Screw oil press chamber pressure monitoring device

Abstract

A pressure monitoring device for monitoring the pressure of a screw oil press chamber, comprising: a fixing mechanism located at the rear end of the pressure monitoring device, used to detachably fix the pressure detection device between the cage plates radially outside the chamber; a force measuring mechanism, comprising: a force transmission sheet located at the front end of the pressure monitoring device, used to radially insert into the oil discharge gap of the chamber, a force measuring element located at the rear side of the force transmission sheet, used to sense the pressure of the chamber transmitted by the force transmission sheet; and a limiting mechanism, comprising at least two limiting arms extending from the front end of the fixing mechanism to the front side, so as to hold the force transmission sheet and the force measuring element therebetween, wherein the front end of the limiting arm is used to slidably clamp the force transmission sheet. The installation of the pressure monitoring device and the real-time monitoring of the chamber pressure can be completed without changing the structure of the oil press itself.

Description

Technical Field

[0001] The invention relates to a screw oil press chamber pressure monitoring device Background Art

[0002] Human production and life cannot do without oils and fats. As a necessity in people's daily life, edible oils and fats provide energy and nutrients for human health. There are two main processing technologies for vegetable oils and fats, namely mechanical pressing and solvent extraction.

[0003] Screw oil press and hydraulic oil press are two types of mechanical oil pressing equipment commonly used in the industry. Among them, the screw oil press has become the mainstream oil making equipment due to its continuous operation capability and high degree of automation. The core structure of the screw oil press is the pressing chamber, which consists of a pressing cage (a cylindrical space composed of a series of continuous pressing bars or pressing rings) and a pressing screw (a screw with gradually increasing diameter and gradually decreasing pitch). The oil pressing process is that from the feed inlet to the cake outlet, the oil enters a series of shrinking spaces under the rotation of the pressing screw, that is, the gap between the pressing screw and the pressing chamber is constantly shrinking, so that the oil produces uneven and increasing friction resistance inside the high-pressure pressing chamber, causing the oil to gather into oil droplets and flow out from the oil discharge gap (slots or ring gaps). Therefore, the size, distribution and pressure increase rate of the pressing chamber pressure are one of the core parameters affecting the efficiency of oil pressing, and are also an important basis for the design and operation of the oil press. The pressing chamber pressure includes the radial pressure, axial pressure and tangential pressure on the pressing material in the chamber. The pressure monitoring target of the screw oil press is mainly the radial pressure of the pressing chamber.

[0004] At present, some scholars have proposed relevant research on the test methods for obtaining chamber pressure data, which can be mainly divided into three categories: direct measurement method, indirect measurement method and simulation calculation method.

[0005] The direct measurement method is to use a pressure sensor to directly obtain the pressure data of the press chamber. However, due to the limitations of the press chamber structure, it is difficult to install the pressure sensor, and the press chamber structure needs to be adjusted or modified. Opening a hole in the press chamber or replacing the standard press bar with a special press bar to install the pressure sensor is currently a more direct and effective method to obtain the pressure data of the press chamber. However, the press chamber is a high-pressure, high-oil, and high-friction environment. The direct pressure sensor or its special press chamber or press bar structure will fail quickly due to wear and tear and cannot continue to work.

[0006] Indirect measurement of the chamber pressure is mostly done by measuring the strain or displacement of the press bar, and then converting it into pressure data based on force analysis. In this method, it is difficult to standardize the relationship between the deformation and the pressure value because the force conditions of the press bar are very complex, so the accuracy and reliability of the measurement results are difficult to guarantee. By installing a direct pressure sensor and a press bar strain sensor in the same area of ​​the chamber at the same time, the direct pressure measurement data can be associated with the press bar strain data under the pressing condition, thereby realizing the calibration of the indirect pressure measurement data. However, as the press bar wears during operation, its strain behavior will deviate from the calibration relationship, so long-term stable measurement cannot be achieved.

[0007] The simulation calculation method uses computer software to simulate and assume the structure of the press chamber and the properties of the material to be pressed, establish an oil pressure model in the press chamber, and obtain the influence of the press chamber parameters on the law of pressure change. This method lacks actual measurement and cannot guide industrial production.

[0008] The Chinese invention patent with application publication number CN110172371A discloses a "screw oil press chamber pressure detection device and a chamber equipped with the device". The invention replaces several pressing bars on the chamber of the oil press with a pressure detection device with radial through holes on the base, and installs a pressure sensor in the radial through hole, so that the sensor is in direct contact with the material to be measured, and directly measures the pressure in the chamber. This method requires replacing some standard pressing bars in the chamber of the oil press with special pressing bars for detection, which is not only cumbersome to install, but also the special pressing bars have reduced strength due to the through holes, and are prone to wear in the high temperature, high pressure and high friction environment of the chamber, and the replacement cost is high.

