Hydraulic press and method for pressing an object

Abstract

The present invention relates to a hydraulic press and a method for pressing different kinds of objects (such as briquettes). The hydraulic press includes a main cylinder (1) accommodating a fluid space (2) and a working piston (3), the rod (3a) of the working piston extending outside the main cylinder (1), and the working piston (3) being adapted to move in the fluid space (2) by means of hydraulic pressure. The hydraulic press also includes an accumulator (4) and a hydraulic circuit with valves. An impact piston (7) is arranged inside the working piston (3) that moves by means of hydraulic pressure, the impact piston (7) moving along the working piston (3) and being movable relative to the working piston (3) by means of hydraulic pressure. Additionally, a separate impact body (10) is arranged between the impact piston (7) and the object (14) pressed by the hydraulic press.

Description

Technical Field

[0001] The present invention relates to a hydraulic press defined in the preamble of claim 1 and a method of pressing an object defined in the preamble of claim 8.

[0002] The novel hydraulic press and method according to the present invention are very suitable for manufacturing briquettes from purified steel slag by high-pressure compression. Background Art

[0003] For example, the most advanced hydraulic presses operated hydraulically are disclosed in British Patent Specification GB2062517 A, US Patent Specification US2003167938A1, and Japanese Patent Specification JPH06-39599 A.

[0004] British Patent Specification GB2062517 A discloses a double-acting hydraulic press for pressing a product to be manufactured into dies (15, 16). The device has an outer punch (3) and an inner punch (5), both of which move towards the die by the same hydraulic pressure prevailing in the shared cylinder space (1). The device does not have a separate impact body that impacts the die at high speed. The device according to GB2062517 A also has an accumulator (12), but its purpose is completely opposite to the purpose of the solution according to the present invention, because it is used to slow down the downward movement of the inner blank holder towards the die. In addition, the pressure of the accumulator also lifts the inner punch (5) provided in the outer punch (3) to its upper position after the pressing step. This operation is also different from the solution according to the present invention.

[0005] US Patent Specification US2003167938 A1 discloses a very complex and huge anti-shock hydraulic press having independent internal impact bodies (15 / 25), and the ends of both impact bodies are impacted by hydraulic cylinders (14 / 25) at precisely determined impact distances (S1 / S2). The solution according to this US patent specification does not disclose an impact piston provided within the working piston and impacts the impact body with high power. This US patent specification also does not describe in more detail how the stroke is implemented. This patent specification incidentally mentions the term "accumulator" twice, but does not mention in any way the role it plays in performing the impact. This patent specification also does not mention that by opening the valve between the impact piston and the impact body, the accumulator allows the impact piston within the working piston to quickly impact the impact body that is pressing the material into the die.

[0006] Japanese Patent Specification JPH06-39599 A is also different from the solution according to the present invention. The JP patent specification discloses a cylinder (8) that reciprocates up and down hydraulically within a control cylinder (13) and has a ram (1) that presses into a die at its lower end. In the pressing step, high-pressure oil and cooling oil are initially supplied to a space (A1) provided within the cylinder (8) by a pump (PI) and to a space (A3) provided within the oil cylinder (8) by a pump (P2), respectively. At the end of the movement, high-pressure oil is supplied by the pump (PI) to both spaces (A1 and A3). In the pressing step, high-pressure oil is fed into a space (A2) provided within the cylinder (8) by the pump (PI) to lift the cylinder (8) to its upper position. The device does not have a separate impact body that impacts the die at high speed. However, the JP patent specification mentions that the hydraulic circuit associated with the device includes an accumulator (25), but the present application does not describe the use of the accumulator. Summary of the Invention

[0007] The present invention aims to eliminate the problems encountered in the prior art solutions and provide a new type of hydraulic press with a simple and inexpensive structure but with extremely high compression pressure and power to allow the production of very dense and hard briquettes by the hydraulic press and method according to the present invention. In particular, the object of the present invention is to allow the pressing out of very dense and hard briquettes from pure steel slag. The hydraulic press according to the present invention is described in the characterizing part of claim 1. Accordingly, the characterizing part of claim 8 describes a method for pressing different objects. Other embodiments of the present invention are described in the remaining part of the claims.

[0008] To achieve the above object, the solution according to the present invention relates to a hydraulic press including a main cylinder accommodating a fluid space and a working piston, the rod of the working piston extending outside the main cylinder, the working piston being adapted to move within the fluid space hydraulically, the hydraulic press including an accumulator and a hydraulic circuit with valves. Preferably, an impact piston is provided inside the working piston that moves hydraulically, the impact piston being movable relative to the working piston hydraulically along the working piston, and a separate impact body is provided between the impact piston and the object pressed by the hydraulic press.

