MXPA00012226A - Device and method for a high pressure press - Google Patents

Abstract

A method to provide a high pressure press with a replaceable wear liner (1). The wear liner (1) is first inserted into the cylindrical pressure chamber (2) of the press and the pre-stressed by the application of an excess pressure above the yield point. The excess pressure is sufficient to increase the diameter of the wear liner and produce a residual radial compressive stress that holds the wear liner in place. When the wear liner is removed from the press it is dismantled. The advantage of the invention is that the replaceable wear liner, and a high pressure press comprising it, may be relatively inexpensive to produce and the replaceable wear liner may be quickly and simply replaced.

Description

DEVICE AND METHOD FOR A HIGH PRESSURE PRESS TECHNICAL AREA The present invention relates to a device and method used in conjunction with a high pressure press in the areas of isostatic pressing and high pressure treatment of substances. The present invention relates to a type of wear liner or liner for use in the high pressure press and a method for adjusting and replacing the wear lining or liner.

ANTECEDENTS OF THE TECHNIQUE High-pressure treatment now for some time has been used as a method to inactivate microorganisms and certain enzymes in food and other supplies. A decisive factor in obtaining a good result from a high pressure treatment is that the pressure is high enough. During the treatment of provisions, the pressure is usually brought to a pressure of between 1,000 - 15,000 bar. Within these presses high working pressures are generated inside the innermost cylinder, the pressure chamber, also described as a lining or internal pressure lining. In such highs Ref No.. 125642 pressures, the lining or internal lining is subjected to a very large fatigue stress. Failure of the liner or liner increases after some time in the operation and thus the liner or internal liner is usually designed and made as a wear lining or lining that is replaceable. To avoid failure of the liner or liner, the wear lining or liner is regularly replaced well in advance of the estimated service life. Such coatings or linings are expensive and consequently economically disadvantageous. In addition, each replacement of the lining or wear lining is a time consuming and expensive process. PCT / SE95 / 000153 discloses a particular type of liner or liner that is installed in a high-pressure pre-tensioning press of the wire wound or wire wound type. The linings or linings have to be replaced due to wear or fracture. The replacement operation includes an extraction step in which the wear lining or liner is removed and an insertion step in which a new liner or liner is placed on the site. To remove a liner or liner worn with, for example, a wire wound or wire wound press of the type described in PCT / SE95 / 000153, the piston portion of the internal pressure intensifier of the press is arranged with specially adapted tools of so that the pressure can be conducted to support the lining or liner support and the wear lining or lining. The pressure from the internal pressure intensifier is applied to the liner or liner support and to the lining or wear liner and these are led out of the cylindrical pressure chamber together under pressure. A new lining or wear lining is placed in the internal position of a lining support or liner and driven to an internal location in the cylindrical pressure chamber of the press by means of the internal pressure intensifier which is combined with special tools. In the wire winding or wire winding press described in PCT / SE95 / 000153 both the interior of the pressure chamber and the exterior of the coating or liner support are slightly conical in their cylindrical shape, schematically shown as a prior art. in Figure 1. The interior of the liner support or liner is cylindrical in its shape. The lining or wear liner is placed in the liner or liner holder as a shrink fit. When the support of the lining or liner with the wear lining or liner placed inside is led into the cylindrical pressure chamber of the press, they become compressed and therefore are prestressed in the radial direction to resist use under high pressure. pressures.

As stated above, failure or failure of the liner or liner increases after some time in the operation. A characteristic of the wear lining or liner described in PCT / SE95 / 000153 is that it is a very thin walled cylinder. This is designed in such a way that in the case of a fracture of the lining or lining, the additional force that must overload the frame of the press, whose force is proportional to that of the cross section of the lining or wear lining, is small. This means that the strength due to the fracture can surely be limited within the press avoiding costly or dangerous damage to the press or its surroundings.