[0009] The Chinese invention patent with application publication number CN108007616A discloses a "pressure monitoring device for the pressing chamber of a screw oil press". The invention derives pressure through an elastic transmission mechanism and acts on a pressure sensor to obtain pressure data. In this method, because the force transmission effect is closely related to the material mechanical properties of the elastic transmission mechanism, the use of common materials can only obtain a smaller pressure measurement range, and high-performance materials are difficult to obtain, so the practical application is limited.

[0010] In summary, there is currently no reliable way to obtain the size, distribution and dynamic laws of the chamber pressure (especially radial pressure) of the screw oil press, resulting in the operation and design of the oil press still being based mainly on experience.

[0011] Therefore, in order to ensure the healthy development of the oil pressing industry, it is urgent to develop a device that can directly measure the radial pressure of the press chamber. Summary of the invention

[0012] In view of the problems that the existing test methods for measuring the radial pressure of the press chamber are cumbersome, the calibration of the press bars is difficult, the press chamber structure needs to be changed, and the accuracy of the data cannot be guaranteed, the present invention aims to provide a pressure monitoring device which is easy to assemble and disassemble, simple to test, highly versatile, and can realize offline calibration of the press bars, so as to obtain accurate radial pressure data of the press chamber without changing the structure of the oil press itself.

[0013] The pressure monitoring device of the present invention is used to monitor the pressure of the pressing chamber of a screw oil press, and comprises: a fixing mechanism, located at the rear end of the pressure monitoring device, and used to detachably fix the pressure detection device between the pressing cage plates radially outside the pressing chamber; a force measuring mechanism, comprising: a force transmission sheet, located at the front end of the pressure monitoring device, and used to be radially inserted into the oil discharge gap of the pressing chamber forward, a force measuring element, located at the rear side of the force transmission sheet, and used to sense the pressing chamber pressure transmitted by the force transmission sheet; and a limiting mechanism, comprising at least two limiting arms extending from the front end of the fixing mechanism to the front side, so as to hold the force transmission sheet and the force measuring element therebetween, wherein the front end of the limiting arm is used to slidably clamp the force transmission sheet.

[0014] According to a pressure monitoring device of one embodiment, the fixing mechanism comprises a bracket having an end plate, the limiting mechanism being connected to the end plate; and two side walls for being detachably fixed to opposite sides of two adjacent pressing cage plates.

[0015] According to one embodiment, the pressure monitoring device also includes a return spring, whose front end is attached to the rear side of the force transmission sheet and whose rear end extends toward the force measuring element to abut against the force measuring element, wherein the rear end of the force transmission sheet for abutting against the sensing part of the force measuring element is located in the cavity of the return spring.

[0016] According to one embodiment, the pressure monitoring device further includes a heat insulation ring arranged on the front side of the force measuring element. When the pressure monitoring device is in use, the heat insulation ring is located outside the pressing chamber of the oil press, and its through hole allows the rear side of the force transmission sheet to pass through and abut the sensing part of the force measuring element.

[0017] The pressure monitoring device of the present invention can complete the installation of the device and the real-time monitoring of the pressing chamber pressure without changing the structure of the oil press itself, and the installation and measurement of the device are not affected by the replacement of the pressing bars. In addition, the main structural parts of the pressure monitoring device of the present invention can be obtained by using readily available plates through simple cutting, bending and other means according to the required size, and can be assembled and installed through simple and flexible bolting and other connection methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1a Shown is a portion of an oil press with a pressure monitoring device installed on it.

[0019] Figure 1b and Figure 1cThe pressure monitoring device is shown in an installed state, with its front end inserted into the oil discharge gap of the oil press.

[0020] Figure 2 It is an exploded schematic diagram of the pressing chamber pressure monitoring device of the present invention.