[0009] The solution according to the invention also relates to a method of pressing different kinds of objects by means of a hydraulic press, which hydraulic press comprises an accumulator and a main cylinder and a working piston that encloses a fluid space, the rod of the working piston extending outside the main cylinder, and the working piston moving in a fluid space that is divided into a first fluid space and a second fluid space. Preferably, the pressing operation is divided into two successive steps, the first step being carried out hydraulically by moving the working piston towards the object to be pressed and the second step being carried out by an impact body connected to the hydraulic press and receiving a rapid impact from an impact piston arranged within the working piston, the impact movement being initiated by applying a significantly high pressure on a first end of the impact piston and by opening an oil flow hole connected to a hydraulic passage in the fluid space that prevents the impact piston from moving towards the object to be pressed.

[0010] One advantage of the solution according to the invention is that the device can be simple and that the ventilation structure gives the ram a high temporary impact speed and impact force to allow very hard and dense briquettes to be obtained from the material to be pressed (preferably pure steel slag). Also, the rapid and powerful pressing movement provided by the hydraulic press preferably allows various crushable objects to be crushed. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the following, the invention will be explained by means of a single embodiment, with reference to the accompanying schematic and simplified drawings, in which

[0012] Figure 1 is a cross-sectional view and a side view of the pressing part of the hydraulic press according to the invention before it is activated for pressing,

[0013] Figure 2 is Figure 1 a side view of the impact body used in the hydraulic press,

[0014] Figure 3 is a cross-sectional view and a side view of the pressing part of the hydraulic press according to Figure 1 in the first step of the pressing operation, and

[0015] Figure 4 is a cross-sectional view and a side view of the pressing part of the hydraulic press according to Figure 1 in the second step of the pressing operation.

[0016] This specification assumes that the hydraulic press operates in a substantially vertical position, with the stamping direction being substantially vertical, from top to bottom. Thus, terms such as "downward" etc. refer to the direction towards the die and the material to be pressed therein, while terms such as "upward" etc. refer to the opposite direction. Thus, the term "below" or the like refers to an object that is closer to the die and the material to be pressed therein than an object located above the said object.

[0017] Figure 1 and3 Figures 3 and 4 show the preferred pressing parts of the hydraulic press according to the present invention in different steps of the pressing operation. DETAILED DESCRIPTION

[0018] The central pressing part of the hydraulic press according to the present invention includes a main cylinder 1 that houses a fluid space 2 and an actual working piston 3 that reciprocates in the fluid space 2 by hydraulic pressure. Preferably, the main cylinder 1 is fixed relative to the hydraulic press frame, frame and hoses, valves, pumps, regulators, control systems or other components not shown in the figure.

[0019] The hydraulic press further includes an accumulator 4 that is connected to a first fluid space 2a above the working piston 3 through a fluid passage 4a. For example, the preferred position of the accumulator 4 is directly on top of the main cylinder 1. At the top of the main cylinder 1, the first fluid space 2a above the working piston 3 is also provided with a third oil flow hole 5 that connects to a high-pressure hydraulic passage having a hydraulic pressure of 300 bar (for example, as its working pressure). Control and cut-off valves not shown in the figure are provided in the high-pressure hydraulic passage. The accumulator 4 is connected to the first fluid space 2a above the working piston 3 through the fluid passage 4a, and the accumulator 4 receives the same working pressure as the first fluid space 2a through the third oil flow hole 5.

[0020] A second oil flow hole 6 is provided at the bottom of the main cylinder 1, in a second fluid space 2b below the working piston 3, and is connected to a hydraulic passage having control and cut-off valves not shown in the figure.

[0021] The tubular rod 3a of the working piston 3 is centrally hollow in its longitudinal direction and extends through the bottom la of the main cylinder 1 to a place farther than the main cylinder 1. At the upper end of the working piston 3, the hollow central part of the rod 3a extends into the first fluid space 2a above the working piston 3. Inside the rod 3a, within the hollow interior of the rod 3a, an elongated impact piston 7 with a cylindrical cross-section reciprocates by hydraulic pressure within the hollow interior. The upward movement of the impact piston 7 is restricted by a movement limiter 8 to prevent the impact piston 7 from moving upward and disengaging from the connecting rod 3a of the working piston 3. However, since the upper end of the impact piston 7 is connected to the first fluid space 2a above the working piston 3, the upper end of the impact piston 7 is subjected to the pressure prevailing in the first fluid space 2a.

