JPH0116600B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a press machine in which an annular inflatable chamber is housed in a rigid external tubular body, the central space being surrounded by the inflatable chamber in a contracted state. The present invention relates to a press having an expandable chamber intended to exert a substantial radial pressure along the entire length of the expandable chamber on any object that may be inserted into the chamber.

[Conventional technology and problems]

It is a cylindrical sleeve-shaped expandable chamber made of an elastic stretchable material such as an elastomer, and is depressurized and contracted before inserting the object to be compressed (hereinafter referred to as the object to be compressed), and then pressurized. Press machines of the type having an expandable chamber that expands to compress an object to be compressed are already known. The annular inner wall of the expandable chamber is in direct contact with the compressed body.

During the compression process, the outer diameter of the compressed body usually decreases. In other words, the higher the pressure inside the expandable chamber, the more the diameter of the compressed body will shrink.
The annular inner wall of the expandable chamber must have a corresponding reduction in circumference or length in order to be able to follow the change in size of the compressed body pushed in by the pressure.

In fact, the annular inner wall accommodates the decrease in diameter of the compressed body by forming a number of wrinkles that increase in size with increasing compression.

These wrinkles are due to the weakness and premature deterioration of the material that makes up the inflatable chamber. It has been found that a significant compressive effect is exerted on the material at the bottom of the wrinkles and can induce rupture of the material due to the crushing effect. On the contrary, the sides of the wrinkles, especially the sides of the wrinkles in the near chamber of the compressed body, are stretched, and the stretch is 50% accordingly.
can even exceed the elastic limit of the elastomer (elastic material). (400% to 500%) Furthermore, during compression, the pressure stress exerted on the compressed body in these wrinkled areas, which constantly grow in size, is caused by the wall surface of the expandable chamber being compressed flat against the compressed body. is not equal to the pressure stress exerted on the compressed body in the area.

The main object of the present invention is to provide a press machine having an annular expandable chamber made of an elastomer, which expands against an object to be compressed and which does not form wrinkles when the size of the object to be compressed is reduced by pressure. An object of the present invention is to provide a press machine having an annular expandable chamber with an inner wall.

[Means for solving problems]

According to the invention, this object is achieved by a press having a rigid outer tubular support and an annular elastomer expandable chamber with an outer wall pressable against the support and an inner wall for pressing the object to be compressed, The outer wall of the inflatable chamber substantially acts on the inner surface of the tubular support, and the inner wall of the inflatable chamber compresses the object to be compressed, so that the pressure in the inflatable chamber is at the maximum compression pressure. The circumference of the inner wall is achieved by means of a press that is 1 to 0.85 times the circumference when the pressure of the expandable chamber is approximately equal to the pressure of the surrounding medium.

For convenience of explanation, the diameter of the compressed object before compression is DO,
Assuming that the diameter at the end of compression is DP, the inner diameter DGO of the expandable chamber in a state in which it freely communicates with the outside air is equal to DGO at the end of compression.
Assuming that it equals a value between 0.850DGO,
It is preferred to adopt a value equal to approximately 0.90DGO.

Preferably, the outer wall of the inflatable chamber is held in a permanent press against a rigid external support by means of a fixed connection. That is, once the inflatable chamber is evacuated, its inner wall is brought against the outer wall. The expandable chamber has a radial thickness which can then be estimated at most at 20 mm;
This value is given by the respective thickness of the two superimposed walls and the thickness of the connecting means, which properties vary considerably. The inflatable chamber diameter DGV when there is no air in the inflatable chamber is:
When there is no air inside, it is larger than the outer diameter DO of the compressible body to leave a radial gap that facilitates the insertion of the compressible body into the expandable chamber. However, this gap should be as small as possible to minimize the dead stroke of the inflatable chamber wall before contacting the compressed body. Generally, the expandable chamber diameter (DGV) during exhaust and the outer diameter (DO) of the compressed body have a relationship of DGV=1.015 to 1.035DO.

The object to be compressed is never compressed to a diameter of zero. In many cases, the diameter DP at the end of compression is the diameter before compression.
Numerous observations have shown that it is approximately equal to 80% of the DO.

Therefore, the inflatable chamber diameter is the DGV when evacuated.
value (DGV≦1.035DO) and DGO at the end of compression
Varies between values. In addition, DGO is equal to DP or cannot be less than 0.85DP, and is 0.85×
0.80DO<DP=0.80DO), that is, 0.68DO is the minimum value.

Furthermore, since the diameter of the inner wall at the end of compression matches the diameter when no pressure is applied inside the expandable chamber or when there is no vacuum, this inner wall has a connecting means that presses against the outer wall of the expandable chamber, and a connecting means that presses against the outer wall of the expandable chamber, and a It is observed that the DGV value (0.80DO) is stretched between the DGV value (0.80DO) and the 1.035DO value due to the combined effect of the negative pressure set at . This elongation can be easily demonstrated to be approximately 30%. Generally, elastomers have an elongation of 50%.
It is known that it functions as a sufficiently elastic body when it is not more than this.

