JPS6228575A - Three-way flow-rate adjusting valve for grout - Google Patents

Abstract

PURPOSE:To improve the control characteristic without improving the working precision by forming the shape of the top edge of a valve piece into cylindrical form and installing a liquid sealing member onto the periphery at the center part. CONSTITUTION:Inside a valve case 14, a sleeve 15 having an opened port on the side wall is inserted and fixed, and the opened port 15a communicates to an inflow port 17a formed onto the valve case 14. Inside the sleeve 15, a valve piece 16 integrally installed at the top edge of a valve rod 17 driven by a driving device is inserted in slidable ways or in turnable and slidable ways. The shape of the top edge of the valve piece 16 is a cylinder form having a recessed part at the center, and a liquid sealing member 32 is formed on the periphery of the center part. The valve rod 16 is fitted at the top edge of the valve rod 17, and a bolt 28 is screwed into the screw hole at the top edge of the valve rod 17, penetrating through the through-hole on the valve piece 16, and the valve piece 16 is installed onto the valve rod 17, and then the head part of the bolt 28 is accommodated into the recessed part of the valve body 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a three-way flow fIkv for use in a grout injection control system used in ground improvement methods for dam construction work, etc.
4 Regarding valve adjustment.

Usually, in ground improvement work that improves the ground by injecting grout made mainly of cement and water into the ground, the work is carried out by maintaining the flow rate and pressure within specified values depending on the conditions and depth of the ground to be injected. This is instructed by the construction specifications, etc.

One way to maintain the flow rate and pressure of grout injected into the ground within specified values is to use a variable discharge type grout pump.In the initial stage of injection, grout is injected while maintaining the flow rate at the specified value, and the pressure gradually increases. A method is known in which when the pressure rises to 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 amount of the grout pump decreases as the injection progresses, and eventually becomes a minute flow rate of several I 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. However, since variable discharge type grout pumps are large, have poor workability on site (and are expensive), there are extremely few occasions when variable discharge rate grout pumps are used for grout injection.

For this reason, a small and inexpensive fixed-discharge type grout pump is usually used, and in addition to connecting the grout storage tank and the suction port of the grout pump with a suction pipe, a supply pipe is connected to the discharge port of the grout pump. At the same time, a branch point is provided at the end of the branch point, and a return line for returning excess grout to the storage tank, suction line, or suction port of the grout pump is connected to the injection line, and an automatic three-way connection is established at the branch point. Along with installing a flow rate adjustment 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 set the specified values of flow rate and pressure (hereinafter referred to as set values) transmitted from an external grout management device etc. stored in advance. ) was developed using a flow rate and pressure control device, and an automatic three-way flow rate regulating valve was operated so that the detected value approached the set value, thereby controlling the injection amount and pressure. ! ;g
It has been filed as No. 3.

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 stage, the pressure tends to rise and exceed the specified value, 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 degree 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. 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 pumps mentioned above, fixed discharge type grout pumps are used in dam construction, etc., as well as at branch points of supply pipes, return pipes, and injection pipes. It is extremely effective to use a grout injection control system that combines an automatic three-way flow control valve installed in When returning surplus grout to a storage tank, etc. using an automatic three-way flow control valve, the vibration caused by the pressure loss in the return pipe and the height between the storage tank and the injection port (more precisely, the position of the pressure detector) When the set injection pressure is lower than the sum of the heads due to the difference, or when the injection resistance of the ground is low and grout exceeding the set flow rate flows by gravity, use the fixed discharge type grout pump described above and the automatic grout pump. The grout injection control system combined with a three-way flow rate adjustment valve can arbitrarily adjust the flow rate on the injection pipe side, making it possible to control the injection flow rate and pressure under any conditions, making it ideal for ground improvement work in dam construction methods. This can be said to be a very 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,
If rubber is used for the valve seat, if the passing fluid contains cement particles and the injection pressure is high, the pressure difference between the supply side and return side of the three-way flow control valve will increase.
Fluid passes through the valve seat at a flow rate proportional to the pressure difference, and wear caused by cement particles is so severe that even specially selected wear-resistant rubber may become unusable during use. Based on this, in order to increase the wear resistance of the valve seat, it is possible to make the valve seat from ceramics as well as the valve body, but there is a problem of misalignment between the two valve seats on the return side and injection side and the valve body. Since the structure has become complicated and highly precise, it has become difficult to provide a three-way flow regulating valve at a low cost.
There may be problems with on-site maintenance.