[0022] When the rod 3a of the working piston 3 extends downward, a substantially cylindrical cylinder liner 9 is provided, the lower end of which is open and houses an impact body 10 that is adapted to reciprocate longitudinally within the cylinder liner 9. The upper end of the impact body 10 is provided with an impact surface 10a to receive the impact of the impact piston 7, and a plunger part 10b is provided below this, the cross-sectional diameter of which is equal to the inner diameter of the cylindrical cylinder liner 9. A rod part 10c is provided below the plunger part 10b, the diameter of which is preferably smaller than the plunger part, and the lower end of which has a ram 12 of the hydraulic press.

[0023] At the bottom of the working piston 3, below the main cylinder 1, between the lower end of the impact piston 7 and the impact surface 10a of the impact body 10, a third first oil flow hole 15 is provided, which, when viewed from the top of the pressing member, results in a first variable volume fluid space 7b of variable volume accommodated by the rod 3a of the working piston 3 and located below the impact piston 7. The first oil flow hole 15 is connected to a hydraulic passage having a control and cut-off valve not shown in the figure.

[0024] Below the cylinder liner 9, a guide bush 11 is connected as an extension of the cylinder liner 9. The rod portion 10c extending downward from the plunger portion 10b of the impact body 10 is adapted to reciprocate and perform an impact motion therein, such that the ram 12 of the impact body 10 projects out of the guide bush 11 and impacts, at high speed and high power, the material contained in the die 13 and constituting the object 14 to be pressed.

[0025] In the cylinder liner 9 below the plunger portion 10b of the impact body 10, a fourth oil flow hole 16 (when viewed from the top of the pressing portion) is provided, which results in a third fluid space 17 located below the plunger portion 10b of the impact body 10 within the cylinder liner 9. The fourth oil flow hole 16 is connected to a hydraulic passage having a control and cut-off valve not shown in the figure.

[0026] The hollow interior of the rod 3a of the working piston 3, the hollow interior of the cylinder liner 9, and the hollow interior of the guide bush 11 together form a substantially continuous concentric path within the working piston 3 and as an extension thereof in the cylinder liner and the guide bush 11, which serves as a conductor for the reciprocating motion of the impact piston 7 and the impact body 10.

[0027] For example, when manufacturing briquettes, the die 13 can be a substantially circular disk that can rotate about a vertical axis on a preferably flat and solid base 18 and has a plurality of circumferential through-holes similar to the cylinders of a spinner. Each through-hole is adapted to be filled with coal briquettes that make up the object 14 to be pressed and supported on the upper surface of the base 18. Depending on the die, one or all of the through-holes of the die can be filled at a time.

[0028] Preferably, the pressing operation of the hydraulic press includes at least two steps. In the first step, the briquette material is pre-pressed by the movement of the working piston 3, while in the second step, the impact piston 7 is activated to complete the pressing of the briquette by impact. Preferably, the impact is automatically initiated based on a trigger from a sensing element (such as a pressure gauge) provided in the hydraulic circuit of the hydraulic press. When the main pressure in the first fluid space 2a is at a predetermined level, the pressure gauge gives a trigger signal, and the control system of the hydraulic press opens the cut-off valves of the third and fourth first oil flow holes 15 and the fourth oil flow hole 16. Preferably, the sensing element is controllable to allow adjustment of the intensity of the impact.

[0029] For example, a pressed object composed of briquettes pressed out from pure steel slag is manufactured by the hydraulic press and method according to the present invention as follows:

[0030] Since the working piston 3 and its attached parts are in the Figure 1 upper position shown, there is hydraulic oil with a substantially normal pressure in the first fluid space 2a above the working piston 3 and in the accumulator 4. According to the structure, the accumulator has been slightly cooled. After that, since the working piston moves to its upper position, the size of the first fluid space 2a becomes smaller. Correspondingly, the second fluid space 2b below the working piston 3 becomes larger and is filled with hydraulic oil supplied through the second oil flow hole 6, so that the working piston moves to its upper position. The impact piston 7 is also in its upper position, and the first variable volume fluid space 7b between its lower surface and the impact surface 10a on the upper surface of the impact body 10 is filled with hydraulic oil supplied through the third first oil flow hole 15. Similarly, the impact body 10 is in its upper position, and the third fluid space 17 below its plunger part 10b is filled with hydraulic oil supplied through the fourth oil flow hole 16.