A further feature of the wear lining or liner described in PCT / SE95 / 000153 is that it has a means on the outside of the wear lining or lining, for example a spiral groove cut along the total length of the surface exterior of the lining or wear lining. Thus if a wear lining or lining could crack or crack in service, after a pressurized medium from the high pressure chamber leaks out of the lining or wear lining. The pressurized medium having a leak is led to the outside of the press via a slot or other means on the outer covering surface of the wear lining or liner. This indicates that a cracking or cracking in the wear lining or lining has occurred and that appropriate action must be taken and the liner or liner replaced.

A disadvantage with the wear lining or liner described in PCT / SE95 / 000153 is that it must be mounted inside a lining support or wear lining, a cylinder with a conical exterior, which is expensive to manufacture. Its use is limited to presses with an internal pressure intensifier or a piston similarly capable of driving the lining or wear lining inside and outside the press. It is a long and difficult process to remove the lining or wear lining, as the lining or wear lining and the liner or liner support have to be driven out of the press by means of the combined internal pressure intensifier together with the special tools . The lining or wear lining with the liner or liner support is also long and difficult to install, as it has to be carefully driven into the press using the internal pressure intensifier together with the special tools for the position of the liner support or conical liner, with the lining or wear lining therein, within the cylindrical pressure chamber in a pre-tension condition.

In addition to the wire-wound or cable-wound pre-tensioning press of the type described in PCT / SE95 / 000153 there are alternative designs for high-pressure presses. High pressure presses may or may not have cylindrical pressure chambers that are pre-tensioned. For example, a sufficiently thick steel cylinder can be used as the cylindrical pressure chamber of a high pressure press without pre-tension. However, this type of press requires frequent safety inspections to signal damage when operating at the highest pressures. Damage to such thickness, hard cylindrical pressure chambers bring costly repairs or replacements.

DESCRIPTION OF THE INVENTION It is an object of the invention to provide a high pressure press with a wear lining or liner that is arranged in a residual radial compression tension stage. It is a further object of the invention to provide a wear liner or liner for a high pressure press that is easily replaceable and inexpensive in its manufacture. It is still another object of the invention to manufacture a high pressure press comprising a wear lining or liner that can be easily removed.

These and other objects are achieved according to the invention by means of a replaceable wear lining or liner with a slightly small outer diameter when compared to the inside diameter of a cylindrical pressure chamber. This is inserted into the cylindrical pressure chamber of a press without driving it under the application of pressure. Once in the interior position of the cylindrical pressure chamber, it is fixed in place by expanding it radially under excessive pressure. The wear lining is formed as a thick walled circular cylinder which can be easily removed using a method described in the following claims.

The lining or wear liner is inserted into the cylindrical pressure chamber of the. press. Once placed inside the cylindrical pressure chamber of a press the wear lining or lining is fixed on the site by means of the application of a radial pressure inside the lining or wear lining. This is accomplished by stopping the press and applying excessive pre-calculated radial pressure to the wear liner or liner within the press. This plastically deforms the lining or wear lining leaving it with a residual compression stress that acts as a radial pre-tension that opposes the high pressures generated in use.

To remove the lining or wear lining according to the present invention the press is opened so that the wear lining or lining can be accessed. A milling machine or other tool is inserted into the wear lining or liner and used to make a series of longitudinal cuts within the lining or wear lining. These cuts are made at a predetermined depth, running at the full length of the lining or wear lining, deep in the lining material or wear lining but without penetrating through the lining material or wear lining and without damaging the liner support. coating or liner or the innermost cylinder. The specially adapted milling machine is born with a cut that is approximately square in the cross section. Although the cuts are preferably square in cross section it is within the scope of the invention to make cuts of a different cross section.

Sufficient material is removed from the lining or wear lining by means of approximately square cuts so that the remainder of the thin layer of the lining material or wear lining at the bottom of the cut is sufficiently wide that it acts as a articulation class. The thin layer or joint is distorted under the compression force of the radial pre-tensioning remains in the wear lining or lining allowing the walls of the wear lining or lining to collapse together.

When the cuts have been completed and the lining or wear lining has collapsed into the cuts this can then be easily removed from the liner or liner support or the cylindrical pressure chamber without the use of pressures.

After the old wear lining has been disassembled and removed, a new lining or wear lining can be placed on site quickly and easily.

