JPS61103070A - Three-way flow regulating valve for grout - Google Patents

Abstract

PURPOSE:To prevent a valve rod from wear by providing a truncated conic end, provided in the center with a recess, of a valve body for regulating flow between the valve body and an opening of a sleeve. CONSTITUTION:A sleeve 15 having an opening in the side wall is fixedly inserted in a valve case 14. A valve rod 17 is provided on the end with a screwed hole, and an end of a valve body 16 has a truncated conical configuration provided in the center with a recess. When a bolt 28 extending through a through hole of the valve body 16 is screwed into a treaded hole of the valve rod to mount the valve body 16 on the valve rod 17, the head of the bolt 28 is received in the recess of the valve body 16. Buffer members 30, 31 prevent the valve body 16 and a valve rod protecting pipe 21 from breakage at the contact portions between the valve body 16 and said pipe 21 and between said pipe 21 and a washer 22 to prevent the valve rod 17 from wear due to intrusion of grout.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-way flow rate regulating valve for use in a grout injection control system used in ground improvement methods for dam construction work.

Normally, in ground improvement work that semi-improves the ground by injecting grout made mainly of cement and water into the ground, the flow rate and pressure are maintained within specified values depending on the conditions and depth of the ground to be injected. Construction is instructed by construction specifications, etc.

One way to maintain the flow rate and pressure of grout injected into the ground within standard values is to use a variable discharge type grout pump.In the initial stage of injection, the grout is injected while maintaining the flow rate at the specified value, and the pressure is gradually increased. A method is known in which when the grout pressure increases and reaches a predetermined value, the discharge amount of the grout pump is gradually reduced to maintain the pressure at the predetermined value while injecting. However, in this method, the discharge rate of the grout pump decreases as the injection progresses, and eventually becomes a minute flow rate of several nanometers per minute or less. If such small flow rates are continuously injected, cement particles in the pipes will settle and begin to harden, clogging the pipes, and if the pipes are long, cleaning and other maintenance will take a lot of time. In addition, variable discharge type grout pumps are large, have poor workability on site, and are expensive, so there are very few opportunities for variable discharge type grout pumps to be used for grout injection.

For this reason, a small and inexpensive constant discharge type grout pump is usually used, and the grout storage tank and the suction port of the grout pot are connected by a suction pipe, and a supply pipe is connected to the discharge port of the grout pump. A branch point is provided at the end of the branch point, and the return pipe for returning excess grout to the storage tank, suction pipe, or suction port of the grout pump is connected to the injection pipe, and automatic three-way flow rate adjustment is performed at the branch point. Along with arranging the valve,
A flow rate detector that detects the flow rate of grout flowing through the injection pipe, that is, the injection amount, and a pressure detector that detects the injection pressure are disposed in the injection pipe, and a signal detected by the flow rate detector and the pressure detector; Either set the specified values of flow rate and pressure stipulated by construction specifications etc. in the flow rate and pressure control device, or specify the specified values of flow rate and pressure transmitted from the grout management device, etc. of the row section stored in advance (hereinafter set). A method was developed to control the injection amount and pressure by comparing the detected value with a flow rate pressure control device and operating an automatic three-way flow rate adjustment valve so that the detected value approaches the set value. -2O
The application has been filed as No.

In this method, since the injection resistance of the ground is low at the beginning of grout injection, the pressure does not rise against the flow rate and pressure limits stipulated in the construction specifications, etc., and the flow rate tends to exceed. In the final and final stages, the pressure tends to rise and exceed the specified limit, and in the middle stage, a phenomenon occurs in which the flow rate and pressure exceed at the same time or alternately.

That is, the initial stage of grout injection requires quantitative injection, the middle stage requires simultaneous or alternating control of quantitative and constant pressure injection, and the final stage requires constant pressure injection control, and the flow rate tends to gradually decrease as the injection resistance increases.

In the control to maintain these flow rates and pressures at specified values, excess grout is removed using automatic three-way flow control valves installed at the branch points of the supply pipe, return pipe, and injection pipe. Returning to the storage tank, suction line or suction of the grout pump results in controlled injection volume. In addition, by adjusting the opening of the automatic three-way flow regulating valve mentioned above, when the injection amount changes, the pressure changes due to the resistance of the ground, so pressure control is similar to flow control, and the opening of the automatic three-way flow regulating valve installed at the branch point can be controlled. can be controlled by

According to the method described above, the only part of each piping route that is likely to be clogged due to hardening of cement is the short injection pipe.
Because it requires less maintenance work and is superior in workability compared to the variable discharge type grout pots mentioned above, in dam construction etc., it is necessary to install fixed discharge type grout pots at branch points of supply pipes, return pipes, and injection pipes. It is extremely effective to use a grout injection control system in combination with an automatic three-way flow control valve.

