves 4 and 18, supplies and fills the lining resin into the launcher 1 from the resin injector 3, To form Then, the electromagnetic on / off valves 4 and 18 are closed, the electromagnetic on / off valve 5 is opened, and the existing pipe A is lined while controlling the speed V of the resin group again as before.

At this time, while the lining resin group moves at a predetermined speed V in the previously lined pipe, the film thickness of the lining in the pipe does not change, so that the length of the resin group does not decrease, and the pressure of the pressurized gas is reduced. Is also maintained at a substantially constant value.

However, after the resin group reaches a position where the pipe A has not yet been lined, the resin is consumed by the lining, and the length of the resin group is reduced. Therefore, the lining is performed while the pressure of the pressurized gas gradually decreases. The progress is the same as described above. In this case, the resin leader becomes substantially 0, the pressure of the pressure gas is atmospheric pressure again, the elapsed time up to this time is approximately 2t _O next, also the length of the end position of the lining is substantially 2l.

In this way, the lining length is successively extended while repeating the lining by filling and pressing the resin.

When the lining of the existing pipe A is completed and the resin group reaches the receiver 19 connected to the connection with the main pipe or the opposite end of the existing pipe A with the length of the resin group still remaining, the resin group moves out of the existing pipe A. Since the resin flows out and the flow resistance of the resin group in the pipe A sharply decreases, the pressing force controlled by the control unit 6 also sharply decreases to reach atmospheric pressure. In addition, the elapsed time until the pressing force is reduced to the atmospheric pressure is also set to (n × t).
(N-1) t + t '(where t'<t) (see FIG. 3).

That is, it is determined that the resin group has reached the outside of the existing pipe A from the sudden decrease in the pressing force and the difference between the elapsed time and the estimated elapsed time, and the lining repair for the existing pipe A is completed.

In this way, it can be determined that the repair lining of the pipe A has been completed. However, if the resin is injected again and the lining is performed by the pressurized gas, the time required to reach the branch pipe is the same as the previous time (n-1). ) T + t ′. In this way, each repair lining time is the same,
The arrival of the resin group at the existing pipe A terminal can also be determined.

In the drawing, reference numeral 20 denotes a receiver tank that receives the residual resin discharged to the reservoir 19 at the end of the resin lining.

In addition, in the service pipe D branched from the existing pipe A, this is previously lining with resin, and then it is preferable to take appropriate resin intrusion prevention measures in preparation for the lining of the existing pipe A. . In addition, the pipe inner surface lining repair method of the present invention can be applied to the above-mentioned internal pipe.

When the lining repair is completed in this manner, the meter is immediately attached to the service pipe D in the repair section, the pipe connection at the open end of the existing pipe A, the purge, the ignition test, etc. are performed, and the excavated portion is backfilled. And restore. In this recovery section, the lining resin is a temporally uncured be used gas is supplied here, the gas pressure is generally a 0.025 kg / cm ² degree, very low, whereby the On the other hand, since the resin having the high viscosity and the high thixotropic value does not flow, there is no possibility that the lining film is broken.

〔The invention's effect〕

The present invention has been described in detail above, in consideration of the composition of the resin used for the lining, at the pressure of the gas used in the existing piping, so as not to flow even in an uncured state. Therefore, the waiting time for curing the resin can be omitted, and the working time can be substantially extended. In addition, it is possible to shorten the entire construction time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a repair method showing one embodiment of the present invention, FIG. 2 is a configuration diagram for supply and control of low-pressure gas, and FIG. 3 is a time chart showing a repetition state of resin lining. It is. DESCRIPTION OF SYMBOLS 1 ... Launcher, 2 ... Connection body, 3 ... Resin injector, 4, 5 ... Electromagnetic on-off valve, 6 ... Control unit, 7 ... Low-pressure gas supply device.

Claims (1)

(57) [Claims] 1. An existing pipe is filled with a liquid resin group in the form of a plug, and a required low-pressure gas is supplied from one side of the resin group to move the resin group. In the lining repair method for the inner surface of the pipe that performs lining, the flowability of the resin used for the resin group is reduced by the low-pressure gas supplied during repair, but is used in the repaired pipeline after restoration. A lining repair method for the inner surface of a pipe, which has a thixotropic value that does not flow at a low gas pressure.