JPS6049572B2 - How to move objects from the decompression chamber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing objects from a vacuum chamber.

There is a need for a method for continuously moving materials from subatmospheric pressures.

Methods have been proposed to accomplish this problem, which simply involve gripping the material (hereinafter referred to as the "workpiece") and applying sufficient tension to the workpiece to pull it out of the vacuum chamber. Some early proposals involved pulling the workpiece through a vacuum seal, e.g. a rubber diaphragm; others pulled the workpiece from a vacuum chamber through an atmospheric leg around a pulley and introduced it into atmospheric pressure. All of these prior proposals are effective for some applications, where some of the workpieces cannot withstand the tension required to pull the workpiece out of the vacuum chamber. There is also.

Thermoplastic foams are examples of this type of work piece. Approximately O, 0
Pure extruded polystyrene foam of 1.5 PCF or less is extremely soft and brittle and is adversely affected by its own tension when pulled out of the vacuum. The object of the present invention is to provide a method for pulling out a workpiece from a vacuum chamber through a liquid seal only when the workpiece is lighter than the liquid and floats up when submerged in a liquid, that is, a method for moving an object from a vacuum chamber. It is in.

This unique and novel method applies tension to the workpiece and is therefore applicable to most brittle workpieces.

The basic principle of the present invention is simply that when the workpiece leaves the reduced pressure area, the workpiece is gently submerged in the liquid, and at a certain depth in the liquid, the pressure that the workpiece finally experiences becomes equal to atmospheric pressure. At this point, the work piece is released into atmospheric pressure.

It is well known that when the lower end of a pipe is immersed in water and the air at the upper end is exhausted, water is sucked up into the pipe.

The more air is evacuated, the higher the water rises until it finally stops at a height of 10.36 m, (34 feet). At this point, all the air above the water in the tube has been exhausted. Water height 10.367 TI. (3
4 feet) corresponds to atmospheric pressure. In other words, it is the atmospheric pressure that pushes water up into the pipes that causes the water level to rise. When performing the above experiment with a mercury solution, the height is 10.36n1. (
76.2 cm (30 inches) instead of 34 feet (34 feet).

This is because the specific gravity of mercury is greater than that of water. mercury column 2
．． A vacuum equal to 54 cm (1 inch) equals 34.3 columns of water.
5 cm (1.13 feet) equals 5.08 columns of mercury
cm (2 inches) is equal to 68.70 cm (2.26 feet) of water, and so on. All of the heights described in the two bar graphs above are vertical heights. Vertical height for the same degree of vacuum, depending on whether the tube is upright, inclined, or bent, large or small, or an assembly of large and small tubes. are the same. The term 1 atmosphere is often used to describe a tube that contains a liquid and maintains a reduced pressure above the liquid.

In the following, 5 atmospheres are used in the present invention. The invention will be explained with reference to the drawings. Soak work piece 1 in liquid 2.

In this case, the workpiece 1 is brought into contact with the surface of a conveyor belt 3, which is placed on the atmospheric leg 4. Processed piece 1
receives a buoyancy force 5, and this force 5 is divided into force 6 and force 7 components. Component force 6 is perpendicular to the surface of conveyor belt 3, and this force increases the friction between the belt and the work piece. The component force 7 attempts to release the work piece in the direction 8. The smaller the angle 9, the smaller the force 7 and the larger the force 6. For a certain value of the angle 9 and for angles smaller than that value, the workpiece 1 moved by the force 7 succumbs to friction and moves downward in the direction 10. If the bottom is immersed in liquid 2,
The angle 9 can be estimated by determining the coefficient of friction between the workpiece 1 and the conveyor belt 3.

The coefficient of friction is expressed as the tangent of angle 9. Selecting an angle smaller than the calculated value provides some assurance of reliable operation. It is clear from FIG. 1 that the conveyor belt 3 is driven in direction 11 by a conventional conveyor belt drive 12, preferably by a variable speed electric motor with a suitable transmission. The conveyor belt 3 should be supported in the atmospheric leg 4 by suitable means. Idler rollers 13 may be arranged along the length of the belt. The height 14 of the liquid above the liquid reservoir 15 is determined by the degree of reduced pressure within the vacuum chamber 16. This reduced pressure is obtained 7 by a vacuum pump connected to the vacuum chamber 16 via a conventional control device and a suitable orifice 17. In practice, the workpiece 1 is moved from the vacuum chamber 16,
Next, it is immersed in the liquid 2 by the action of the conveyor belt 3, moves downward along the belt through the atmospheric leg 4, enters the liquid reservoir 15, then moves upward along the belt from the liquid reservoir,
Exit the device in direction 18.

The friction between the belt 3 and the work piece 1 is equal to the thrust that causes the belt work piece to move along through the liquid 2. The work piece does not need to be a continuous body since one piece of the work piece does not affect the other pieces. In this case there is no tension pulling the workpiece. This is clear from FIG. 2, in which each piece 19 moves independently of the other pieces.
In FIG. 3, the origin of the workpiece 1 is not shown. This is because the workpiece can be introduced into the vacuum chamber 16 in various ways. One source is shown in the examples.

Friction alone is less persuasive than what users of the prior art would prefer.

Therefore, pins, sponges, spikes, blades or other protrusions 20 are secured to the conveyor belt (see FIG. 3) to ensure a stronger grip between the belt and the workpiece. Experimental Example 1 An experimental apparatus was constructed.

