JP4881179B2 - Abrasive supply device and abrasive supply method - Google Patents

Description

  The present invention relates to an abrasive supply device and an abrasive supply method for pumping particulate abrasive stored in an abrasive supply tank through a supply pipe.

  Conventionally, as an abrasive material supply device for supplying an abrasive material used for abrasive water jet processing, an apparatus that uses an air compressor to pump from an abrasive material supply tank (pressure tank) stocked with an abrasive material is generally used. It is often used. In such a pressure-feed type abrasive material supply apparatus that feeds abrasive material, the inside of a pipe that feeds the abrasive material from the abrasive material supply tank to the abrasive nozzle is a compressed air pressure supply line.

  In this abrasive supply device, the pressure of the abrasive supply tank is increased or the valve at the outlet of the abrasive supply tank is opened to start pumping, and it takes several seconds until the abrasive actually flows and reaches the tip of the pipe. There is a delay of several tens of seconds. In the pressure-feed type abrasive material supply device, when supplying the abrasive material to the abrasive nozzle only by pressure feed, this supply delay becomes a problem.

As means for solving such a supply delay of the abrasive, for example, an abrasive supply device for water jet disclosed in Patent Document 1 is known.
In this device, in order to compensate for the delay in the supply of abrasives at the time of startup, an on-off valve is provided in the vertical part of the abrasive supply pipe, and an abrasive stock part for intentionally collecting abrasives is formed, so that the next on-off valve When the nozzle is opened, the abrasive accumulated in the abrasive stock portion is sprayed from the abrasive nozzle. In this case, the supply delay is dealt with by opening the abrasive supply valve earlier than the water jet ON.

Further, as an example of compensating for the instability of the supply amount of the abrasive, for example, an abrasive water jet abrasive supply device disclosed in Patent Document 2 is known.
This device is equipped with a weight meter (load cell) in the abrasive supply tank, measures the amount of abrasive used per unit time, and feeds back the amount of abrasive supplied to the valve opening of the abrasive flow control valve. It is adjusted.

  In addition, as an apparatus for adjusting the supply amount of the abrasive, for example, a grinding fluid ejecting apparatus disclosed in Patent Document 3 is known. This apparatus uses a discharge orifice for limiting the amount of abrasive flowing, and the discharge orifice is installed downstream of a baffle in an air isolator into which the abrasive is introduced.

FIG. 4 is a schematic cross-sectional view showing a weighing hopper of a conventional abrasive supply device.
As shown in FIG. 4, the conventional weighing hopper 100 has a supply pipe 200 installed on the closed upper surface, and a polishing material 300 fed by the supply pipe 200 with an internal pressure and a nozzle (not shown) provided at the downstream portion. ) Is discharged from the discharge port 110 on the bottom surface.

JP-A-5-301166 (see paragraphs 0011 to 0012) Japanese Patent Laid-Open No. 7-24737 (see paragraph 0016) Japanese Patent Laid-Open No. 9-168773 (refer to claim 1, claim 5, FIG. 1 and FIG. 2)

However, in the above-described abrasive feeding device of the pressure feeding method, when the abrasive is pumped, the distribution state of the abrasive in the supply pipe and the compressed air becomes uneven, and the flow of the abrasive in the supply pipe is irregular. There is a problem that the undulation and the flow velocity tend to be unstable.
As a result, there is a problem that the supply amount of the abrasive is always unstable and the follow-up to the opening and closing of the valve is also bad.

  In the water jet abrasive material supply device of Patent Document 1, when the on-off valve is opened, the abrasive material stored in the abrasive material stock part flows out at once, so the flow rate of the supplied abrasive material is uneven and stable. There was a problem that it could not be supplied in the state.

  In the abrasive water jet abrasive supply device of Patent Document 2, even if the abrasive flow rate is adjusted by the abrasive flow rate adjusting valve, the conveyance state of the pumping line is unstable, so the accuracy of the abrasive supply amount is high. It was within ± 30% of the reference value, and there was a problem with its accuracy.

  Further, in a batch type abrasive material supply device that supplies abrasive material in an abrasive material supply tank comprising a pressure tank as in Patent Document 2, when supplying abrasive material to the abrasive material supply tank, supply to the abrasive valve is performed. It had to be done after it stopped. In this case, when it takes a long time to perform one operation such as cutting, there is a problem that the operation such as cutting must be interrupted in order to replenish the abrasive.

  In such a case, conventionally, two abrasive supply tanks are installed, and the two supply pipes for pumping the abrasive are switched by a three-way valve, whereby the abrasives in the two abrasive supply tanks are alternately arranged. Although there is a means for supplying, there is a problem in that the valve is damaged by the high-pressure and high-density abrasive when switching the valve.