[0031] When the working piston 3 is in the above upper position, the third and fourth first oil flow holes 15 and the fourth oil flow hole 16 are closed, and the object to be pressed (such as a coal briquette) is placed in the mold below the punch 12 of the hydraulic press of the press. Thereafter, hydraulic oil is fed into the third oil flow hole 5 through a high-pressure pump, for example, to increase the pressure in the first fluid space 2a above the working piston 3 and in the fluid space of the accumulator 4. Preferably, for example, the pressure in the first fluid space 2a and the fluid space of the accumulator is increased to a minimum working pressure of about 300 bar. The increase in pressure causes the working piston 3 and the hydraulic press components 9, 10, and 11 connected thereto to move downward toward the mold 13, and the impact body 10 and the guide bushing 11 press the object 14 (such as a coal briquette) into the mold 13. Figure 3 The situation shown represents this step, which can also be called the first step of the pressing operation. When the counter pressure in the material to be pressed is high enough, the pressing movement will stop by itself. Although the pressure in the first fluid space 2a increases and the increased pressure acts on the upper surface of the impact piston 7, the movement of the impact piston 7 within the impact piston 7 relative to the impact piston 7 is blocked because the first variable volume fluid space 7b below the impact piston 7 is filled with hydraulic fluid, and since the valve of the hydraulic passage connected to the first oil flow hole 15 is closed, the hydraulic fluid can neither be pressed together nor flow out of the first variable volume fluid space 7b.

[0032] This will continue Figure 4The situation shown, which is the second step of the pressing operation, in which the third and fourth first oil flow holes 15 and the fourth oil flow hole 16, i.e., the cut-off valves located in the hydraulic channels leading to these oil flow holes, are opened. In fact, when the main pressure in the first fluid space 2a increases to a predetermined value and the pressure gauge, acting as a sensing element, sends a command to the control system to open the cut-off valves of the third and fourth first oil flow holes 15 and the fourth oil flow hole 16, this opening occurs automatically. Now, the hydraulic oil present in the first variable-volume fluid space 7b and the third fluid space 17 and fixing the impact piston 7 and the impact body 10 in place relative to the working piston 3 is discharged from the front of the impact piston 7 and the impact body 10 through the first oil flow hole 15 and the fourth oil flow hole 16, so that the pressure in the first fluid space 2a is rapidly released. With the help of the pressure of the accumulator 4, it enters the second variable-volume fluid space 7a of variable volume provided at the upper end of the rod 3a of the working piston 3. Due to its inertial force and the working pressure of the accumulator 4, the impact piston 7 impacts the impact body 10 at a very high speed and power. Therefore, the indenter 12 of the impact body 10 impacts the object 14 to be pressed and provided in the mold 13, such as a coal block, pressing it further together and packing it into a dense and hard coal block through the shaping action of the indenter 12 of the impact body 10. When pressing coal blocks, it is advisable to use a suitable binder, such as cement, bentonite, and / or lime, which can be mixed into the coal blocks.

[0033] After the pressing impact, hydraulic oil is fed into the second fluid space 2b, the first variable-volume fluid space 7b, and the third fluid space 17 through the second oil flow hole 6, the first oil flow hole 15, and the fourth oil flow hole 16 at sufficient pressure to lift the working piston 3 and its connected components and move them out of the mold. Thereafter, it is advisable to remove the compressed coal block from the mold 13 by rotating the mold disk until the briquette can fall below the mold disk through the mold disk. By rotating the mold disk until the next object 14 to be pressed is located below the indenter 12, the next pressing event can be initiated.

[0034] Those skilled in the art will understand that the different embodiments are not limited to the above examples and can vary within the scope of the appended claims. Importantly, the rapid and powerful impact on the impact object is achieved hydraulically.

[0035] Those skilled in the art will also recognize that the hydraulic press according to the present invention can not only press coal blocks but also other types of objects. For example, the hydraulic press can manufacture molded products, such as wooden, plastic, or metal products. Similarly, the hydraulic press according to the present invention can also be used in the same way as an impact machine to break individual objects or break continuous layers of materials.

Claims

1. A hydraulic press, comprising a main cylinder (1) accommodating a fluid space (2) and a working piston (3), the fluid space (2) having a first fluid space (2a) and a second fluid space (2b), a rod (3a) of the working piston extending outside the main cylinder (1), the working piston (3) being adapted to move in the fluid space (2) by hydraulic pressure, the hydraulic press including an accumulator (4) and a hydraulic circuit with valves, and an impact piston (7) provided inside the working piston (3) that moves by hydraulic pressure, the impact piston (7) moving along the working piston (3) and being movable relative to the working piston (3) by hydraulic pressure, wherein a separate impact body (10) is provided between the impact piston (7) and an object (14) pressed by the hydraulic press, characterized in that, Inside the rod (3a) of the working piston (3), a first variable - volume fluid space (7b) is provided between the impact piston (7) and the impact body (10), having a first oil flow hole (15) connected to a hydraulic passage to fill the first variable - volume fluid space (7b) in order to move the impact piston (7) to its impact position and to empty the first variable - volume fluid space (7b) in order to perform the impact movement of the impact piston (7).