[0021] Figure 3 This is a schematic diagram of the pressure monitoring device of the present invention after assembly. DETAILED DESCRIPTION

[0022] Figure 1a The figure shows a part of an oil press, the press chamber of which is surrounded by a plurality of press bars 12 extending in the axial direction thereof, and a plurality of press cage plates 11 perpendicular to the press bars are used to fix the position of the press bars. After the press cage plates are closed, the press bars can form a cavity-type structure, constituting the press chamber. The axial gap formed between adjacent press bars 12 is the oil drainage gap. The front end of the front side portion of the pressure detection device 100 of the present invention is inserted into the oil drainage gap in the radial direction of the press chamber, and the rear side portion is fixed between adjacent press cage plates 102 by bolts and nuts. The pressure monitoring device of the present invention is also similarly applicable to the case where the press chamber is surrounded by a press ring. Figure 1b and Figure 1c The pressure monitoring device in the installed state is more clearly shown, wherein the rear end portion thereof is fixed between adjacent pressing cage plates 11 , and the force transmission sheet 10 at the front end thereof is radially inserted into the gap between adjacent pressing bars 12 .

[0023] Figure 2 Schematic diagram of the exploded view of the radial pressure monitoring device 100 of the pressing chamber of the present invention; Figure 3 It is a schematic diagram of the pressure monitoring device after assembly, and the direction from the rear side to the front side of the pressure monitoring device is the up-down direction shown in the figure. The pressure monitoring device 100 includes a rear side portion as a fixed part, and a front side portion constituting a detection part. The fixed part includes a positioning bracket 3 (a U-shaped groove opening to the rear side), and the two side plates of the U-shaped bracket have openings for inserting bolts 2. The detection part includes a limiting component 4 and a gasket 6, a pressure sensor 7, a heat insulation sleeve (heat insulation ring) 8, a force transmission sheet 10 and a reset coil spring 9 extending from the rear side of the force transmission sheet 10 to the rear side. The limiting component 4 can be fixedly connected to the bottom plate of the U-shaped bracket, thereby connecting the fixed part on the rear side and the detection part on the front side.

[0024] like Figure 1bAs shown, the U-shaped bracket, and thus the entire pressure monitoring device 100, is fastened between the pressing cage plates radially outside the pressing chamber by adjusting the nut at the end of the bolt 2 to vertically press between two adjacent pressing cage plates 102. The pressure monitoring device 100 may also include a sensor positioning bolt 1, which may pass through the bottom plate of the U-shaped bracket and the connecting plate of the limiting component 4, and vertically press the gasket 6 toward the front side to position the pressure sensor 7 stacked on the gasket 6, so that the front end surface of the pressure sensor 7 can be closely attached to the rear end surface of the heat insulating sleeve 8, and the front end surface of the heat insulating sleeve 8 can be pressed against the cross arm of the limiting component 4.

[0025] The limiting component 4 includes a connecting plate and two opposite L-shaped limiting arms extending vertically from the connecting plate to the front side. The connecting plate can be bolted to the bottom plate of the U-shaped bracket. The L-shaped limiting arm includes a straight arm portion on the rear side and a transverse arm portion on the front side. The straight arm portion can be attached and bolted to the connecting plate using the bent portion at the rear end thereof, or can be welded to the connecting plate (the connecting plate can also be omitted and the limiting arm can be directly fixed to the bottom plate of the bracket by bolting or welding). The gasket 6, the pressure sensor 7 and the heat insulation sleeve 8 can be held between the straight arm portions of the two opposite L-shaped limiting arms. The end edges (end faces) of the two transverse arm portions extending inward from the front end of the straight arm portion are used to clamp the force transmission sheet 10 in a slidable manner forward and backward, and the heat insulation sleeve 8 can be abutted against the rear side edge (surface) of the transverse arm portion. The front end of the reset coil spring 9 is connected to the rear end of the force transmission sheet 10, and can extend in the rear direction to abut against the front side of the heat insulation sleeve 8 or pass through the central through hole of the heat insulation sleeve 8 to abut against the non-sensing part of the pressure sensor 7. The L-shaped limiting arm is in the form of an integral sheet or at least the cross arm portion is in the form of a sheet.

[0026] like Figure 3 After assembly, the force transmission sheet 10 and the sheet-shaped cross arms on both sides are basically in the same plane, and its thickness is designed to be suitable for inserting into the oil drainage gap according to the width of the oil drainage gap between the pressing bars 101. The front end of the force transmission sheet 10 can be flush with the front side of the cross arm or slightly protrude to receive the radial pressure from the pressing chamber and be protected by the cross arm to the maximum extent to avoid left and right deviation.

[0027] Based on the commonly used screw oil press, the force transmission sheet 10 can be a hard stainless steel sheet with a thickness of 0.5-1.5mm and a width of 5-20mm, and its length can be 30-50% greater than the radial thickness of the pressing bar / pressing ring. The thickness of the cross arm part for anti-deflection located on both sides of the force transmission sheet 10 is basically the same as the thickness of the force transmission sheet 10, and the depth of the force transmission sheet inserted into the gap between the pressing bar / pressing ring is basically the same as the depth of the force transmission sheet inserted into the gap between the pressing bar / pressing ring, and the gap is matched with the force transmission sheet 10.