An economical high pressure press may be comprised of a wear lining or lining according to the invention. The press can have a relatively simple design as shown schematically in Figure 3. The cylindrical pressure chamber 3 can be manufactured as a cylinder from a single piece of solid steel. The cylindrical pressure chamber can alternatively be treated especially by using, for example, a self-seaming process to supply a harder, stronger and radially pre-stressed region in the inner part of the cylinder. In such a one-piece cylinder design the wear liner or liner can be placed directly into the cylindrical pressure chamber without any intermediate cylinder or lining support or wear lining.

A high pressure press comprising a replaceable wear liner or liner according to the invention can be used for the treatment of substances, as in PCT / SE95 / 000153. Such a press can also be used for the isostatic pressure of the preformed powder, for compacting objects produced from the powder or sintered shapes. Such pressure can also be advantageously used for the consolidation of the emptying. Many of the castings that contain internal fissures or other cracks after the emptying process. The treatment of the isostatic pressure in such a press can be used to end the internal cracks thus consolidating the casting material.

The advantages of this invention are many. The complete operation of changing the lining or wear lining takes very little time and so can be planned with the minimum interruption of production requirements. The invention can be grafted, removed, and replaced in high pressure presses without the application of pressure to drive it in or out. The invention does not require an internal pressure intensifier or other piston with or without special tools to drive it inside or drive it out of the press. This is simpler, faster and removes the risk of accidental damage due to inaccurate or erroneous application of pressure by mistake. The invention is inexpensive to manufacture in the form of a regular circular cylindrical shape, compared to the cost of pressure cylinders made with conical edges and cladding supports or wear lining with tapered outer diameters.

The invention can be incorporated in other types of high pressure presses, in addition to the type of press described in PCT / SE95 / 000153. The present invention can be used in high pressure presses designed with or without cylindrical pressure chambers or presses with solid cylindrical pressure chambers. Because the present invention is thus widely applicable it is to be expected to be manufactured from relatively large numbers with the implicit cost reduction that is involved.

The present invention enables high pressure presses to be operated at high pressures without their respective design pressures. The use of a wear liner with the characteristics disclosed in PCT / SE95 / 000153 means that close safety inspections of a pressure cylinder are not frequently required since the wear lining or liner is both easily replaceable and also indicates when the damage or wear has taken place as also describes the following.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention should be described in more detail in connection with the included drawings.

Figure 1 shows the prior art schematically with a wear lining or liner and a wear liner or wear liner of a high pressure press.

Figure 2 shows schematically a wear lining or lining according to the invention that is inserted into the cylindrical pressure chamber of a high pressure press.

Figure 3 shows a wear lining or lining according to the invention is expanded and pre-tensioned radially inside the cylindrical pressure chamber of a high pressure press.

Figure 4 shows a wear lining or lining according to the invention in the cylindrical pressure chamber position of a high pressure press.

Figure 5 shows cuts made inside a wear lining or lining according to the present invention above by removing it from a high pressure press.

Figure 6 shows a disarmed wear liner or liner according to the present invention removed from a high pressure press.

DESCRIPTION OF THE MODALITIES A replaceable wear liner or liner according to the present invention is formed as a thin walled circular cylinder, although other cylindrical shapes are within the scope of the invention. The outer diameter of a wear lining or liner according to the present invention is slightly small compared to the inside diameter of the cylindrical pressure chamber or the liner support or liner of a high pressure press.

The wear lining or liner 1 shown in Figure 2 is inserted into the cylindrical pressure chamber 2. Once placed inside the cylindrical pressure chamber 2 the wear lining or lining is fixed on the site by means of the application of excessive radial pressure. This is carried out by closing the pressure and • applying a pre-calculated excessive pressure to the lining or wear lining inside the press, as shown schematically by the letter "p" in Figure 3. This plastically deforms the lining or wear lining leaving it with a residual compression tension that acts as a radial pre-tension against the high pressures generated in use within the press.