  The grinding fluid injection device of Patent Document 3 is excellent in that the flow rate of the abrasive can be accurately controlled to a set amount. However, if the supply amount of the abrasive is to be changed, the device is stopped and the discharge orifice is adapted. There is a problem that workability is poor and the supply amount of the abrasive cannot be changed in accordance with the cutting program because it is necessary to replace it with a different one.

  As described in Patent Document 3, the valve is normally configured such that an actuator including an air cylinder and a screw feed mechanism is connected in the valve opening / closing direction and is opened / closed by the actuator. When closing the valve, abrasive particles may enter between the valve and the valve seat. At this time, if the force for closing the valve is large, there is a problem that the valve or the valve seat is damaged by the abrasive particles that are caught.

Since 100% of the thrust force of the actuator connecting the valve and the actuator is loaded on the valve, the closing force becomes excessive, and the valve may be damaged by the force.
In order to avoid this problem, conventionally, the thrust of the actuator when closing the valve has to be reduced, and the opening / closing speed of the valve cannot be increased.

  Further, in the conventional weighing hopper 100 as shown in FIG. 4, since the internal air pressure is increased by the pressure for feeding the abrasive 300 through the supply pipe 200, the abrasive 300 is ejected vigorously from the discharge port 110. Therefore, there is a problem that the discharge amount of the abrasive 300 cannot be controlled.

  Accordingly, the present invention has been made to solve such problems, and an object thereof is to provide an abrasive supply device and an abrasive supply method that can supply an abrasive in a stable state.

In order to solve the above-mentioned problem, the invention of the abrasive material supply device according to claim 1 is an abrasive material supply tank comprising a pressure vessel for storing particulate abrasive material, and an air pressure is applied to the abrasive material supply tank. In the abrasive supply device, comprising: an air compressor for causing the abrasive supply tank to be connected; and a supply pipe for connecting the base end portion to the abrasive supply tank and pumping the abrasive in the abrasive supply tank. The supply pipe is suspended in the weighing hopper from above the weighing hopper whose top end is open, and the tip is in contact with the abrasive stored in the weighing hopper to supply the abrasive. Is installed in a state where the air pressure at the tip is attenuated to near atmospheric pressure by pressure loss, and the measuring hopper is connected to the discharging port formed at the bottom of the measuring hopper. Open And a funnel for introducing the abrasive discharged from the discharge port opened to the atmosphere into an abrasive suction tube connected to the abrasive nozzle, and the abrasive nozzle is connected to the abrasive nozzle. The abrasive in the funnel was sucked through the abrasive suction tube by the negative pressure of the water jet supplied to the provided super high pressure water inlet, and the abrasive and ultra high pressure water were mixed from the nozzle. It is characterized by injecting an abrasive jet .
Here, “near atmospheric pressure” means an atmospheric pressure that is substantially close to the atmospheric pressure at which the abrasive material naturally falls. For example, when the atmospheric pressure is set to 0 MPa, the internal pressure of the abrasive material supply tank is set to 0 MPa. When the abrasive particle size is # 80 to # 220, the inner diameter of the supply pipe is 12 mm, and the length of the supply pipe is 20 m, it is 0.002 MPa. Preferably, the air pressure at the tip of the supply pipe is 0.001 to 0.003 MPa.

According to the abrasive supply device of the first aspect of the present invention, the supply pipe is formed in such a length that the air pressure at the tip portion attenuates to near atmospheric pressure due to pressure loss. The abrasive can be pumped by air pressure from the base end connected to the tank. And since the pressure at the outlet side opening is almost the same atmospheric pressure as the atmosphere, the tip of the supply pipe is gently discharged so that the abrasive discharged from this outlet side opening naturally falls. Is done. As a result, the abrasive does not jet out of the supply pipe vigorously, the flow of the air and the abrasive at the outlet side opening of the supply pipe becomes uniform and flows regularly, and the flow velocity and supply amount of the abrasive Is stabilized.
Therefore, for example, when a needle valve is installed downstream of the supply pipe, the supply delay of the abrasive with respect to opening and closing of the needle valve can be eliminated.

According to the invention of the abrasive supply apparatus according to claim 1, the supply pipe has an upper surface portion arranged tip to the weighing hopper by hanging from above the weighing hoppers which is open to the atmosphere Therefore, when the amount of the abrasive stored in the weighing hopper increases, the supply of the abrasive is stopped because the abrasive abuts against the tip of the supply pipe to clog the supply pipe. Abrasive material is clogged in the supply pipe, and since the decompressed air is exhausted from the gap between the abrasive particles, a constant amount of the abrasive material is always stored in the weighing hopper, and the abrasive material at the orifice. When the amount is regulated, the air pressure is not affected.