This is a phenomenon that often occurs during low-pressure injection of consolidation grout and blanket grout that treats the surface layer of the ground.When returning surplus grout to a storage tank using the automatic three-way flow control valve described above, pressure loss in the return pipe occurs. When the set injection pressure is lower than the sum of the head caused by the height difference between the storage tank and the injection port (more precisely, the position of the pressure detector) If grout flows in by gravity at a flow rate greater than the specified flow rate, the grout injection control system that combines the constant discharge type grout pump and automatic three-way flow rate adjustment valve described above can also arbitrarily adjust the flow rate on the injection pipe side. It is possible to control the injection flow rate and pressure under any conditions, and the dam construction method for ground improvement work can be said to be the most effective grout injection control system.

However, in the three-way flow control valve of the automatic three-way flow control valve provided for such a grout injection control system,
When rubber is used for the valve seat, if the passing fluid contains cement particles and the injection pressure is high, the pressure difference generated between the supply side and return side of the three-way flow f# regulating valve will be large ( As a result, the fluid passes through the valve seat at a flow rate proportional to the pressure difference, and the abrasion caused by the cement particles is so severe that even specially selected wear-resistant rubber may become unusable during use. Therefore, in order to increase the wear resistance of the valve seat, it is possible to make the valve seat as well as the valve body from ceramics, but due to the problem of misalignment between the two valve seats on the return side and injection side and the valve body. The structure is complicated and requires high precision, making it difficult to provide a three-way flow rate regulating valve at a low cost, and there are problems with on-site maintenance.

Therefore, a three-way flow rate regulating valve for grout was developed in Japanese Patent Application No. 3G-/'G9FU, but as a result of experiments, the following problems were found. (1) The nut that fixes the valve body and the tip of the threaded part of the valve stem are worn out by the flow of grout. (
2) If the valve body is made into a thin plate, the corners of the valve body are likely to be damaged due to contact with the sleeve when the valve body slides or rotates, or during disassembly and assembly for inspection and cleaning. (3) The jet of grout may enter through the delicate gap between the valve body and the valve stem protection tube, causing wear on the valve stem.

The invention was made in view of the above, and the three-way flow rate regulating valve for grout of the present invention includes a sleeve having an opening in the side wall disposed inside the valve case, and a sleeve inserted into the sleeve that slides or rotates. a valve body that can slide and move and adjust current flow between the valve body and the opening of the sleeve, and an inflow port is provided in the valve case in communication with the opening of the sleeve; In the above-mentioned three-way grout flow regulating valve with outlet ports on both sides of the sleeve, the tip of the valve body has a truncated shape with a recess in the center to accommodate the head of the bolt that attaches the valve body to the valve stem. It is characterized by its conical shape.

The present invention will be described in detail below with reference to embodiments of the accompanying drawings. FIG. 1 shows a system diagram of a grout injection control system/example, in which 1 is grout temporarily stored in a storage tank 2; The grout 1 in the storage tank 2 is constantly stirred by the stirrer 3. Further, the storage tank 2 and the suction port of the grout pump 4 are connected by a suction pipe line 5, and the discharge port of the grout pump 4 is connected to a supply pipe line 6.

The tip of the supply pipe 6 is connected to the inflow lower a of the automatic three-way flow rate adjustment valve 7, and the return pipe 8 is connected to the outlet of the automatic three-way flow rate adjustment valve 7. The grout is returned to the storage tank 2. In addition, an injection pipe 9 is connected to the other outflow 07c of the automatic three-way flow rate adjustment valve 7, and the injection pipe 9 is connected to an injection pipe 10 that is provided by drilling into the ground.
The injection pipe 9 is connected to the injection port 10a, and the injection pipe 9 is provided with a flow rate detector 11 and a pressure detector 12 for detecting the pressure inside the injection pipe. That is, the flow rate detector 11 and the pressure detector 1
The flow rate and pressure signal detected by 2 is compared with preset flow rate and pressure set values, and the flow rate pressure control device 13 controls the automatic three-way flow rate adjustment valve so that the detected value approaches the set value. It is configured to operate T.

