JPH045599Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a low-pressure automatic control device used when backfilling mortar/cement paste (hereinafter simply referred to as paste).

[Technical background] In repair work for tunnels, etc., so-called back-filling mortar injection method is used, but this method deforms or damages aged rolled concrete due to the pressure of mortar injection. There is a major premise that this should not happen.

High-pressure automatic control devices for mortar and cement paste injection in dam grouting have been developed in the past, but since the set pressure for backfilling mortar injection is as low as 3Kg/ ^cm2 , pressure increases and changes are difficult. often occurs rapidly. This sudden pressure increase poses the risk of pushing out the rolled concrete from the back side and damaging it, and this needs to be avoided, but conventionally there has been no appropriate means to precisely control the set pressure range. , automation was delayed. However, as repair work for waterway tunnels and the like by backfilling has become more common these days, there is an urgent need to develop a low-pressure automatic control device.

[Prior Art] Conventionally, devices as shown in FIGS. 7 and 8 have been used as a means for controlling the backfill injection pressure of mortar, cement paste, etc.

In the apparatus shown in FIG. 7, a gland cox is placed in the middle of a paste supply pipe 1 to branch it into an injection side pipe 3 and a return pipe 4, and a pressure gauge 5 is attached to the injection side pipe 3. The paste is sent from the supply pipe 1 via the gland tank 2 to the injection side pipe 3 to the injection port 6, and the injection pressure is detected by the pressure gauge 5. An observer is monitoring this pressure gauge 5, and when the pressure exceeds the set pressure, the ground pressure gauge 2 is connected to the return pipe 4.
This method involves turning the paste to the side and returning the paste to the tank side. However, this method requires a supervisor to constantly monitor the pressure gauge.
Furthermore, if the pressure rises rapidly, the operation to open the gland pot 2 tends to be delayed, and there is a risk of injecting with excessive pressure. Further, in another conventional means shown in FIG.
A pressure regulating valve 14 is installed between the injection port 11 and the injection port 11. This valve 14 is adapted to adjust the pressing pressure of the piston valve 17 by the force of a spring 15, and this spring force is set by a bolt 16.

The valve 17 is designed to open and close the paste return port 13, and when the pressure exceeds the set pressure,
The valve 17 is pushed up against the spring 15,
The paste is automatically returned to the return port 13.

However, since the set pressure is as low as about 3 kg/cm ² , it is difficult to set the spring 15 to the set pressure, and errors in injection pressure are likely to occur. Consequently, there is a problem in that it becomes necessary to separately install a gland cock shown in FIG. 7 to monitor and control the pressure gauge 12 manually. Furthermore, since the valves are closed all at once, there is a problem in that the injection pressure drops excessively.

Furthermore, there is a problem in that it is not possible to cope with cases where the paste flows out due to the condition of the back side of the rolled concrete and the injection pressure suddenly decreases.

[Purpose of the invention] Therefore, an object of the present invention is to provide an apparatus that eliminates the above-mentioned conventional problems by accurately controlling the paste injection pressure and the upper and lower values even at a low set pressure.

[Configuration of the invention] The low-pressure automatic control device for mortar/cement injection according to the invention includes a control valve that communicates with a return port between a paste supply port and an injection port, a pressure sensor on the injection port side, and a pressure sensor for the injection port. Equipped with a control device that issues a valve open signal to the actuator of the control valve for a certain period of time set by a timer based on a signal from the sensor, and a switching valve that holds the actuator in the valve open state when there is no signal from the pressure sensor. There is.

[Operations and Effects of the Invention] Therefore, when the injection pressure reaches a set value during backfilling injection work, the control valve is opened for a certain period of time (for example, 2 seconds) set by the timer. As a result, some amount of paste flows into the return port and the injection pressure decreases. Since the injection operation continues, when enough paste has been injected, the injection pressure will rise again, and the control valve will open further for a certain period of time as before, resulting in an even larger return amount. As a result, the injection pressure is further reduced. In this way, as the amount of back-filling injection increases, the injection can be performed at progressively lower pressures.

If the low injection force continues, the control valve is held at its open position, allowing the injection operation to continue at that low pressure.

In the end, injection can be performed at a considerably low pressure, allowing for sufficient backfilling. In this way, the injection operation is continued while the control valve is held at a certain opening degree until the pressure rises to the set pressure, so the injection operation can be performed at a low pressure and sufficient backfilling operation can be performed. As a result, it is possible to eliminate the risk of damage to rolled concrete due to excessive injection pressure, or failure of repair work due to too low injection pressure, and the need for personnel to monitor injection pressure can be eliminated. It has the following effects.