According to the invention of the abrasive supply apparatus according to claim 1, the weighing hopper, and a needle valve for opening and closing the discharge port, and a funnel supplied is provided a discharge abrasive from the discharge port As a result, the abrasive is dropped into the funnel by opening the needle valve. All of the abrasive that has fallen into the funnel is introduced into the abrasive suction tube without spilling. Then, the abrasive is sucked into the abrasive nozzle by the negative pressure of the water jet, and is jetted as an abrasive jet.

The abrasive material supply device according to claim 2 is the abrasive material supply device according to claim 1 , wherein the needle valve has a tip angle of 10 to 90 degrees. A substantially rod-shaped valve body whose axial opening amount is moved by an actuator, an operating portion that is actuated by an output rod provided in the actuator to open the valve body, and a spring for closing the valve body The valve body and the operating portion are lowered by the spring force of the spring member and the weight of the valve body to close the discharge port .

According to the second aspect of the invention, the needle valve is configured such that the valve body has a tip angle of 10 degrees to 90 degrees, and the axial opening amount is controlled by an actuator with an encoder. This makes it possible to accurately regulate the amount of abrasive.

According to the invention of the abrasive supply apparatus according to claim 2, needle valve, the spring member for closing and actuating unit to open the valve body is operated, the valve body by an output rod provided in the actuator The output rod pushes and opens the valve body by the thrust of the actuator, and the valve body is closed by the spring force of the spring member. With this configuration, the needle valve is operated by the spring force of the spring member and the weight of the valve body when the valve body is closed, so that an unnecessary load is not required for closing the valve body.

An invention of an abrasive material supply method according to claim 3 is an abrasive material supply method using the abrasive material supply device according to claim 1 or 2, wherein the measuring hopper includes a plurality of the supply pipes. The abrasive supply tank is connected to each of the plurality of supply pipes. When the amount of abrasive in one of the abrasive supply tanks reaches a lower limit, the supply pipe is connected to the other abrasive supply tank. The abrasive is supplied from the other supply pipe to the weighing hopper.

According to the invention of the abrasive material supply method according to claim 3 , the abrasive material supply device has a plurality of supply pipes arranged in the weighing hopper, and an abrasive material supply tank is connected to each of the plurality of supply pipes, When the amount of abrasive in one abrasive supply tank reaches the lower limit, the abrasive is supplied from the other supply pipe connected to the other abrasive supply tank to the weighing hopper. For this reason, even if one abrasive supply tank is being replenished with the abrasive, the abrasive can be supplied to the weighing hopper from the other abrasive supply tank and the supply pipe. In this way, since the supply of the abrasive is not interrupted, continuous cutting for a long time is possible.

  According to the abrasive supply device according to claim 1 of the present invention, the flow of the air and the abrasive in the outlet side opening of the supply pipe is made uniform and flows regularly, and the flow rate and supply amount of the abrasive are reduced. Can be stabilized.

Further, according to the abrasive supply apparatus according to claim 1 of the present invention, the supply pipe, by abrasives accumulated is supplied to the weighing hopper to the tip portion abuts, so that the supply is automatically stopped Therefore, a constant amount of abrasive can always be stored in the weighing hopper.

According to the abrasive supply device of the first aspect of the present invention, all of the abrasive that has fallen into the funnel by opening the needle valve from the inside of the measuring hopper is introduced into the abrasive suction tube without spilling. Then, the workpiece is sucked into the abrasive nozzle by the negative pressure of the water jet, becomes an abrasive jet, and is stably jetted toward the workpiece to process the workpiece.

According to the abrasive supply device of the second aspect of the present invention, the needle valve is formed such that the valve body has a tip angle of 10 degrees to 90 degrees, and the axial opening amount is controlled by an actuator with an encoder. Thus, the amount of the abrasive can be regulated and sent out to an appropriate amount.

According to the abrasive supply device of the second aspect of the present invention, the needle valve is configured such that the output rod pushes and opens the valve body by the thrust of the actuator, and the valve body is closed by the spring force of the spring member. No more load than necessary to close the door. For this reason, even when the valve body is rapidly opened and closed, the valve can be prevented from being damaged by the biting of the abrasive.

According to the abrasive supply method according to claim 3 of the present invention, since the abrasive can be sent to the weighing hopper through a plurality of supply pipes, one abrasive supply tank is provided by the plurality of abrasive supply tanks and supply pipes. Even when the abrasive is being replenished, it is possible to supply the abrasive while automatically switching the supply piping supplied to the weighing hopper. For this reason, since the storage amount and supply time of an abrasive can be increased, it can be solved that the abrasive supplied to the weighing hopper is interrupted and insufficient. As a result, it is possible to stably supply the abrasive material from the abrasive material supply tank to the abrasive nozzle without stopping the abrasive material supply device even when cutting or the like is performed on the processing machine for a long time. .