In the grout injection control system described above, the injection pressure is
If the head is higher than the sum of the head due to the pressure loss of the return pipe 8 and the head due to the height difference between the inlet 10a and the storage tank 2, the opening degree of the flow path on the outlet Tb side of the automatic three-way flow rate adjustment valve 7 should be adjusted appropriately. The injection pressure can be controlled to the set flow rate and pressure by adjusting to Or, if grout is injected by gravity at a flow rate higher than the set flow rate due to the low injection resistance of the ground, the injection can be carried out by appropriately adjusting the opening degree of the flow path on the outflow 07c side of the automatic three-way flow rate adjustment valve 7. The grout flow rate and pressure can be controlled to set values.

An example of a three-way flow rate regulating valve most suitable for the mechanical 30,000 flow mA'7M valve in the above-mentioned grout injection control/stem will be explained with reference to FIG.

FIG. 2 shows a cross-sectional view of the three-way flow rate regulating valve, in which a sleeve 15 having an opening in the side wall is fitted and fixed in the valve case 14, and the opening 15a is connected to the inflow lower a provided in the valve case 14. is connected to. Also, inside the sleeve 15 is a valve 81 driven by a drive device (not shown).
A valve body 16 integrally attached to the tip of the valve body 7 is loosely inserted so as to be slidable or rotatable. A screw hole is provided at the tip of the valve stem 17, and the tip of the valve body 16 has a truncated conical shape with a concave portion in the center, and the valve body 16 is fitted onto the tip of the valve stem 17. When the bolt 28 is inserted into the screw hole of the one-sho rod 17 through the through hole of the valve body 16 and the valve body 16 is attached to the valve stem 17, the head of the bolt 28 is stored in the recess of the valve body 16. . The teeth 30 and 31 attach the valve body 16 to the valve stem 17 with the washer 29.
When tightening and fixing with bolt 28 through
In order to prevent the valve body 16 and the valve stem protection tube 21 from being damaged at the contact area between the valve body 16 and the valve stem protection tube 21 and the contact area between the valve stem protection tube 21 and the washer 22 due to the tightening force of 8. This is a buffer member provided to prevent wear of the valve stem 17 due to infiltration of grout from the delicate gap in the contact area.

Further, a sleeve holder 18 is provided on one side of the valve case 14.
A seal case 19 is integrally attached to the other side by a coupling member such as a bolt (not shown). The sleeve presser 18 is provided with an outflow lower C.
Since there is no liquid sealing part with the valve stem 17, it is normally connected to the high pressure side flow path, that is, the injection pipe 9, and the outlet provided on the other side of the valve case 14 is connected to the seal case 19 and the valve a! Since it communicates with the liquid seal section 17, it is often used as a low-pressure side flow path in order to reduce the load on the liquid seal section, and is usually connected to the return pipe line 8.

20 is a valve chamber protection pipe fitted into the valve case 14 adjacent to the sleeve 15; 21 is a valve stem protection pipe fitted externally to the palr, including the washer 22 fitted externally to the valve stem 17; Although it is not essential for the function of the three-way flow rate regulating valve, it is used to prevent wear inside the valve due to the jet of grout containing cement generated by the gap between the opening 15a provided in the sleeve 15 and the valve body 16. 15, valve body 1
If 6 and 6 are made of ceramic, it will become a three-way flow regulating valve with excellent wear resistance.

In addition, 23 is an O-IJ ring provided between the valve case 14 and the sleeve retainer 18, 24 is an O-ring provided between the valve case 14 and the sleeve 15, and 25 is an O-ring provided between the valve case 14 and the seal case 19. Q IJ
7 and 26 are 01J rings provided between the seal case 19 and the valve stem 17, and 27 is used to prevent cement etc. from entering the O-ring 26 due to sliding or rotational sliding of the valve stem 17. This is a dust seal installed in the

The three-way flow regulating valve described above constitutes an automatic three-way flow regulating valve by attaching a driving device to the seal case 19 using bolts or the like.

In the automatic three-way flow rate regulating valve described above, the valve body 16 slides or rotates within the sleeve 15 by driving the drive device, but as shown in the second figure, the valve body 16 moves through the opening 15a of the sleeve 15. When the grout flows in from the inflow lower a, when it passes through the opening 15a, it is divided by the valve body 16 into the outflow lower C side and the outflow lower B side, and according to the area of the opening 15a divided by the valve body 16 Outflow lower c
This determines the flow rate of grout flowing to the top and bottom sides. Therefore, valve body 1
By arbitrarily adjusting the position of 6, the flow rate of both the outflow lowers C and N can be adjusted arbitrarily, and this valve is extremely suitable as an automatic three-way flow rate adjustment valve in the Geraud injection control system shown in FIG.