[Preferred Embodiment] When implementing the present invention, the actuator is constituted by a hydraulic/pneumatic piston cylinder that opens a control valve using air pressure and closes the control valve using hydraulic pressure, and the control device is provided with a timer section. , it is preferable to open the valve in small lifts at a time. In this way, it is possible to accurately respond to minute changes in low injection pressure. Furthermore, when carrying out the present invention, it is preferable to provide a check valve to prevent flow toward the oil tank in a circuit that bypasses the flow rate regulating valve and orifice connecting the oil-pneumatic piston cylinder and the oil tank. In this way, it is possible to prevent the control valve from suddenly opening and to close the control valve quickly.

[Examples] Examples of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, the apparatus of the present invention includes a control panel 21 on a base 20, a paste control section generally indicated by 22, an air compressor 23 for driving the paste control section 22, an air tank 24, etc. There is. The control panel 21 is equipped with a control device (Fig. 4) 25, a pressure setting meter 26, a power switch 27, a power lamp 28, etc.
Further, on the side panel 29 of the device, an operating lamp 31 for a switch 30 for the air compressor and a control valve 32 to be described later is provided.

The paste control unit 22 includes a control valve 32, a cylinder 33 for driving the control valve, a mortar/cement paste supply port 34, an injection port 35, and a return port 3.
6. Injection pressure sensor 37 provided in the injection port 35
It consists of etc.

As shown in FIG. 3, the control valve 32 has an inlet 32a connected to the pipe 38 side connecting the supply port 34 and the injection port 35, and a valve chamber 32b connected to the return port 36 side. It is designed to lift from the fully closed position shown in the figure to the fully open position shown by the chain line. A valve rod 40 connected to the valve body 39
is a piston 41 of a hydraulic/pneumatic piston cylinder (hereinafter referred to as cylinder) 33 connected to a control valve 32
is connected to. As shown in FIG. 4, one working chamber A defined by the piston 41 of the cylinder 33 is selectively connected to the air tank 24 or the atmosphere by an air circuit L1 via a 4-port 3-position electromagnetic switching valve 42. It is becoming more and more common. Further, the other working chamber B of the cylinder 33 is connected to the oil tank 43 by an oil circuit L2, and the other working chamber B of the cylinder 33 is connected to an oil tank 43 by an oil circuit L2.
2 is provided with an electromagnetic on-off valve 44 and a flow rate adjustment valve 45, and a circuit L3 bypasses the flow rate adjustment valve 45.
A check valve 46 is provided to prevent oil from flowing toward the oil tank 43. and,
The air in the gap of the oil tank 43 is selectively connected to the air tank 24 or the atmosphere by an air circuit L4 via the electromagnetic switching valve 42.

On the other hand, the control device 25 has a control section 25a and a timer section 25b, and the control section 25a includes an electric circuit L5,
By L6 and L7. The pressure sensor 3 is connected to the pressure sensor 3 via the operating parts of the electromagnetic switching valve 42 and the electromagnetic on-off valve 44, the pressure setting meter 26, and the pressure amplifier 47, respectively.
7 is connected. Note that L8 indicated by a thick chain line is a mortar-cement circuit.

The pressure setting meter 26 is as shown in FIGS. 5 and 6, and has an upper limit pressure setting needle 50 and a lower limit pressure setting needle 51 on the display plate, and a pressure needle 52 that indicates the pressure. The pressure signal sent from the amplifier 47 is displayed. That is, the two setting needles 50 and 51 can be set to an arbitrary pressure by means such as a knob (not shown).

Next, the operation will be explained mainly with reference to FIG.

The mortar/cement paste is piped from a supply source (not shown), is sent out from a supply 34, a pipe 38, and an injection port 35, and is applied to a repair area such as the back side of rolled concrete in a known manner from a nozzle or the like. Injected. At this time, the pressure signal detected by the pressure sensor 37 is
The signal is amplified and sent to the pressure setting meter 26.