Hereinafter, an abrasive supply device and an abrasive supply method according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
The abrasive material supply apparatus and the abrasive material supply method according to the present invention are not particularly limited as long as the abrasive material supply apparatus and the abrasive material supply method are apparatuses that pump the abrasive material to a desired device or the like by a supply pipe. In the following description, the case where it is simply used as a “processing machine” will be described as an example.
FIG. 1 is a layout view showing an abrasive supply device and an abrasive supply method according to an embodiment of the present invention. FIG. 2 is an enlarged view of a portion X shown in FIG.

≪Configuration of processing machine (Abrasive water jet processing machine) ≫
As shown in FIG. 1, the processing machine A uses, for example, a collision energy when a high-speed water jet obtained by pressurizing a fluid with a high-pressure pump and injecting the fluid from the abrasive nozzle 8 together with the abrasive B collides with the workpiece W. It is a device that performs cutting, cutting, peeling, and lifting. In such a processing machine A, water is usually used as the fluid, but a thickener may be added to improve the convergence of the jet and improve the cutting efficiency. Further, the processing machine A uses an abrasive (abbreviated material) B mixed in the fluid in order to increase the cutting force and enable cutting of steel, reinforced concrete, and the like. The processing machine A includes an abrasive nozzle 8 and an abrasive material supply device 1 for feeding the abrasive material B to the abrasive nozzle 8.

≪Abrasive composition≫
The abrasive B is made of a garnet abrasive or the like, which is an abrasive for abrasive water jet cutting, and has a particle size of about # 80 to # 220 depending on the type and use of the workpiece W. In the case of a garnet abrasive, the specific gravity of garnet stone is 4.1, while the garnet abrasive used contains air (46%), so the specific gravity is about 2.2.
The abrasive B may be other than a garnet abrasive such as alumina as long as there is a gap through which compressed air can pass between the particles of the abrasive B.

<Configuration of abrasive material supply device>
The abrasive material supply device 1 generates a water jet containing the abrasive material B by the abrasive nozzle 8 and supplies the abrasive material B to the abrasive nozzle 8 in the processing machine A that processes various workpieces W, for example. Device. The abrasive material supply apparatus 1 includes an abrasive material supply tank 2 composed of a pressure vessel for storing the abrasive material B, and an air compressor for loading the abrasive material supply tank 2 with air pressure for feeding the abrasive material B. 3, an electromagnetic on-off valve 14 for adjusting the supply of air pressure from the air compressor 3 to the abrasive supply tank 2, and a base end portion Pa connected to the abrasive supply tank 2, And a supply pipe P for pumping the abrasive B.

≪Configuration of abrasive supply tank≫
The abrasive supply tank 2 is a tank for temporarily storing the abrasive B supplied to the abrasive nozzle 8, and is composed of a sealed pressure vessel. The abrasive supply tank 2 includes an abrasive inlet 2a provided at the upper end, a compressed air inlet 2b provided at the upper portion in the vicinity of the abrasive inlet 2a, and an opening / closing valve provided at the bottom. And a discharge port 2c having (not shown). The abrasive B in the abrasive supply tank 2 flows into the supply pipe P by the air pressure from the electromagnetic on-off valve 14 when the on-off valve is opened.

Further, a sensor (not shown) is attached to the abrasive material supply tank 2, and the remaining amount of the abrasive material B in the abrasive material supply tank 2 is detected by the sensor. The abrasive material inlet 2a is a replenishment port for replenishing the abrasive material B into the abrasive material supply tank 2, and is openable and closable so that the inside of the abrasive material supply tank 2 can be sealed.
An air pipe 3a is connected to the compressed air introduction port 2b, and compressed air is sent from the electromagnetic on-off valve 14 through the air pipe 3a. The compressed air introduction port 2b may be provided with a pressure adjusting valve that adjusts the pressure of the compressed air from the electromagnetic opening / closing valve 14.
The discharge port 2c is formed in a substantially lower end of the bottom surface of the abrasive supply tank 2 which is formed in a substantially funnel shape and becomes narrower toward the lower end, and can be opened and closed by an on-off valve (not shown).

≪Configuration of air compressor and electromagnetic on-off valve≫
The air compressor 3 is for generating compressed air to be sent into the abrasive supply tank 2 and the supply pipe P, and an air pipe 3 a connected to the abrasive supply tank 2 is connected thereto. The pressure in the abrasive supply tank 2 is adjusted to, for example, 0.3 MPa by introducing compressed air from the electromagnetic on-off valve 14, and the abrasive B in the abrasive supply tank 2 and the supply pipe P is adjusted. It is the pressure source pressure that can be sent. The electromagnetic on-off valve 14 is a valve for adjusting the internal pressure of the abrasive supply tank 2 and is electrically connected to the control device 12.