[0028] The heat-insulating sleeve 8 can be a cylinder or ring made of zirconia ceramics, and its outer diameter can be equivalent to that of the pressure sensor 7, and is used to support the pressure sensor and reduce the influence of the temperature of the pressing chamber on the pressure sensor. After the device of the present invention is assembled, the diameter of the internal channel defined by the heat-insulating sleeve 8 can be proportional to the width of the force-transmitting sheet 10 to achieve clearance fit, thereby also playing a limiting role in preventing the force-transmitting sheet 10 from deflecting. The outer diameter of the heat-insulating sleeve can be consistent with the outer diameter of the pressure sensor, and its thickness can be consistent with the difference between the length of the force-transmitting sheet and the radial thickness of the pressing bar / pressing ring.

[0029] The pressure sensor 7 may be a weighing type micro pressure sensor with a small size and a low height, which is placed on the heat insulating sleeve 8 and can contact the rear end of the reset coil spring 9. The sensing part of the pressure sensor 7 (e.g., the force-bearing convex point in the center) is exposed to the through hole of the heat insulating sleeve 8, and the rear end of the force conducting sheet 10 can pass through the through hole of the heat insulating sleeve 8 and approach the force-bearing convex point.

[0030] The front end of the reset coil spring 9 is connected to the rear side of the force transmission sheet 10, for example, it is sleeved on the rear side of the force transmission sheet, and extends laterally to abut against the front side of the heat insulation sleeve 8 or passes through the central through hole of the heat insulation sleeve 8 to abut against the non-sensing part of the pressure sensor 7. For example, small-diameter spiral holes can be opened on both sides of the rear side of the force transmission sheet 10 for connecting the front end of the reset coil spring 9, and the rear end of the force transmission sheet 10 for directly contacting the sensing part of the pressure sensor 7 (for example, the protrusion at the rear end of the force transmission sheet 10) is smaller in width and is located inside the reset coil spring 9.

[0031] When the force transmission sheet 10 inserted into the oil discharge gap under the protection of the limit arm is pushed by the radial pressure from the press chamber and displaced in the rear direction, the force can be applied vertically to the force-bearing convex point of the pressure sensor 7. When the radial pressure gradually decreases, the reset coil spring 9 can help the force transmission sheet 10 avoid the situation where the oil discharge gap is blocked by the crude oil cake and the force transmission sheet 10 cannot be restored to its original position. During this period, the reset coil spring 9 is always outside the press chamber because its diameter is much larger than the width of the oil discharge gap, and it also prevents the force transmission sheet 10 connected to it from falling into the oil discharge gap or the press chamber.

[0032] The U-shaped positioning bracket 3 is provided with a hole for installing the bolt 2. The bolt 2 is parallel to the pressing chamber or the pressing ring and perpendicular to the pressing cage plates on the adjacent two sides. The bolt 2 is tightened between the pressing cage plates by adjusting the nut thereon, so that the pressure sensor device can be fixed on the outside of the pressing chamber.

[0033] During installation, first push the assembled pressure monitoring device 100 into the gap between the pressing cage plates, and then push the force transmission sheet 10 and the limiting arms (their cross arms) protected on both sides into the gap between the pressing bars / pressing rings. The extension of the force transmission sheet and the limiting arms inside the pressing chamber should not exceed the inner surface of the pressing chamber. The front side of the heat-insulating sleeve 8 abutting against the rear side of the cross arm can limit the insertion depth, and the insertion depth of the limiting arm does not exceed the front and rear width of its cross arm. Then, use the bolts 2 and nuts (for example, by tightening the nuts at both ends of the bolts 2 between two adjacent pressing cage plates) to fix the relative position of the device to the pressing chamber and the pressing cage plates. Finally, adjust the degree of compression between the pressure sensor 7 and the outer surface of the pressing bar by the sensor positioning bolt 1.

[0034] According to the embodiments described above, the main structural components of the pressure monitoring device of the present invention, such as the U-shaped bracket, the connecting plate of the limiting component, the L-shaped limiting arm, the force transmission plate and other components can be obtained by using readily available plates according to the required size through very simple cutting, bending and other means, and can be assembled and installed through simple and flexible bolting and other connection methods.

[0035] Many features of the above embodiments may be modified.

[0036] The connecting plate of the limiting component 4 can be omitted, and the L-shaped limiting arm can be attached and bolted to the bottom plate of the U-shaped bracket by using the bent plate portion at the rear end thereof, or can be directly welded to the bottom plate.