Therefore, a three-way flow rate regulating valve for grout was developed as disclosed in Japanese Patent Application No. 1987-22'101.9, and as a result of experiments, the smaller the difference between the outer diameter of the valve body and the inner diameter of the sleeve, the smaller the difference between the outer diameter of the valve body and the inner diameter of the sleeve. It was found that the higher the processing precision of the valve body and sleeve, the better the control characteristics.

However, increasing machining accuracy would increase costs, so this invention was made to improve control characteristics without increasing machining accuracy.The three-way flow rate regulating valve for grout of this invention is A sleeve having an opening in a side wall disposed in a valve case and a sleeve that is inserted into the sleeve and moves by sliding or rotating, and which adjusts the flow rate between the sleeve and the opening of the sleeve. In the three-way flow rate regulating valve for grout, the three-way flow rate regulating valve for grout has a valve body that can be opened, an inlet is provided in the valve case communicating with the opening of the sleeve, and an outlet is provided on both sides of the sleeve, and the tip shape of the valve body is is formed into a cylindrical shape, and a liquid sealing material is provided around the center thereof.

The present invention will be described in detail below with reference to embodiments of the accompanying drawings. FIG. 1 shows a system diagram of one example of a grout injection control system, in which 1 is grout temporarily stored in a storage tank 2; The grout 1 in the tank 2 is constantly stirred by a stirrer 3. In addition, the storage 4112 and the suction port of the grout pump 4 are connected by a suction pipe 5, and the grout pump 4
A supply pipe line 6 is connected to the discharge port.

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. Further, an injection pipe 9 is connected to the other outflow lower c of the automatic three-way flow rate regulating valve 7, and the injection pipe 9 is connected to an injection pipe 10 which is provided by drilling a hole in the ground.
The injection pipe 9 is connected to the injection port 10a of the injection pipe 9, 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 outlet type side flow path of the automatic three-way flow control valve 7 should be adjusted appropriately. By adjusting the flow f and pressure to the set value, the injection pressure is lower 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 injection port 10a and the storage tank 2. If grout is injected by gravity at a flow rate higher than the set flow rate due to low or low ground injection resistance,
By appropriately adjusting the opening degree of the flow path on the outflow 07c side of the automatic three-way flow rate regulating valve 7, the flow rate and pressure of the grout to be injected can be controlled to the set values.

Next, an example of a three-way flow rate adjustment valve which is most suitable for the automatic three-way flow rate adjustment valve in the above-mentioned grout injection control system will be explained with reference to FIG.

FIG. 2 shows a cross-sectional view of the three-way flow-i regulating valve 7, 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 located inside the valve case 14.
It communicates with the inflow port γa provided in the. Also sleeve 15
A valve body 16, which is integrally attached to the tip of a valve rod 1γ driven by a drive device (not shown), is loosely inserted into the interior so as to be slidable or rotatable. The tip of the valve body 16 has a cylindrical shape with four parts formed in the center, and a liquid sealing material 32 is provided around the center.The valve body 16 is fitted to the tip of the valve s1T, and the valve body When the bolt 28 is passed through the through hole 16 and screwed into the tip screw hole of the valve $17 and the valve body 16 is attached to the valve rod 17, the head of the bolt 28 is accommodated in the recess of the valve body 16. Further, 30 and 31 indicate that when the valve body 16 is tightened and fixed to the valve 1i117 with the bolt 28 via the washer 29,
The valve body 16 and the valve stem protection tube 21 are separated by the tightening force of the bolt 28.
This is to prevent the valve body 16 and the valve stem retaining pipe 21 from being damaged at the contact area between the valve stem retaining pipe 21 and the washer 22, and to prevent grout from entering through the delicate gap in the contact area. This is a buffer member provided to prevent the valve stem 17 from being worn out. Further, a sleeve retainer 18 is integrally attached to one side of the valve case 14, and a seal case 19 is attached to the other side by a coupling device such as a bolt (not shown).

The sleeve retainer 18 is provided with an outlet IC, and since the outlet IC does not have a liquid seal with the valve stem 17, it is normally connected to the flow path on the high pressure side, that is, the injection pipe line 9.

The outflow port provided on the other side of the valve case 14 communicates with the seal case 19 and the liquid seal part of the valve stem 17, so it can be used as a low-pressure side flow path to reduce the load on the liquid seal part. Many 1 are normally connected to the return line 8.