≪Configuration of supply piping≫
The supply pipe P is a pipe for sending the abrasive B stored in the abrasive supply tank 2 to the weighing hopper 4, and the base end Pa is connected to the discharge port 2 c of the abrasive supply tank 2. The tip portion Pb is disposed on the weighing hopper 4. The supply pipe P is suspended from the upper side of the weighing hopper 4 whose upper surface is open to the atmosphere, and a tip end portion Pb is disposed in the weighing hopper 4. The tip portion Pb is installed so that the supply of the abrasive B is stopped when the abrasive B stored and accumulated in the weighing hopper 4 comes into contact therewith. In the supply pipe P, even if the flow of the abrasive B is stopped and the conveyance is stopped, the air decompressed through the gaps between the particles of the abrasive B clogged in the supply pipe P passes through and is discharged. It has come to be. Therefore, the supply pipe P can always store a certain amount of the abrasive B in the weighing hopper 4.

The supply pipe P is formed to have a length L such that the air pressure at the tip end portion Pb is attenuated to near atmospheric pressure due to the pressure loss in the pipe, so that the abrasive B can be sent stably. For example, the supply pipe P has an inner diameter of 12 mm and an overall length L of 20 m. And the pressure of the front-end | tip part Pb of the supply piping P is attenuate | damped to 0.002 MPa (2KPa = 0.02kgf / cm < ² >) when atmospheric pressure is set to 0 MPa.

≪Configuration of weighing hopper≫
The weighing hopper 4 is controllable so that the abrasive B introduced by the supply pipe P can be stably discharged at a predetermined amount from the discharge port 4b, and is formed in a substantially funnel shape. The weighing hopper 4 has a discharge valve 4b formed at the bottom, a needle valve 5 for opening and closing the discharge port 4b, and a funnel 7 for introducing the abrasive B discharged from the discharge port 4b into the abrasive suction tube T. , Is provided. In the weighing hopper 4, an opening 4a is formed at the upper end surface, a discharge port 4b is formed at the center of the lower end, and when the valve body 5a is opened, the stored abrasive B is discharged from the discharge port 4b to the funnel 7b. It is formed so as to be discharged naturally.

  The opening 4 a is a part for installing the valve body 5 a of the needle valve 5 and the supply pipe P in a state of being inserted into the measuring hopper 4. The opening 4a is always open and is in a state in which the atmosphere can flow, and at the center thereof, the substantially rod-shaped valve body 5a of the needle valve 5 is vertically arranged so as to be movable up and down, and the supply pipe P The tip end portion Pb is arranged in a state of hanging down to a predetermined height position.

  The discharge port 4b is an opening / closing outlet for discharging the abrasive material B in the measuring hopper 4, and is supplied and supplied by the valve body 5a depending on the degree of opening. Can be adjusted.

≪Needle valve configuration≫
The needle valve 5 is for adjusting the amount of the abrasive B that is dropped into the funnel 7 by closing and opening the discharge port 4 b of the measuring hopper 4. The needle valve 5 includes an operating portion 5b that is operated by an output rod 6a provided in the actuator 6 to open the valve body 5a, and a spring member SP for closing the valve body 5a. In the needle valve 5, for example, the tip angle θ (see FIG. 2) of the valve body 5a of the needle valve 5 is formed from 10 degrees to 90 degrees, and the axial opening amount H is controlled by an actuator 6 with an encoder. Is done.

  The valve body 5a is a rod-like member supported by a support member (not shown) so as to be movable in the vertical direction with respect to the discharge port 4b. The lower end portion is formed in a conical shape, and the upper end portion is substantially L-shaped. The formed operating portion 5b is integrally provided.

  The actuating portion 5b is pushed up by the output rod 6a of the actuator 6 and lifts and opens together with the valve body 5a, and is lowered and closed by the spring force of the spring member SP and the dead weight of the valve body 5a. For example, it consists of the lever-shaped thing integrally formed in the valve body 5a.

≪Actuator configuration≫
The actuator 6 controls the opening H in the axial direction of the valve body 5a of the needle valve 5 to drop from the measuring hopper 4, and is supplied to the abrasive nozzle 8 via the funnel 7 and the abrasive suction tube T. It is an apparatus for adjusting the supply amount of B. The actuator 6 is configured by, for example, a ball screw mechanism including an encoder. In the opening / closing control of the needle valve 5, the actuator 6 is configured to open the valve body 5a by raising the output rod 6a by the thrust of the actuator 6 when the valve body 5a is opened and the abrasive B is supplied. .