As described above, the opening 15a is divided by the valve body 16,
The divided area determines the flow rate of the grout flowing to the outflow lowers C and C. A flow rate and pressure control device that controls the operation of the automatic three-way flow rate adjustment valve 7 moves the valve body 16 by sliding or rotating within the sleeve 15 to change the divided area of the opening 15a. However, if the displacement of the valve body 16 is proportional to the rate of change in the divided area, and the rate of change is the same regardless of the position of the valve body, it depends on the injection conditions and pump specifications. More accurate control can be achieved if stable control is possible without any distortion, and if the ratio of change in the divided area to the displacement of the valve body 16 is small. The shape of the opening 15a of the sleeve 15 that satisfies this condition is such that its width is the same regardless of the position of the valve body 16, that is, it is an opening in which the opposite sides of the sleeve 15 in the central axis direction are parallel to each other, and The narrower the distance between the two surfaces, the more accurate the control can be. However, it is important that the spacing between the two sides is such that part or all of the opening will not be easily blocked by lumps other than cement particles that are sometimes included in the grout that is passing through, and for this purpose the width of the opening must be between 3 and 6.
It is preferable that the grain be of a fine grain. As described above, when the openings are elongated holes with the same width along the central axis direction of the sleeve, the movement length of the valve body 16 and the area of one of the openings divided by the valve body 16 are in a proportional relationship. .

Since the valve body 16 is configured to slide or rotate within the sleeve 15, there is a slight gap between the valve body 16 and the sleeve 15, and grout may leak from this gap. Naturally, this occurs, but the outflow lower c is the injection pipe 9.
Also, if the outflow port is connected to the return line 8, when the outflow port IC is closed, it is the time when no injection is performed, so the pump 4 can be stopped (and the pump 4 should be stopped). Since a pump with a valve body 16 is used, there is no need to completely close the outlet Ib side, and leakage from the gap between the valve body 16 and the sleeve 15 does not pose a practical problem.

In the present invention, the valve body or the sleeve can be made of alumina-based ceramics or cemented carbide such as Toughgesten Carbide to provide wear resistance.

Since the three-way flow pipe regulating valve of the present invention is configured as described above, when used in the grout injection control system shown in the first diagram, the three-way flow pipe regulating valve of the present invention can be used for the grout injection control system shown in the first diagram. When the set injection pressure is lower than the sum of the lifting heads, and when the ground injection resistance is low (even if grout exceeding the set flow rate attempts to flow in by gravity, the flow rate and pressure must be kept within the specified values). It can be held while injecting grout, maintenance is easy, and injection management can be further improved. Since it is mainly composed of a valve body that divides the grout from the inlet, the structure is extremely simple and maintenance is easy. When made of wear-resistant materials such as hard alloys, they are highly durable and do not need to be replaced as frequently as rubber valve seats, and the structure of the valve body and sleeve is simple and can be manufactured at low cost. have

Brief explanation of the Hiroguchi side The attached box 1 shows an embodiment of this invention, and the first
The figure is a system diagram of an example grout injection control system, and FIG. 2 is a sectional view of an example three-way flow regulating valve.

7a...Inlet, 7b, 7c...Outlet, 14...
Valve case, 15...-sleeve, 15a...-opening, 16... valve body

Claims (3)

[Claims] (1) Flow rate is adjusted between a sleeve that is disposed inside the valve case and has an opening in the side wall, and the opening of the sleeve that is inserted into the sleeve and moves by sliding or rotating. A three-way flow rate regulating valve for grout having a valve body that can be connected to the sleeve, an inlet in the valve case communicating with the opening of the sleeve, and an outlet on both sides of the sleeve; A three-way flow rate regulating valve for grout, characterized in that the tip shape is a truncated conical shape with a recess in the center for housing the head of a bolt for attaching the valve body to the valve stem. (2) The three-way flow rate regulating valve for grout according to claim 1, wherein the opening of the sleeve is an elongated hole of the same width along the central axis direction of the sleeve. (3) The three-way flow rate regulating valve for grout according to claims 1 and 2, wherein the valve body or the sleeve is made of ceramics or a cemented carbide such as tungsten carbide.