Atmosphere leg 4 has a diameter of 15.24 cm (6 inches) and a length of 40
．． The aluminum pipe 6 was 8rrL (136 feet). Since there was no room in the atmospheric leg for a suitable idler roller, a supported conveyor belt was constructed as shown in FIG. Idler rollers were used for belt support beyond the end of the atmospheric leg. The support member 21 is an aluminum plate bent into a triangular shape and inserted into the atmospheric leg 22 having a diameter of 15.24 cm (6 inches).
Tighten in place with bolts 23 along the length of the atmospheric leg (see Figure 4). The cross-sectional view of FIG. 4 shows the conveyor belt 24 towards the vacuum chamber and the belt 25 towards the sump, both showing a cross-section of the work piece 26 floating and crimped on the belt and moving towards the sump.

The atmospheric legs of the experimental apparatus were tilted at an angle of 14 and 28" from the horizontal. The conveyor belt was a 10.16 cm (4 in.) wide polypropylene fabric, with a variable speed of 314 hp via a suitable gear reducer. Driven by a motor.
A plastic extrusion die is placed inside the vacuum chamber in the feed channel or adapter and the atmospheric leg is passed through the die at the end of the vacuum chamber opposite the clamped end. Any material or workpiece exiting the die passes through the vacuum chamber, impinges on the conveyor belt, and begins its journey through the atmospheric leg. A small conventional extruder is secured to a die adapter and commercial polyethylene expandable pellets are fed into the extruder hopper. The foam that comes out of the die has a temperature of 0.0 when it is extruded into the atmosphere.
053k91c71 (3.3F) CF). However, if the air in the room is partially exhausted, the density becomes 0.029k91.
d (·1.8 PCF), and as described later, the foam was continuously exposed by descending through the atmospheric leg. EXPERIMENTAL EXAMPLE ■ The liquid used in almost all operations of the experimental apparatus described in Experimental Example 1 was plain water.

Therefore, this experiment was intended to see if the same method could be used with other liquids. The solution was made up of 57% sucrose and 43% water. The specific gravity of the solution was 1.27. That is, it is 27% heavier than regular water. Expandable pellets were fed into an extruder. The density of polystyrene foam when extruded into the atmosphere is 0.086k91
It became cT1 (5.4 PCF). But mercury 48.
When extruded into a 26 cm (19 inch) vacuum, the density drops to 0.04 k91 cT1 (2.5 PCF). The results were the same whether the liquid was ordinary water or a sucrose solution with a high specific gravity. EXPERIMENTAL EXAMPLE ■ Other thermoplastic materials are selected to demonstrate that the present invention also reduces the density of various plastic foams.

Commercially available expandable polystyrene pellets were used in Experimental Examples 1 and 2. In this experiment, commercially available chain-shaped polyethylene pellets were mixed with a number of commercially available strong chemical blowing agents. This mixture is fed to the extruder hopper. The density of the foam that comes out of the die when extruded into the atmosphere is 0.656k91d (4
1 PCF). However, the column of mercury is 68.58 cm (2
The density of the polyethylene foam revealed by extruding into a vacuum of 0.197k91cI1 (12.3P
CF). In Experimental Example 1, ■ and ■, the feed material for the extruder was used, and the foam material was mixed into the feed material,
Impregnated into or added to plastic. Another series of tests were selected to look at other methods of adding blowing agents. Commercially available polystyrene pellets are fed into the extruder hopper and liquid blowing agent is injected into the extruder body using known commercially practiced methods. For each combination of polystyrene and liquid blowing agent, the density developed through a vacuum chamber using the experimental apparatus described in Example 1 is considerably lower than that obtained in conventional atmospheric extrusion.
A nominal density of 0.016k91a1 (1.0 PCF) is often found, which is lower than any practical extruded polystyrene density mentioned above. What has been described above is merely a few examples of the present invention, and it goes without saying that various changes can be made within the scope of the claims.

[Brief explanation of the drawing]

l Figure 1 is a diagram of an apparatus implementing the method of the invention for moving objects from a vacuum chamber; Figure 2 is a partial diagram of the atmospheric leg of Figure 1 showing the individual parts moving along the conveyor; Figure 3 is a diagrammatic view of seven other embodiments of the invention showing protrusions on the conveyor to increase the force of the conveyor on an object; Figure 4 is a cross-sectional view of an experimental setup using the conveyor in an atmospheric limb; It is. 1, 26... Processed piece, 2... Liquid, 3, 24, 25.
・Conveyor belt, 4, 22... Atmospheric leg, 5... Buoyancy, 6, 7... Component force, 12... Conveyor belt drive unit, 13... Idler roller, 14... height, 15...liquid reservoir, 16...vacuum chamber, 17...orifice, 20...protrusion, 21...support member, 23...
··bolt.

Claims (1)

[Claims] 1. A vacuum chamber having an evacuation means in a method for transferring and introducing a workpiece into atmospheric pressure from a place with a pressure below atmospheric pressure;
an atmospheric leg connected to the vacuum chamber and having an end disposed in a liquid reservoir, the density of the workpiece being lower than the density of the liquid;
A conveyor is disposed within the atmospheric leg and extends from the vacuum chamber to the sump to move the workpiece from the vacuum chamber to the sump, thereby causing the workpiece to float. A method for moving an object from a vacuum chamber, characterized in that the object is moved up and engaged with the conveyor, and the work piece is passed through the liquid reservoir together with the conveyor and introduced into the atmospheric pressure. 2. Friction between the workpiece and the conveyor is configured to make the conveyor at an acute angle to the horizontal sufficient to cause the workpiece to move along the conveyor and pass through the sump. A method for moving an object from a reduced pressure chamber according to claim 1. 3. A patent characterized in that the conveyor is provided with a protrusion, and the protrusion abuts against the workpiece, thereby causing the workpiece to pass together with the conveyor into the liquid reservoir and releasing the workpiece into the atmosphere. A method for moving an object from a reduced pressure chamber according to claim 1.