≪Configuration of spring member≫
The spring member SP is a spring for closing the needle valve 5, and is made of, for example, a compression coil spring and supported in a compressible state by a support member (not shown).

≪Funnel structure≫
The funnel 7 is for sending the abrasive B dropped from the measuring hopper 4 to the abrasive suction tube T by opening the valve body 5 a of the needle valve 5. The funnel 7 is connected to an abrasive nozzle 8 with an abrasive suction tube T interposed therebetween.

≪Abrasive nozzle configuration≫
The abrasive nozzle 8 sucks the abrasive B through the abrasive suction tube T by the negative pressure of a water jet from a pipe (not shown) connected to the abrasive nozzle 8, and the abrasive B is sucked into the ultrahigh pressure water. This is an injection nozzle of the processing machine A that injects the abrasive jet mixed with the workpiece W onto the workpiece W. The abrasive nozzle 8 includes an ultra-high pressure water inlet 8a to which a water jet is supplied, an abrasive inlet 8b to which an abrasive B is supplied in communication with a supply port Tb of the abrasive suction tube T, and an abrasive B And an on / off valve 9 for performing opening / closing control for switching between injection and stoppage of injection from the nozzle 8c.

  In the abrasive nozzle 8, for example, an abrasive jet sprayed at a high speed by applying high pressure to water is sprayed onto the workpiece W on the table 10 to perform water jet processing.

<Configuration of on / off valve>
The on / off valve 9 is a valve for turning on and off the abrasive nozzle 8 to open and close the valve to inject and stop the abrasive jet, and is electrically connected to the control device 12.

<Configuration of control device>
The control device 12 controls the electromagnetic on-off valve 14 and the actuator 6 to operate and stop the supply of the abrasive B by the abrasive supply device 1, and also turns the on / off valve 9 on and off to turn on the abrasive nozzle 8 of the processing machine A. It is a device that stops the operation of the high-pressure water supply and the like.

≪Action≫
Next, the operation of the abrasive supply device and the abrasive supply method according to the embodiment of the present invention will be described with reference to FIG.
When processing the workpiece W by the processing machine A, first, the abrasive B is supplied to the abrasive supply tank 2 from the abrasive input 2a and the abrasive input 2a is closed.
Next, the electromagnetic on-off valve 14 is turned on, compressed air is sent into the abrasive supply tank 2 from the compressed air inlet 2b via the air pipe 3a, and the pressure in the abrasive supply tank 2 is reduced to, for example, 0. 3 MPa.

  Then, the abrasive material B in the abrasive material supply tank 2 is pressed by the air pressure of the air compressor 3 and flows in the supply pipe P together with the compressed air, and falls into the measuring hopper 4 from the front end portion Pb and stored. .

  At this time, the supply pipe P is formed in such a length that the air pressure at the tip end portion Pb is attenuated to 0.002 MPa near atmospheric pressure due to pressure loss, and thus connected to the abrasive supply tank 2 in the state of a pressure vessel. The abrasive B is slowly pumped by air pressure from the base end portion Pa. As a result, the flow of the air and the abrasive B in the front end portion Pb of the supply pipe P is made uniform and regularly flows, the flow rate and supply amount of the abrasive B are stabilized, and the supply delay of the abrasive B is reduced. Can be resolved.

In the weighing hopper 4, the tip end portion Pb of the supply pipe P is suspended from above the weighing hopper 4 and disposed in the weighing hopper 4, so that the abrasive B is discharged at such a weak pressure that it falls by its own weight. . For this reason, when the amount of the abrasive B stored in the weighing hopper 4 increases, the accumulated abrasive B comes into contact with the front end portion Pb of the supply pipe P to make the supply pipe P clogged. The supply of B stops.
The supply pipe P is automatically stopped when the tip end Pb abuts against the abrasive B gradually increased in the weighing hopper 4, so that a constant amount of abrasive B is always stored in the weighing hopper 4. I can keep it.

  Thus, when the abrasive B is clogged in the supply pipe P, the decompressed air is exhausted from the gaps between the particles of the abrasive B, so that a constant amount of the abrasive B is always kept in the weighing hopper. 4 and the upper portion of the weighing hopper 4 is open, so that the abrasive B is not affected by the air pressure for pressure feeding.

When processing the workpiece W by the processing machine A, the control device 12 is operated to open the on / off valve 9 to send a water jet to the abrasive nozzle 8 and to turn on the actuator 6 to turn on the valve body 5a of the needle valve 5. open.
Then, the abrasive B in the weighing hopper 4 is dropped onto the funnel 7 in an amount corresponding to the opening amount H (see FIG. 2) of the valve body 5a when the needle valve 5 is opened. The abrasive B falling on the funnel 7 is sucked from the funnel 7 through the abrasive suction tube T to the abrasive nozzle 8.