Reference numeral 70 denotes a valve chamber maintenance pipe fitted into the valve case 14 adjacent to the sleeve 15, 21 a valve stem maintenance pipe fitted externally to the valve stem 17, and the valve I! Although the valve 22 fitted on the sleeve 17 is not essential for the function of the three-way flow regulating valve, the interior of the valve is caused by a jet of grout containing cement generated by the gap between the opening 15a provided in the sleeve 15 and the valve body 16. This is to prevent wear of the sleeve 15 and valve body 1.
If 6 and 6 are made of ceramic, it will become a three-way flow regulating valve with excellent wear resistance.

Note that 23 is an O-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 the valve case 1.
4 and the seal case 19, 26
is an O-ring provided between the seal case 19 and the valve stem 17, and 27 is an O-ring provided by the sliding or rotational sliding of the valve stem 1T.
The above-mentioned three-way flow regulating valve, which is a dust seal provided to prevent cement etc. from entering the ring 26, can be made into an automatic three-way flow regulating valve by attaching a drive device to the seal case 19 using bolts, etc. Configure.

The automatic three-way flow control valve described above is equipped with a drive device (not shown).
The valve body 16 slides or rotates within the sleeve 15 due to the drive of the valve body 16 as shown in FIG.
When the tip of the sleeve 15 is above the opening 15a of the sleeve 15,
When the grout flowing in from the inflow lower a is passed through the opening 15a, it is divided by the valve body 16 into the outflow port Tc side and the outflow port side. The flow rate of the grout flowing to the 1b side is determined. Therefore, by arbitrarily adjusting the position of the valve body 16, the flow rate of both the outflow 07c and the outflow 07c can be adjusted arbitrarily, making it extremely suitable as an automatic three-way flow rate regulating valve in the grout injection control system shown in the first diagram. .

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 1 by sliding or rotating it 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. Opening 1 of sleeve 15 titrating this condition
The shape of 5a is such that its width is the same regardless of the position of the valve body 16, that is, it is an opening whose opposing C faces in the direction of the central axis of the sleeve 15 are parallel, and the narrower the interval between the two faces, the better the accuracy. can be controlled. However, it is important that the gap 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 passing through, and for this purpose the width of the opening must be 3 to 6 mm. degree is desirable. 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 and move within the sleeve 15, the valve body 16 is loosely inserted into the sleeve 15, and grout tends to leak from this gap. Since the liquid sealing material 32 is provided around the valve body 16, leakage of grout can be prevented, and since the liquid sealing material 32 is provided at the location where the flow velocity of the grout is the lowest, wear can be minimized. In addition, it is preferable that the liquid sealing material 32 is made of wear-resistant and elastic materials such as rubber, synthetic rubber, or synthetic resin. In this invention, the valve body or sleeve is The three-way flow rate regulating valve of the present invention is constructed as described above, and can be made of alumina-based ceramics or cemented carbide such as tungsten carbide to provide wear resistance. When used in the system, if the set injection pressure is lower than the sum of the head caused by the pressure of the return pipe and the head due to the height difference between the storage tank and the injection port, and if the flow rate is set low and the injection resistance of the ground is low. Even if the above grout tries to flow in by gravity, it is possible to maintain the flow rate and pressure within the specified value and inject the grout, and the sleeve also serves as a valve seat and the inside of the sleeve can be slid or rotated. Since it is mainly composed of a valve body that moves and diverts grout from the inlet port, the structure is extremely simple and maintenance is easy. By increasing the machining accuracy of the valve body and sleeve, it is possible to economically prevent grout leakage, and to construct a three-way flow rate regulating valve for grout with excellent control characteristics regardless of injection conditions. It is possible to reduce wear on the sleeve and the valve body, improving durability, and it is possible to withstand long-term use by simply replacing the liquid sealing material as a consumable item.

In addition, when the valve body and sleeve are made of wear-resistant materials such as ceramics such as alumina or cemented carbide such as tungsten carbide, they are highly durable and do not need to be replaced as often as rubber valve seats. The structure of the sleeve is simple and can be manufactured at low cost.

[Brief explanation of drawings]

The attached drawings show embodiments of the present invention, and the first
The figure is a system diagram of an example of a grout injection control system, and FIG. 2 is a sectional view of an example of a three-way flow rate regulating valve. 7a...Inlet, 7b.70...Outlet, 14...
・Valve case, 15... Sleeve, 15a... Opening, 16... Valve body %32 liquid sealing material

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 adjustment valve for grout, which has a cylindrical tip and a liquid sealing material surrounding the center. (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.