Thus, a press using a fixed connection means to hold the permanently pressed outer wall of the inflatable chamber toward an external support can be used without forming wrinkles or overstretching the inner wall of the inflatable chamber. Satisfies all necessary conditions for regularly and uniformly compressing the object to be compressed.

In addition, it is desirable that the outer wall of the inflatable chamber be in a stretched state when compressed and held against the external support.

Any suitable means may be used as a connection between the inflatable chamber outer wall and the fixed external support, provided it maintains the airtightness of the inflatable chamber and does not place undue stress on the outer wall. For example, the connection may be chemical in nature by adhering the elastomer to the surface of a support, preferably made of metal. The connection may also be mechanical in nature by fixing planar parts to the outer wall of the inflatable chamber and to the support.

In one embodiment of the invention, a plurality of consecutive plates are mounted in a spaced apart array within the inflatable chamber and extend in an axial direction of the inflatable chamber. It should be noted that at least one centering rod is fixed to each plate which passes in a gas-tight manner through the outer wall of the inflatable chamber and freely passes through a corresponding hole in the external support. On the outside of the support, traction and locking means serve to pull said corresponding plate towards the support until the corresponding plate firmly forces and holds the outer wall of the inflatable chamber towards the inner surface of the support. (e.g. a nut) is attached to each center rod.

Preferably, each plate is laterally curved with a radius of curvature equal to or greater than the radius of curvature of the inner surface of the support to ensure proper action of the outer wall of the inflatable chamber toward the support.

Preferred embodiments of the invention are described below without limiting the content thereof and without excluding variant embodiments. Reference numbers refer to the accompanying drawings.

〔Example〕

The press according to the invention has a rigid tubular external support 1
If the object to be compressed (hereinafter referred to as the object to be compressed) is cylindrical, it has a cylindrical shape with an inner diameter D. Inside this support 1 there is an inflatable chamber 2 made of an elastic material of the elastomer type (natural rubber, synthetic rubber, polyurethane, silicone, etc.).
In the free state, the inflatable chamber 2 has the appearance of a cylindrical annular sleeve with a cylindrical outer wall 3 and a cylindrical inner wall 4, as seen in FIG. Its diameter is smaller than the inner diameter D of the external support 1. The external support 1 and the expandable chamber 2 have a length approximately equal to the length of the compressed body C, as seen in FIG. The inner volume 5 of the inflatable chamber 2 is placed in communication with the outside and allows expansion and deflation by means of a lower pipe 6 which passes through the support 1 through a corresponding opening 7. If pressurized gas is used in the expandable chamber 2, the pipe 6 would be sufficient. However, in consideration of safety, it is preferable to use liquid under pressure to inflate the expandable chamber, in which case an air vent pipe 8 is formed at the top of the expandable chamber 2. An air vent pipe 8 also passes through the support 1.

The plates 9 are arranged in the inner volume 5 of the inflatable chamber 2 so as to be continuous around the periphery, and each plate 9 extends over the entire length of the inflatable chamber 2. The number of plates 9 depends on the inflatable chamber diameter. In reality, a size of 100 millimeters (mm) in the circumferential direction is appropriate. A tension rod 10 is provided in the middle of each plate 9 and extends sealingly through the outer wall 3 of the inflatable chamber 2 and freely through the external support 1 through a corresponding hole 11 of suitable size. Each tension rod 10 is threaded and by screwing a nut against the outer surface of the support 1 a controllable traction force can be imposed on the rod 10.

The lower pipe 6 and the upper air vent pipe 8 are each fixed to a corresponding plate 9 inside the inflatable chamber 2 and operate in the same manner as the rod 10. Note that these pipes are installed in the same manner as the valve body, which is connected to the inner tube through the metal rim of the bicycle wheel.

If the plates 9 are very long or insufficiently rigid, a plurality of tension rods 10 may be formed on each plate, the rods being spaced longitudinally and also circumferentially.

In the free state (FIG. 1) the inflatable chamber 2 is radially distant from the external support 1. At that time, it is preferable that the plates 9 contact each other in the circumferential direction. When the rod 10 is pulled outward from the inflatable chamber 2 and the support 1, the plate 9 pulls the outer wall 3 of the inflatable chamber 2, moves toward the inner surface of the support 1, and presses and holds the outer wall 3. (FIG. 2) The outer wall 3 is circumferentially elongated and the plates 9 are arranged around a longer circumference and therefore move away from each other. The plate 9 must be sufficiently rigid to press the outer wall 3 against the support 1 evenly over its entire area. The material may be metal (regular steel, stainless steel, aluminum, etc.) or plastic.

While the expandable chamber 2 is freely communicating with the outside,
The inner wall 4 has a slight circumferential extension, here the inner diameter
Let's call it DGO.

This is the standby state for use of the press according to the invention. Note that the outer wall 3 of the inflatable chamber 2 is continuously pressed against the inner surface of the rigid external support 1. As mentioned above, plate 9 and tension rod 10 are merely examples of mechanical coupling means and may be replaced by equivalent means. The dimensions of the press, in particular the diameter of the expandable chamber 2 and the diameter of the support 1, are determined by the diameter of the object to be compressed. Before the compressed object is compressed, DO
(See the upper half of Figures 3 and 4)
Assuming that the diameter is DP at the end of compression (see the lower half of Figures 3 and 4), the expandable chamber 2 can easily absorb the compressed object
The inner diameter of the DGV (see bottom half of Figure 2) must be such that the DGV can be inserted. in fact
DGV is within the range of 1.015 times to 1.035 times of DO;
For example, it should be 1.020DO.