  Then, an abrasive jet in which the abrasive B and the water jet are mixed is jetted from the abrasive nozzle 8 toward the workpiece W on the table 10 of the processing machine A to process the workpiece W.

  Further, when the supply of the abrasive B from the abrasive supply device 1 to the abrasive nozzle 8 is stopped, the controller 12 is operated, the actuator 6 is operated, and the valve body 5a of the needle valve 5 is closed. The abrasive B is stopped from flowing downstream from the weighing hopper 4. Furthermore, the supply of ultra high pressure water to the abrasive nozzle 8 is also stopped by turning off the on / off valve 9.

  When the needle valve 5 is stopped, the valve body 5a is closed by its own weight and the spring force of the spring member SP, so that an excessive load is not required for closing the valve body 5a. Even when the opening / closing speed of 5a is 100 mm / s or more and the opening / closing time of the valve body 5a is 0.05 to 0.15 seconds), the weighing hopper 4 can be prevented from being damaged by the biting of the abrasive B.

The needle valve 5 in the measuring hopper 4 drops an appropriate amount of abrasive B that can be changed from the measuring hopper 4 into the funnel 7 by controlling the actuator 6 with an encoder with the encoder 5 by the control device 12. Thus, the abrasive nozzle 8 can be supplied and the supply amount of the abrasive B can be controlled with high accuracy of ± 5% and sent out.
As a result, when the workpiece W is cut by the processing machine A, an abrasive jet always containing a desired amount of abrasive B is continuously injected from the abrasive nozzle 8 toward the workpiece W and continuously. Can be processed.

[Modification]
The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the technical idea. The present invention extends to these modifications and changes. Of course.

  FIG. 3 is a view showing a modified example of the abrasive material supply apparatus and the abrasive material supply method according to the embodiment of the present invention. FIG. 3 (a) shows the second polishing by supplying the abrasive material from the first supply pipe to the weighing hopper. An explanatory view showing a state when the abrasive supply tank is replenished with the abrasive, (b) is a lower limit of the supply amount of the abrasive in the first supply pipe, and the abrasive is supplied to the weighing hopper through the second supply pipe. FIG. 5C is an explanatory diagram showing a state when the first abrasive material supply tank is supplemented with the abrasive material and the abrasive material in the second abrasive material supply tank is supplied. .

  As shown in FIGS. 3A, 3 </ b> B, and 3 </ b> C, the weighing hopper 4 includes a plurality of first supply pipes P <b> 1 and second supply pipes P <b> 2, and the first supply pipe P <b> 1 and The first abrasive supply tank 2A and the second abrasive supply tank 2B may be connected to the second supply pipe P2. In this case, the air compressor 3 is connected to the first abrasive supply tank 2A via the first control valve 13A. An air compressor 3 is connected to the second abrasive supply tank 2B via a second control valve 13B. The first control valve 13A and the second control valve 13B are electrically connected so as to be controlled by the control device 12A.

  In this way, by alternately replenishing the abrasive B in the first abrasive supply tank 2A and the second abrasive supply tank 2B, from either the first supply pipe P1 or the second supply pipe P2. The abrasive B can always be supplied to the weighing hopper 4. As a result, it is possible to solve the problem that the supply is interrupted due to the shortage of the abrasive B.

  More specifically, as shown in FIG. 3A, when the abrasive B is supplied to the second abrasive supply tank 2B, the control device 12A controls the second control valve 13B to control the second abrasive. The inside of the supply tank 2B is depressurized, and the supply of the abrasive B from the second supply pipe P2 to the weighing hopper 4 is stopped. At this time, the control device 12A opens the valve of the first control valve 13A and controls the compressed air of the first air compressor 3A to be sent into the first abrasive supply tank 2A, whereby the first supply pipe P1. Since the abrasive B is supplied to the weighing hopper 4, the air pressure in the first abrasive supply tank 2A is increased.

  Then, when a sensor (not shown) attached to the first abrasive supply tank 2A detects the lower limit of the amount of abrasive B in the first abrasive supply tank 2A, the control device 12A controls the first control valve 13A. The pressure in the first abrasive supply tank 2A is controlled to reduce the supply of the abrasive B from the first supply pipe P1 to the measuring hopper 4, and the second control valve 13B is opened to supply compressed air. The abrasive B is supplied to the weighing hopper 4 from the second supply pipe P <b> 2 by controlling to feed into the 2 abrasive supply tank 2 </ b> B. As a result, the supply of the abrasive B to the weighing hopper 4 is not interrupted.