The lining or wear liner 1 is placed inside the cylindrical pressure chamber 2 within the press. Two end caps 5, 6 are positioned in position at both ends of the wear lining or liner. The end caps 5.6 are each equipped with a temporary sealing means in the form of small end cap seals 7, 8 which fits within the ends of the lining or wear lining 1. The inner diameter of the liner or wear lining is undersized when it is first placed, so that the seals of the end cap 7, 8 have to be of a diameter slightly smaller than that of the seals for normal service. When the end caps 5, 6 have been positioned, the pressure can be applied within the wear lining or liner, by means of a low pressure fluid supported by means of an external pressure source released by means of such as a tube (not shown) arranged to pass through an end cap 5, 6.

Under sufficiently excessive pressure, before the point of production of the material, the wear lining is deformed and permanently expanded to a pre-calculated degree. The pressure is released. End caps 5, 6 are removed. The end portions of the wear liner or liner that are adjacent to the end caps and that are not under pressure may have a smaller inside diameter than the main part of the wear liner or liner that was exposed to the lining. Pressure. When necessary, the inner surface of the undeformed regions of the lining or wear lining adjacent to the end caps can be turned to increase the inner diameter so that it is the same as in the rest of the wear lining or lining . The turning can be completed before or after the expansion of the lining or wear lining.

A wear lining or lining according to the invention can be removed, either due to a cracking or fracture failure or as part of a planned maintenance operation, as the following.

One or both end caps 5, 6 with seals 7, 8 of the high pressure press are removed, depending on the type of press. A milling machine 9 or other type of cutting, milling or grinding tool is arranged to be decreased in the lining or wear lining 1 as shown in Figure 5.

The milling machine 9 is operated in order to make a series of longitudinal cuts 10 running in the total length of the liner or liner. Usually four cuts distributed approximately uniformly around the circumference provide a sufficient effect. Few or more cuts can be used depending on the diameter of the lining or wear lining. The cuts are made at a predetermined depth, as deep as possible in the lining material or wear lining, leading to a thickness of between 1-10% and preferably between 1-5% of the diameter of the liner or liner diameter of wear on the site.

After the cuts have been made and the specially adapted cutter removed the collapsed wear liner 11 can then be easily removed quickly from a standard lifting apparatus as shown in Figure 6. After the wear lining or lining old has been disassembled and removed a new lining or lining can be4 quickly and easily placed on site as described * above.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following claims is claimed as property:

Claims (9)

1. - A method for supplying a high-pressure press comprising a cylindrical pressure chamber and a replaceable wear lining or foil, characterized by the steps of inserting said lining or wear lining into said cylindrical pressure chamber to fix said lining or wear lining on the site with expansion by means of an internal pressure above the limiting load, so that said lining or wear lining is therefore arranged in a state of residual compression stress by increasing the diameter of said lining or wear lining.

2. - A method according to claim 1, characterized by closing the press and applying an internal fluid pressure to said wear lining or liner inside the press, in order to supply said residual compression tension.

3. - A method according to claim 2, characterized in that said internal fluid is applied by means of an external pressure source connected to the press.

4. - A method according to any of claims 1-3, characterized in that said wear lining or plating is plastically deformed, in order to supply said residual compression tension.

5. - A method according to any of claims 1-4, characterized in that the method still comprises the step of removing an existing lining or wear lining which replacement includes the steps of making one or more cuts in the internal surface of said lining or existing wear lining with the intention of causing the existing lining or wear lining • to collapse under the residual compression stress, remove the existing lining or collapsed wear lining.

6. - A method according to claim 5, characterized in that the one or more cuts that are made on the internal surface of said existing wear lining or lining are approximately square in cross section.

7. - A high pressure press comprising a cylindrical pressure chamber and a replaceable wear lining or trim arranged within the cylindrical pressure chamber in a state of residual compression stress, characterized in that the outer surface of said wear lining or lining it is in direct contact with the inner surface of said cylindrical pressure chamber.

8. - A high pressure press according to claim 7, characterized in that the wear lining is formed as a thin, circular walled cylinder.

9. - A high pressure press according to any of claims 7-8, characterized in that the wear lining or plating is deformed plastically, as a result of an expansion of the wear lining or lining after its insertion into the chamber pressure, so that a residual compression voltage is supplied.