JPS6347099A - Liquid jet device and method of cutting, corroding and fractionizing solid material by using said device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention uses a high-speed liquid jet to cut materials,
This invention relates to a liquid jet device that utilizes cavitation phenomena to facilitate corrosion or fragmentation.

This technique relies on the creation of vapor cavities in the jet liquid. This vapor cavity annihilates or implodes at a location on or adjacent to the material to be processed, providing a powerful localized shock wave that helps break up the material to be removed from the non-workpiece. In any operating system, it must be ensured, firstly, that cavities are created and, secondly, that they disappear or are concentrated in the desired processing area.

The current state of this technology is U.S. Patent No. 4,193,635 (
Thiruvengadam et al.) and U.S. Pat. No. 4,389,071
(Johnson Jr. et al.). As these patent studies demonstrate, two main techniques have been employed, either independently or in combination, to induce cavities in liquid jets. The first technique uses a specially shaped jet nozzle to generate a vortex that induces a cavity. This effect could probably be enhanced by exploiting resonance phenomena in the nozzle structure. This approach is typified by the above-mentioned Sihanson patent and the same inventor's earlier patents.

By surrounding the emerging jet with liquid that has relatively little movement, it is helped to maintain the cavity until the machining φ region is reached, and the shearing effect between the jet and the surrounding liquid promotes the hollowing effect. It is allowed to be done. Such shear effects are the basis of the second major technique used to induce cavities in liquid jets, which are described in detail in the Thiruvengatam et al. patent. Briefly, this argument can be summarized as follows.

Cavities occur when a very high velocity liquid jet is fired through a relatively still liquid.

Cavities result from spinning vortices of free liquid surrounding a jet moving at extremely high speeds. The interior of the vortex, due to centrifugal forces, is largely below the vapor pressure of the liquid, thus forming bubbles or cavities, which are usually carried downstream by the momentum of the high-velocity jet. Some distance downstream from the beginning, the bubble disappears, generating a very large temporary energy. If this annihilation occurs at or near the target, damage to the target structure can occur.

The present invention relates to a device that utilizes such shear-induced cavities.

As is clear from the above literature, the distance between the jet nozzle and the target is quite important. In addition, it is understood that the target itself is basically based on utilizing the liquid shearing effect when operated in a position submerged in liquid. It will be. Both of these problems are noted in the prior art and are typical of the solutions proposed by Thiruvengatam et al.

Thus, in FIG. 8, Thirubengatam discloses a flexible shroud that is supplied with water via a tube 152. The depth of the water in the shroud is an overflow orifice! 53. Water from the jets and external sources escapes between the shroud and the pressurized object (and apparently through the workpiece in the illustrated embodiment). It has also been proposed to provide a stage of sensors to sense the position of the target and control the position of the jet nozzle accordingly.

One valuable and common use of equipment of the kind described above is to
One can mention the fragmentation of rocks during mineral extraction operations. It is clear that any mechanism that comes into contact with the rock during such operations is subject to considerable wear and tear.

Difficult processing environments and irregular, abrasive targets are also typical of many other possible applications. The arrangement as shown in Dilubengadam is unlikely to be sufficient for such an application. Additionally, rough and irregular surfaces, such as rocks, provide large amounts of water to the shroud, while increasing the water pressure in the shroud due to varying leakage rates between the shroud and the rock. It is difficult to keep the enclosure filled with water at the risk of change.

U.S. Pat. No. 4,343,475 (Vicars) discloses the use of rigidly constructed shrouds to enclose low pressure water streams to provide artificial submergence of hollowed jets. However, in a paper submitted at the 5th International Symposium on Jet Cutting Technology held in Hanover, West Germany from June 211 to 4, 1980, the inventor and co-authors stated, "Tubular shrouds do not improve cavitation and have the distinct disadvantages of requiring active surface contact and increasing the backlash to the operator." The shroud in this case had an opening or adjacent to the target to allow water to escape.

It should be noted that the Vicars patent and the Vicars et al. paper relate to hollow jet technology of the type where the hollowing is induced by the shape of the jet nozzle.

U.S. Patent No. 4,124,162 (Shwara) also
Discloses the use of a "shroud" around the high speed liquid cutting sheller 1. One function of this shroud appears to be to induce a cavity in the jet 1 by acting as an expansion chamber. And the dimensions of the shroud are obviously of considerable importance.

This is because the jet must expand significantly to negotiate the walls of the distillation at the open end, creating a vacuum in the remainder of the shroud space.

Thus, the shroud can more accurately be considered to form part of the nozzle assembly, with the effective jet orifice being at the downstream end of the shroud. This downstream end is spaced away from the target surface to optimize cutting effectiveness.

Quite surprisingly in view of the teachings of Vicars and Schwara, I have found that if certain conditions are met, a rigid shroud defining a chamber that contacts the workpiece and encloses Shella 1. We have discovered that it is possible to construct a highly effective hollow jet device by using the following method.

According to my invention, there is provided a body defining a wall of a hollowing chamber having one end facing the working surface, the body defining a wall of the hollowing chamber, the body defining the wall of the hollowing chamber having one end extending to the right of the working surface; a source of high-pressure liquid connected to the source and supported opposite the open end of the hollowed chamber, the high-pressure liquid being ejected from the nozzle away from the annular region; a jet nozzle oriented at one end to impact two surfaces in the hollowed-out region; and at least one outlet located in the wall of the hollowed chamber at a distance from the open end. an opening, the flow capacity of which is greater than the leakage between the annular region and the working surface, such that it does not create a pressure of sufficient magnitude to suppress the cavities in the hollowing chamber; 1" large enough to be able to compensate for the liquid in the hollow chamber, and small enough to hold enough liquid to submerge the liquid jet; The pressure of the high-pressure liquid source, the dimensions of the jet nozzle, and the distance between the nozzle and the open end of the hollowing chamber are such that the shear or hollowing vortex between the liquid jet and the liquid held in the hollowing chamber is controlled. A liquid jet device is provided which is applied to the work surface to be treated and is retained until it induces and impacts the work surface.

These and further features of the invention will be understood from the following description of preferred embodiments with reference to the drawings.

The drawing shows the distal portion of the impact tool T of the invention in contact with the shoulder surface R. The tool forms a hammer with a mallet head and is shown as a cylindrical forest with a front surface 2 having a substantial area.

The front surface 2 is held against the shoulder surface R and is repeatedly impacted by a mechanism not shown and which does not itself form part of the invention. The front surface 2 contacts the shoulder surface R in an annular region surrounding a cylindrical hollow chamber 4 formed coaxially with the bar in its center. The tool T includes a connection member 10 to a high-pressure water supply source 12.
and a nozzle 14 screwed into a hole coaxially drilled with the rod on the side opposite to the opening side of the hollowed chamber at the position of the shoulder surface R. Or is provided.

The nozzle 14 is shaped and directed so that a jet of high pressure liquid emitted therefrom impinges on the shoulder surface in a region remote from the annular region of the front surface 2 in contact with the shoulder surface. One or more further cut holes 16 (two shown) forming openings in the wall of the hollow chamber 4 are provided at positions remote from the open end of the hollow chamber. The dimensions of this opening are such that it is possible to avoid building up excessive pressure or to keep the cavity filled with water so that the jet from the nozzle 14 is submerged from the chamber. It is set so that the water can be seen through. Nozzle 1
4 and the cut hole 16 are sufficiently small compared to the leakage between the front surface 2 and the shoulder surface R or the flow rate through the cut hole 16 under the normal operating environment, so that the pressure in the chamber 4 is The dominant factor determining the flow rate of the hole 16 is chosen to be. The pressure and capacity of the source 12 is relative to the nozzle 14;
The shear between the liquid jet and the liquid held in the chamber is chosen such that a cavity vortex is induced and maintained until it impacts the work surface.

The invention need not be embodied in an impact device such as a hammer, but could also be incorporated into a non-impact tool, or a liquid jet in a body having an annular contact area in contact with the work surface to be treated. It is a feature of the invention that a hollow chamber is defined and that the body is as rigid as necessary to withstand the wear and tear to which it is exposed. It is not necessary that the space between the main body and the processed surface be watertight, nor that water can escape from this space. This is because the opening 16 is
This is because it becomes the main route for water to escape from the room. The body or tool must be held close enough to the work surface so that the distance between the nozzle 14 and the work surface is maintained accurately.

When dimensioning the aperture 16, it should be borne in mind that a certain pressure increase in the chamber 4 is advantageous to increase the intensity of the cavitation phenomenon. To induce a cavity, the local pressure in the induced vortex must be lower than the vapor pressure of water, which is extremely small at room temperature. If the pressure in chamber 4 is close to atmospheric pressure, the maximum local pressure drop in the vortex is about 1 atmosphere. However, because
If the pressure in chamber 4 were approximately 2 atmospheres, the maximum local pressure drop in the chamber would be doubled and the intensity of cavitation would increase. A higher jet velocity is of course required to induce a cavity, but this can be easily obtained if the pressure increase in the chamber is less than 2.3 atmospheres. In any case, this pressure is much smaller compared to the pressure of the liquid supplied to the nozzle 14. Supply pressure is usually 200
The pressure ranges from 800 atmospheres to 800 atmospheres, but more or less can be used as long as the required cavity is obtained.

For testing purposes, a device similar to that shown in cross section was constructed. This device has a circular end face and a maximum diameter of 15 cm.
It was m. The diameter of cutting holes 6 and 8 is 13111 [11
Met. The diameter of chamber 4 was 19 IDl] and its length was 7.5 cm. The nozzle was a simple threaded plastic with two orifices. The diameter of the four openings 16 was 6.35111 m and their outer ends were threaded to accommodate removable plugs. These intersected the chamber at 25n+n+ from the nozzle.

In order to investigate the effect of the drainage holes, the test device was installed with a thickness of about 7.5
A concrete aggregate slab of 2 cm was tested.

Water was supplied at a flow rate of 90 liters/min by a bositeif displacement pump constituting the supply source 12, and its maximum pressure was approximately 7 MPa. 3 when opening 16 is open
In this experiment, a hole was drilled through the concrete within 3 seconds after the pressure reached approximately 40 QKPa. When the same experiment was performed three times with opening 16 closed, it took 45 to 90 seconds to drill the same hole.

In further testing, the device is rotated and placed over the target material;
A good interfacial force between the target and the device was observed. The water supply pressure is 6.9 MPa, and the supply rate is 113.
It cost 65 ritsu and 1 hel. The time required to penetrate the target material was recorded on each of the following five trials.

Test 1: All four openings [16] were completed. Penetration time is 1
．． It was 5 seconds.

Test 2: One opening was closed. Penetration time was between 2 and 1 and 3 seconds.

Test 3: Open [1 closed twice. Penetration time was 9 seconds.

Test 4: Three openings were closed. The penetration time was 11 seconds.

Test 5: All four openings were closed. The penetration time was 30 seconds.

A further comparative test was conducted without a shroud surrounding the nozzle at a distance of 7.5 cm from the target. - Tested at the same pressure and flow rate as described. The Force 5 hole, which was activated for several minutes, did not open at all.

It can be seen that an excessive increase in pressure of waste and used water in the room has a negative effect on the formation of cavities.

In addition to the test described in item 1, this device was used at a spraying rate of approximately 2,700 joules of energy and a spraying frequency of 12 joules per minute.
I was able to use the water impact machine 0 times. The water pressure was about 7 to 81 Pa, and the flow rate was about 80 minutes per minute.

Attach the impact machine to the carrier (J, using this device,
A hard shoulder surface measuring approximately 4 meters x 6 meters was cut with scattered nickel ore. When the impact was applied continuously for about 5 minutes, about 800 kg of pickpockets were produced. A control test without water yielded only debris and dust, but no abrasions.

The water pressure and flow rate, the equipment and the dimensions of the chamber, nozzle and cutting hole, the distance of the nozzle from the open end of the chamber will vary depending on the material to be treated. Of course, the pressure, flow rate and velocity of the water jet are related to each other. As the pressure increases, the velocity and flow rate of the water jet also generally increases. The liquid used does not necessarily have to be water, or will probably be the cheapest and most convenient liquid to use. When using liquids other than water, to achieve the desired effect,
It may be necessary to change operating parameters. Additionally, the exact location and shape of the apertures 16 and other outlets, rings and nozzles are not critical, but may be advantageously optimized based on experience.

[Brief explanation of drawings]

The drawing shows a longitudinal section of the device of the invention. T... Main body, R... Shoulder surface, 4... Hollowing chamber, 12
...Source of supply, 14...Nozzle, 16...Opening: B applicant's agent Masuri Suzue Takehiko

Claims (5)

[Claims] (1) A liquid jet device applied to an untreated processed surface, comprising a high-pressure liquid supply source, a jet nozzle connected to the supply source, and a main body that supports the jet nozzle with respect to the processed surface, The main body (T) defines the wall of a hollowing chamber (4) having an open end facing the working surface, and the working surface in an annular region surrounding the open side of the hollowing chamber (4). said jet nozzle (14) is supported opposite the open end of the hollowed chamber, and the high pressure liquid ejected from said jet nozzle is in an area remote from said annular area. at least one discharge opening (16) directed towards the open end so as to impact the working surface and provided in the wall of the hollowed chamber at a distance from the open end, the flow volume of which is is greater than the leakage between the annular region and the working surface, and evacuates the liquid in the hollowing chamber such that the liquid in the hollowing chamber does not create a pressure of sufficient magnitude to suppress the cavity in the hollowing chamber. the pressure of the high-pressure liquid source (12) and the jet nozzle. The dimensions and the distance between the nozzle and the open end of the cavitation chamber are such that this occurs until the shear between the liquid jet and the liquid held in the cavity induces a cavitation vortex and impacts the machined surface. A liquid jet device characterized in that it is retained. (2) The main body (T) is the end part of the rod, and the hollow chamber (4
) consists of a cylindrical hole extending coaxially from its end, a jet nozzle (14) is located at the inner end of the hollowed chamber coaxial with said rod, and said discharge hole (16) is located at the inner end of said rod. 2. Device according to claim 1, characterized in that it is formed by a cut hole extending between the longitudinal surface and the cylindrical hole. (3) The pressure of the liquid supply source is about 200 to about 800 atmospheres, as claimed in claim 1 or 2.
Apparatus described in section. (4) a body shaped to contact the machining surface in an annular region defining a wall of the cavity having an open end facing the machining surface and surrounding the open side of the cavity; , in close contact with the working surface of the material to be processed, and in which the high-pressure liquid supported opposite the open end of the hollowing chamber and ejected therefrom is in an area remote from said annular area. supplying a high-pressure liquid to a jet nozzle directed at an open end to impact a surface, and from at least one discharge opening provided in a wall of the hollowing chamber at a location remote from the open end; The liquid in the hollowing chamber is such that its flow rate is greater than the leakage between said annular region and the working surface and does not create a pressure of sufficient magnitude to suppress the cavities in the hollowing chamber. evacuation of the liquid in the hollowed chamber so as to be large enough to allow the liquid to be ejected and small enough to hold a sufficient amount of liquid to submerge the liquid jet; The pressure of the high-pressure liquid is maintained at a sufficient level relative to the dimensions of the jet nozzle and the distance between the jet nozzle and the open end of the hollowing chamber, such that the pressure between the liquid jet and the liquid held in the hollowing chamber is A method for cutting, eroding and fragmenting solid materials, characterized in that a hollow vortex is induced by shear forces and maintained until it impacts the work surface. (5) The method according to claim 4, wherein the pressure of the high-pressure liquid is 200 to 800 atmospheres.