2. The hydraulic press according to claim 1, wherein, The fluid space (2) of the main cylinder (1) includes a first fluid space (2a) on the first side of the working piston (3) and a second fluid space (2b) on the second side of the working piston (3), and wherein the accumulator (4) is hydraulically connected to the first fluid space (2a) of the main cylinder (1).

3. The hydraulic press according to claim 2, characterized in that, In order to move the working piston (3) towards the object to be pressed (14), the first fluid space (2a) has a third oil flow hole (5) connected to a high - pressure hydraulic pump through a hydraulic passage, and wherein in order to move the working piston (3) away from the object to be pressed, the second fluid space (2b) has a second oil flow hole (6) connected to a hydraulic pump through a hydraulic passage.

4. The hydraulic press according to any one of claims 1-3, characterized in that, The rod (3a) of the working piston (3) is a hollow tubular structure, one end of which extends outside the main cylinder (1) and the other end is extended by a cylinder bushing (9) and a guide bushing (11) concentric with the rod (3a), intended to guide the impact body (10) to impact the object to be pressed (14) due to the impact of the impact piston (7).

5. The hydraulic press according to any one of claims 1-3, characterized in that, The cylinder bushing (9) includes a third fluid space (17), the third fluid space (17) having a fourth oil flow hole (16) connected to a hydraulic passage to fill the third fluid space (17) in order to move the impact body (10) to its impact position and to empty the third fluid space (17) in order to perform the impact movement of the impact body (10).

6. The hydraulic press according to any one of claims 1-3, characterized in that, The first end of the rod (3a) of the working piston (3) houses a second variable - volume fluid space (7a), connected to the first fluid space (2a) and adapted to fill with hydraulic oil discharged from the fluid space (2a) and the accumulator (4) to complete the impact movement of the impact piston.

7. A method for pressing an object by a hydraulic press, the hydraulic press comprising an accumulator (4), a main cylinder (1) accommodating a fluid space (2), and a working piston (3), the fluid space (2) having a first fluid space (2a) and a second fluid space (2b), a rod (3a) of the working piston extending outside the main cylinder (1), the working piston (3) being adapted to move in the fluid space (2) divided into the first fluid space (2a) and the second fluid space (2b), characterized in that, The pressing operation is divided into two consecutive steps, the first step being performed hydraulically by the movement of the working piston (3) and the second step being performed by the impact body (10) connected to the hydraulic press and receiving a rapid impact from the impact piston (7) provided inside the working piston (3), entering the impact movement by applying a significantly high pressure from the first fluid space (2a) on the first end of the impact piston (7) and opening the first oil flow hole (15) connected to the hydraulic passage in the first variable - volume fluid space (7b) that prevents the impact piston (7) from moving towards the object to be pressed (14).

8. The method according to claim 7, characterized in that, In the step of performing the impact movement of the impact piston (7), first, the fourth oil flow hole (16) provided in the third fluid space (17) that prevents the impact body (10) from moving toward the object (14) to be pressed and connected to the hydraulic passage is opened, and at the same time, the first oil flow hole (15) provided in the first variable volume fluid space (7b) is opened or subsequently opened.

9. The method according to claim 7 or 8, characterized in that, At the start of the pressing step, the pressure acting on the first end of the impact piston (7) within the working piston (3) increases in the first fluid space (2a) and the accumulator (4) hydraulically connected thereto. At the same time, the working piston (3), the impact piston (7), the cylinder liner (9) of the hydraulic press connected to the working piston (3), the impact body (10), and the guide liner (11) move toward the object (14) to be pressed, and then the rapid impact movement of the impact piston (7) is performed by opening the first oil flow hole (15) and the fourth oil flow hole (16).

10. The method according to claim 7 or 8, characterized in that, The pressure acting on the first end of the impact piston (7) is sensed by a sensing element, and when the pressure exceeds a predetermined limit, the rapid impact movement of the impact piston (7) is initiated by opening the first oil flow hole (15) and the fourth oil flow hole (16).

11. The method according to claim 7 or 8, characterized in that, For the next pressing event, the working piston (3), the impact piston (7), and the impact body (10) return to their initial positions by filling the first fluid space (2a), the first variable volume fluid space (7b), and the third fluid space (17) through the second oil flow hole (6), the first oil flow hole (15), and the fourth oil flow hole (16).

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