  As shown in FIGS. 3A, 3B, and 3C, when the lower limit of the amount of abrasive B in the first abrasive supply tank 2A is detected by the sensor, the controller 12A controls the first control valve 13A. The second control valve 13B is controlled, and the supply of the abrasive B from the first abrasive supply tank 2A and the first supply pipe P1 to the measuring hopper 4 is performed from the second abrasive supply tank 2B and the second supply pipe P2. To supply the abrasive B. The abrasive B is supplied into the weighing hopper 4 without interruption, and a constant amount of the abrasive B is always stored in the weighing hopper 4.

For this reason, the abrasive material supply apparatus 1 can be used by appropriately switching the abrasive material B stored in the plurality of abrasive material supply tanks without installing a switching valve.
As a result, by continuously using the first abrasive supply tank 2A and the second abrasive supply tank 2B alternately, the abrasive always containing a desired amount of the abrasive B from the abrasive nozzle 8 of the processing machine A (see FIG. 1). It is possible to continuously process by continuously jetting the jet toward the workpiece W.

It is a layout view showing an abrasive supply device and an abrasive supply method according to an embodiment of the present invention. It is an enlarged view of the X section shown in FIG. It is a figure which shows the modification of the abrasive | polishing material supply apparatus which concerns on embodiment of this invention, and an abrasive | polishing material supply method, (a) supplies an abrasive material to a measurement hopper from 1st supply piping, and is set to a 2nd abrasive material supply tank. Explanatory drawing which shows the state when replenishing abrasives, (b) is the supply amount of abrasives in the first supply pipe is the lower limit, and when the abrasive is supplied to the weighing hopper in the second supply pipe FIG. 6C is an explanatory view showing a state, and FIG. 5C is an explanatory view showing a state when the first abrasive supply tank is replenished with the abrasive and the abrasive in the second abrasive supply tank is supplied. It is a schematic sectional drawing which shows the measurement hopper of the conventional abrasives supply apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Abrasive supply apparatus 2 Abrasive supply tank 2A 1st abrasive supply tank (abrasive supply tank)
2B Second abrasive supply tank (Abrasive supply tank)
DESCRIPTION OF SYMBOLS 3 Air compressor 4 Weighing hopper 4b Discharge port 5 Needle valve 5a Valve body 5b Actuator 6 Actuator 6a Output rod 7 Funnel 8 Abrasive nozzle 8a Ultra high pressure water inlet 14 Electromagnetic on-off valve A Abrasive water jet processing machine (processing machine)
B Abrasive material H Amount of opening L Length of supply pipe P Supply pipe P1 First supply pipe (supply pipe)
P2 Second supply pipe (supply pipe)
Pa Base end Pb Tip SP Spring member T Abrasive suction tube W Workpiece θ Needle valve tip angle

Claims (3)

An abrasive supply tank comprising a pressure vessel for storing particulate abrasive;
In this abrasive supply tank, an air compressor for applying air pressure,
A supply pipe for connecting the base end to the abrasive supply tank and pumping the abrasive in the abrasive supply tank;
In an abrasive material supply apparatus comprising:
The supply pipe is suspended in the weighing hopper from above the weighing hopper whose top end is open on the upper surface , and the tip is in contact with the abrasive stored in the weighing hopper. It is installed in a state where the air pressure at the tip is attenuated to near atmospheric pressure by pressure loss so that supply is stopped,
The metering hopper includes a needle valve that opens and closes the discharge port at a discharge port formed at the bottom of the weighing hopper,
A funnel for introducing the abrasive discharged from the discharge port opened to the atmosphere into an abrasive suction tube connected to an abrasive nozzle; and
The abrasive nozzle sucks the abrasive in the funnel through the abrasive suction tube by the negative pressure of the water jet supplied to the ultra-high pressure water introduction port provided in the abrasive nozzle, and the abrasive from the nozzle An abrasive supply device for jetting an abrasive jet in which a material and ultra-high pressure water are mixed . The needle valve has a substantially rod-shaped valve body in which a tip angle of the needle valve is formed from 10 degrees to 90 degrees and an axial opening amount is moved by an actuator ;
An actuator that is actuated by an output rod provided in the actuator to open the valve body;
A spring member for closing the valve body,
2. The abrasive supply device according to claim 1, wherein the valve body and the operating portion are lowered by the spring force of the spring member and the weight of the valve body to close the discharge port . An abrasive supply method using the abrasive supply device according to claim 1 or 2,
A plurality of the supply pipes are arranged in the weighing hopper,
The abrasive supply tanks are connected to the plurality of supply pipes,
When the amount of abrasive in one of the abrasive supply tanks reaches a lower limit,
An abrasive supply method, wherein the abrasive is supplied from the other supply pipe connected to the other abrasive supply tank to the weighing hopper.

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