After the compressible object C is placed inside the evacuated expandable chamber 2 (upper half of Figures 3 and 4), the expandable chamber is brought to a certain maximum pressure value ( In this example, the pressure is increased to 50 bar). The diameter of the compressed body C is reduced to the value DP, which is
It is also the diameter of the inner wall 4 of . (Lower half of Figures 3 and 4) In this state where the body C to be compressed is completely compressed,
The inner wall 4 must return to approximately the free diameter DGO as shown in FIG. However, this inner wall may be reduced to a diameter equal to or less than DGO at the end of compression of the compressed body C. i.e. a diameter equal to about 0.85DGO, for example
It may also have DP. This is because the extra length of the circumferential inner wall 4 is absorbed up to a certain amount (to a certain limit given by the above relationship) by the longitudinal extension exerted by the pressure on the inflatable chamber 2.
A further reduction in the diameter DP at the end of compression when compared with the diameter DGO in the free state of the inner wall 4 is
You run the risk of mold wrinkles, which is desirable to avoid.

Taking into account the fact that the elongation of the outer wall 3 under the influence of the coupling means 9, 10 must not exceed the elongation that the elastic material of the inflatable chamber 2 can withstand, the outer support 1
The inner diameter D of can be reduced.

The press according to the invention may also be used to compress other objects than cylinders. That is, any object can be compressed as long as the expandable chamber can have an inner wall 4 having a shape similar to the shape of the outer surface of the object to be compressed in the free state. More generally, the reference dimension is the circumference P in cross-section rather than the diameter. At that time, the inner wall of the inflatable chamber is
It is necessary to ensure that the circumferential length P in the free state in the cross section is such that the circumferential length is within the range of P to 0.85P at the end of contraction.

As a specific example of the use of the press according to the invention, as described in French patent application no.
For the purpose of dewatering for drying, agricultural materials can be compressed into thin layers separated by sheets.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a press according to the present invention, showing the press before the expandable chamber and the external support are connected; FIG. 2 is a cross-sectional view of the press before the expandable chamber and the external support are connected. A diagram similar to the later Figure 1, in which the upper half of the diagram shows the expandable chamber when it has air at approximately external pressure, and the lower half of the diagram shows the expandable chamber when it is evacuated; 3 and 4 are a cross-sectional view and a vertical cross-sectional view, respectively, of the same press equipped with a compressed body inside the expandable chamber, and the upper half of each figure shows the state before compression;
The lower half is a diagram showing the state after compression. DESCRIPTION OF SYMBOLS 1... Rigid tubular external support body, 2... Annular expandable chamber, 3... Outer wall, 4... Inner wall, 6... Pressure adjustment pipe, 8... Air vent pipe, 9... Plate (fixed connection means) , 10... Center orientation (tension) rod (fixed connection means), C... Compressed body, D... Inner diameter of support body, DGO... Diameter of expandable chamber (when communicating with the outside),
DGV...Diameter of the expandable chamber (during exhaust), DO...Outer diameter of the compressed body (before compression), DP...Outer diameter of the compressed body (after compression).

Claims (1)

Claims: 1. A rigid external tubular support 1 and an annular inflatable chamber 2 having an outer wall 3 to be pressed against the inner surface of the support 1 and an inner wall 4 to be pressed against the compressed body C. A press machine for compressing an object to be compressed, wherein the outer wall 3 is pressed against the external support 1 over most of its area, and the maximum expansion pressure is such that the object C to be compressed is compressed to its maximum compression state. When the inflatable chamber 2 is inflated to a pressure equal to
A press machine characterized in that the pressure is 1 to 0.85 times the circumference of the same cross section when the pressure is approximately equal to the pressure of the surrounding medium. 2. Claim 1 characterized in that it has fixed connection means 9, 10 for holding the outer wall of the expandable chamber pressed against the external support 1 under any pressure or vacuum in the thermally expandable chamber. The press machine according to item 1. 3. The press machine according to claim 2, wherein the outer wall 3 is pressed and held against the external support 1 in a state in which its circumference is permanently extended. 4. The connecting means includes plates 9 in the inflatable chamber 2 and extending along the length of the inflatable chamber, the plates being continuous with each other in the circumferential direction of the inflatable chamber, each plate 9 having a At least one tension rod 10 is provided which sealingly penetrates the outer wall 3;
The rods 10 pass freely through the support 1, each rod being provided with traction and locking means for holding the outer wall 3 against the external support 1 by means of a plate 9 on the outside of the support. A press machine according to claim 2. 5. The inflatable chamber 2 is formed with an inflating and deflating pipe 6, which pipe 6 has a plate 9 in the inflatable chamber 2 and acts as a tension rod 10. The press machine described in section. 6. The press machine according to claim 5, wherein an air vent pipe 8 is formed in the expandable chamber 2.