Here, as ^shown in FIG.
1 to 2Kg/cm ² and start the injection. As the pressure of the mortar-cement paste passing through pipe 38 increases, pressure needle 52 moves clockwise (Step A). When the pressure needle 52 overlaps the upper pressure upper limit needle 50 (step B), a signal is generated, and this signal is sent to the control device 25. Then, the control section 25a starts the timer section 25b and outputs an operating signal for a minimum period of time, for example, 0.1 seconds to the operating section of the electromagnetic switching valve 42, switching the electromagnetic switching valve 42 to parallel connection (P), and switching the electromagnetic switching valve 44 to the operating section of the electromagnetic switching valve 42. The signal is output to the operating section of the electromagnetic on-off valve 44 to open it. This results in
Air in the air tank 24 flows from the circuit L1 to the working chamber A of the cylinder via the electromagnetic switching valve 42, moves the piston 41 to the right in the figure, and lifts the control valve 32 by a minimum lift, for example, 2 mm. At this time, the oil in the working chamber B is returned to the oil tank 43 via the line L2, but is throttled by the flow rate adjustment valve 45, thus avoiding an excessive drop in injection pressure due to the sudden opening of the control valve 32. . Note that the air in the oil tank 43 is released to the atmosphere via the electromagnetic switching valve 42 and the circuit L4. By opening the control valve 32, the mortar in the pipe 38 is returned to the mortar tank (not shown) through the return port 36, and therefore the injection pressure decreases (step C). Note that when the injection pressure reaches the upper limit pressure (steps D and F), the above control is performed to lower the injection pressure (steps E and G).
Here, if the injection pressure becomes stable, the lift of the control valve 42 is maintained (step H). in this case,
The electromagnetic on-off valve 44 closes the circuit L2 and serves to maintain the lift of the control valve 32. Injection pressure drops,
When the pressure needle 52 overlaps the lower limit pressure setting needle 51 (step I), the pressure setting meter 26 emits a signal.
This signal is sent to control device 25. Then, the control unit 25 outputs an actuation signal to the actuation part of the electromagnetic switching valve 42 to switch the electromagnetic switching valve 42 to the cross connection (C), and also outputs it to the actuation part of the electromagnetic on-off valve 44 to open the electromagnetic on-off valve. . As a result, air in the air tank 24 flows from the circuit L4 to the oil tank 43 via the electromagnetic switching valve 42. Pressed by this inflowing air, the oil in the oil tank 43 flows through the check valve 46 and the electromagnetic on-off valve 44 into the working chamber B of the cylinder 33 via the circuit L2, causing the piston 41 to move to the left and rapidly closing the control valve 32. speak. At this time, the air in the working chamber A is released to the atmosphere from the circuit L1 via the electromagnetic switching valve 42. This causes the injection pressure to rise rapidly again (step J). After performing such control and injecting for a predetermined time within the upper and lower set pressure limits, the injection is completed.

[Summary] As described above, the present invention can automatically control the injection pressure when injecting mortar/cement paste, and therefore has the following advantages.

1 Upper limit pressure and lower limit pressure can be set freely.

2. When the upper limit pressure is reached, the pressure does not drop all at once, but gradually, so that an excessive pressure drop is avoided, and when the lower limit pressure is reached, the pressure rises rapidly.

3. After setting the pressure range and turning on the power, the control becomes completely automatic, and the pressure monitor can be removed.

4. Since the device can be made compact, it does not pose a problem when moving around the construction site.

[Brief explanation of the drawing]

FIG. 1 is an overall front view showing an embodiment of the present invention;
Figure 2 is a side view of Figure 1, Figure 3 is a detailed sectional view of the paste control section, Figure 4 is a circuit diagram, Figure 5 is a detailed view of the pressure setting meter, and Figure 6 is an injection showing the control status. The pressure/time characteristic diagrams, FIG. 7 and FIG. 8 are explanatory diagrams showing different conventional devices, respectively. 22... Paste control unit, 25... Control device,
26...Pressure setting meter, 32...Control valve, 33
... Hydraulic pneumatic piston cylinder, 34 ... Supply port,
35...Inlet, 36...Return port, 37...
Pressure sensor, 42...electromagnetic switching valve, 44...electromagnetic shut-off valve.

Claims (1)

[Scope of utility model registration request] A low-pressure automatic control device used when back-filling mortar/cement paste is equipped with a control valve that communicates with the return port between the paste supply port and the injection port, a pressure sensor on the injection port side, and a control valve that communicates with the return port between the paste supply port and the injection port. Equipped with a control device that issues a valve open signal to the actuator of the control valve for a certain period of time set by a timer based on a signal from the pressure sensor, and a switching valve that holds the actuator in the valve open state when there is no signal from the pressure sensor. A low-pressure automatic control device for mortar/cement paste injection, which is characterized by: