Energy Absorber For High Pressure Fluid Jets

Abstract

A device is disclosed for absorbing the energy of a fluid cutting jet after it has passed through the workpiece in order to reduce the sound level as well as the spray and vapor normally accompanying the fluid jet cutting process. The device includes a baffle arrangement disposed immediately adjacent the workpiece and enclosed in a housing to receive and contain the jet after it has passed through the workpiece so as to prevent the sonic energy and spray from emanating into the surrounding environment. The jet itself is directed through the baffle arrangement to impact a liquid bath, backed up with a hardened steel block, thereby dissipating its momentum.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention concerns devices for the absorption of the energy of a high pressure jet discharging into the atmosphere, and more particularly such jets used in fluid jet cutting processes.

2. Description of the Prior Art

Fluid jet cutting systems have been proposed in the past and have been demonstrated to be highly effective for certain applications. In these systems, a fluid such as water is discharged through a nozzle at extremely high pressures ranging from 10,000 to 100,000 psi to impact a workpiece and shear it by the high kinetic energy of the jet. In such systems, the process is normally carried out in the open, and the extremely high jet velocities (may be on the order of 3,000 ft/sec) can cause noise levels to reach 140 decibels in the immediate vicinity of the jet. This level intensity must be regarded as highly undesirable and contrary to the interests of operator comfort and efficiency.

In addition, the high energy of the jet must be somehow absorbed to minimize the danger of accidental impacting of the jet with persons or equipment, and the fluid itself collected for disposal.

Prior art systems are disclosed in U.S. Pat. Nos. 3,212,378 and 2,985,050 have attempted to meet these latter needs by the use of a disposal tank containing a liquid bath, which may be backed up by a resilient cushion to absorb the jet energy.

The resilient cushion, however, is likely to be a high maintenance item as it is very easily degraded by the jet action, and none of the prior art systems provides for the former problem, i.e., the noise created by the jet.

Therefore, it is an object of the present invention to provide an energy absorber for such a fluid jet which substantially reduces the noise level associated therewith and does not involve excessive maintenance of its component parts.

SUMMARY OF THE INVENTION

This and other objects which will become apparent upon a reading of the following specification and claims are accomplished by providing a baffle arrangement contained in a housing enclosing the jet immediately upon its exit from the workpiece area and impacting the jet upon a liquid bath backed up by a hardened steel block.

DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view of an energy absorber according to the present invention.

FIG. 2 is a sectional view of an alternate embodiment of the energy absorber according to the present invention.

DETAILED DESCRIPTION

In the following detailed description, certain specific terminology will be utilized for the sake of clarity and specific embodiments will be described in order to provide a complete understanding of the invention, but it is to be understood that the invention is not so limited and may be practiced in a variety of forms and embodiments.

Referring to the drawing and particularly FIG. 1, a nozzle tip 10 is depicted disposed to direct a jet 12 of a liquid such as water against a workpiece 14 which is moved past the jet 12 to produce a cutting action thereon. After passing through the workpiece 14, the jet is directed via opening 16 in the workpiece support 18 to the energy absorber 20 disposed immediately proximate to the exit point of the jet 12.

The energy absorber 20 includes a housing 22 supported on a base 24 and closed at one end by means of a top plate 26 retained by an end cap 28. The top plate 26 has an opening 30 formed therein to allow the jet 12 to pass into the housing cavity 32 while reducing the volume of material removed from the workpiece to be carried thereinto.

Disposed within the uppermost region of the housing cavity 32 is a baffling arrangement consisting of a volume of a resilient material 34 such as foam rubber having a passage 36 formed therein by the initial action of the fluid jet and retained in a holder 38 also having an opening 40 formed therein, with opening 40 being aligned with the jet 12 to allow it to pass therethrough.

The volume of resilient material 34 functions to prevent the emanation of spray and sonic energy from the interior of the absorber into the surrounding environs so as to drastically reduce the noise level accompanying the operation of the device.

The jet 12 then passes into an open space 42, then into a space 44 containing a liquid such as water where a portion of its energy is absorbed, and finally impacts a hardened steel impact block disposed at the bottom of space 44 which absorbs the residual energy of the jet 12.

The overflow created by the liquid which forms the jet 12 is disposed of via vent and overflow outlet 48 which leads to a drain.

The passage of the jet through the volume of water in space 44 functions to further reduce the noise level as the Mach number of the jet is greatly reduced in water, and its kinetic energy is also considerably reduced by friction and fluid entrainment before impacting the hardened steel impact block 44 to lessen the erosive effect the jet 12 may have thereon.

The impact block 44 may be of other suitably hard material capable of resisting the erosive action of the jet such as tungsten carbide.

The impact block 44 may be replaced as may also the volume of resilient material if erosive wear has been substantial.

As the jet 12 is totally contained after entering the energy absorber 20, it can be appreciated that sound, spray, and vapor are greatly reduced by its use.

A second embodiment is depicted in FIG. 2, and is substantially the same as that depicted in FIG. 1 with the exception of the baffling arrangement which in this embodiment consists of a series of frusto-conical baffle plates 50 with respect to back spray of the jet, having openings 52 disposed in the holder 38 and positioned by means of spacers 54. It has been found that the reversely sloping orientation of the baffle plates 50 prevents sound, spray, and vapor from passing back out the entrance opening 30 as these tend to be trapped thereby and confined in the housing 22, while eliminating any need to service the device, as no significant erosion of the frusto-conical baffle plates 50 normally occurs during reasonable maintenance intervals.

From the above description, it can be appreciated that the usefulness of the jet cutting systems can be substantially enhanced by the use of the energy absorber according to the present invention, and that this device is simple and relatively inexpensive to fabricate.

Many variations are of course possible within the scope of this invention.

Claims

What is claimed is:

1. An energy absorber for receiving a high velocity jet of liquid comprising:

a housing disposed to receive said high velocity jet and substantially enclose it;

means within said housing to absorb said high velocity fluid jet energy, including baffle means surrounding said fluid jet after it enters said housing and preventing sound and spray from passing back out of said housing, comprising a volume of resilient material having a passage therethrough to receive said jet whereby sound and spray from said jet is substantially prevented from passing into the surrounding environment.

2. The absorber of claim 1 wherein said means to absorb said fluid jet energy includes a liquid bath disposed to be impacted by said fluid jet.

3. The absorber of claim 2 wherein said means to absorb said fluid jet energy further includes a block in said liquid bath disposed to be impacted by said fluid jet after passing through said liquid bath.

4. In a system for fluid jet cutting wherein a high velocity jet is directed at a workpiece to sever the same, the improvement comprising:

energy absorbing means including a housing disposed to receive and substantially contain said fluid jet immediately after passing through said workpiece and also including means in said housing to absorb the energy of said fluid jet including baffle means surrounding said fluid jet after it enters said housing and preventing sound and spray from passing back out of said housing, comprising a volume of resilient material having a passage therethrough to receive said jet.

5. The system of claim 4 wherein said means to absorb said fluid jet energy includes a liquid bath disposed to be impacted by said fluid jet.

6. The system of claim 5 wherein said means to absorb said fluid jet energy further includes a block in said liquid bath disposed to be impacted by said fluid jet after passing through said liquid bath.

7. An energy absorber for receiving a high velocity jet of liquid comprising:

a housing disposed to receive said high velocity jet and substantially enclose it;

means within said housing to absorb said high velocity jet energy, including baffle means surrounding said fluid jet after it enters said housing and preventing sound and spray from passing back out of said housing, comprising a plurality of baffle plates each having an opening aligned with each other to receive said jet.

8. The absorber of claim 7 wherein said means to absorb said fluid jet energy includes a liquid bath disposed to be impacted by said fluid jet.

9. The absorber of claim 8 wherein said means to absorb said fluid jet energy further includes a block in said liquid bath disposed to be impacted by said fluid jet after passing through said liquid bath.

10. In a system for fluid jet cutting wherein a high velocity jet is directed at a workpiece to sever the same, the improvement comprising:

energy absorbing means including a housing disposed to receive and substantially contain said fluid jet immediately after passing through said workpiece and also including means in said housing to absorb the energy of said fluid jet including baffle means surrounding said fluid jet after it enters said housing and preventing sound and spray from passing back out of said housing, comprising a plurality of baffle plates each having an opening aligned with each other to receive said jet.

11. The system of claim 10 wherein said means to absorb said fluid jet energy includes a liquid bath disposed to be impacted by said fluid jet.

12. The system of claim 11 wherein said means to absorb said fluid jet energy further includes a block in said liquid bath disposed to be impacted by said fluid jet after passing through said liquid bath.

13. The system of claim 10 wherein said series of baffle plates slope reversely with respect to the direction of back spray from said jet.

14. The system of claim 13 wherein said reversely sloping series of baffle plates are frusto-conical in shape.