[0037] A limiting cylinder 5 can be added between the limiting arms to facilitate stacking of gaskets, pressure sensors, heat insulation sleeves, washers and other components, such as Figure 2 and Figure 3 In this case, the front end of the stopper, or together with the front side of the thermal insulation sleeve, can limit the depth of the force transfer plate and the stopper arm inserted into the oil drainage gap. The diameter of the internal channel defined by the gasket and the thermal insulation sleeve is close to the width of the force transfer plate, which can also reduce the deflection of the force transfer plate.

[0038] The thickness of the cross arm portion of the limiting arm is usually equal to or slightly greater than the thickness of the force transmission sheet. Therefore, gap limiting plates can also be attached (for example, pasted) on the two side surfaces defined by the opposing cross arm portions, which can be located on the side surfaces of the cross arm portions of the two limiting arms (that is, the two side surfaces of the force transmission sheet), and can fit tightly to the two side surfaces of the cross arm portions to form a gap fit with the side surfaces of the force transmission sheet to prevent the force transmission sheet from deflecting in the thickness direction. Thereby, during the pressure monitoring process, the force transmission sheet is more stably maintained in the circumferentially closed or semi-closed narrow gap formed by the two cross arm portions and the thin sheets on both sides, so that the force transmission sheet can slide back and forth, but no lateral deflection occurs to affect the precise transmission of the radial pressure of the pressing chamber. The thickness of the gap limiting plate can be 0.5-1mm, and the depth of insertion into the gap between the pressing bar / pressing ring is 20-50% less than the depth of insertion of the force transmission sheet into the gap between the pressing bar / pressing ring.

[0039] When the thickness of the cross arm portion for clamping the force conduction sheet is relatively large, the narrow slit may also be formed by forming grooves extending forward and backward on the inner side of the cross arm portion, so that the force conduction sheet can be clamped more stably in the opposing grooves.

[0040] The main advantages of the pressure monitoring device of the present invention include:

[0041] (1) Without changing the structure of the oil press itself, the installation of the device and the real-time monitoring of the chamber pressure can be completed. The device of the present invention uses the oil discharge gap of the press bar as the outlet channel of the chamber pressure, and uses the press cage plate as the fixed installation base, which widely matches the general structure and standardized components of mainstream industrial oil presses. The chamber of an industrial oil press is composed of a combination of standard parts of the press bar. The service life of the press bar is limited. Generally, after 200 hours of continuous work, different degrees of wear will occur. At that time, the press bar that cannot work normally needs to be replaced. The installation and measurement of this device does not affect the normal operation of replacing the press bar.

[0042] (2) The device of the present invention can be separated from the oil press as a whole, and the pressure measurement data can be accurately calibrated on the material testing machine, and then installed on the oil press as a whole to collect the measured data. There is no need to rely on the complex stress-strain relationship of the press bar to estimate the pressure or rely on other direct pressure measurement devices to install and calibrate the pressure as in the indirect measurement method.

[0043] (3) The device is equipped with a heat-insulating ring to isolate the pressure sensor from the press chamber environment, which can effectively avoid the problems of inaccurate measurement results and low service life of the sensor caused by the high temperature in the press chamber. In addition, the pressure transmission mechanism is equipped with a reset spring. After the oil press finishes working, the reset spring can overcome the blockage of the material in the oil discharge gap and push the force transmission sheet out, thereby separating it from the pressure sensor element to protect the sensor. Finally, the pressure transmission sheet of the device is cheap, easy to obtain and easy to install, and can be easily replaced even if it is worn. This ensures long-term and stable monitoring of the press chamber pressure.

[0044] (4) The main structural parts of the pressure monitoring device of the present invention, such as the U-shaped bracket, the L-shaped limit arm of the limit component, the force transmission plate and other parts can be obtained by using readily available plates according to the required size through simple cutting, bending and other means, and can be assembled and installed through simple and flexible bolting, welding and other connection methods.

Claims

1. A pressure monitoring device for monitoring the pressure of a screw oil press chamber, comprising: A fixing mechanism, located at the rear end of the pressure monitoring device, is used to detachably fix the pressure detection device between the pressing cage plates on the radial outer side of the pressing chamber; Force measuring mechanism, comprising: A force transmission sheet, located at the front end of the pressure monitoring device, is used to be radially inserted into the oil discharge gap of the pressing chamber. A force measuring element, located at the rear side of the force transmission sheet, is used to sense the pressing chamber pressure transmitted by the force transmission sheet; and The limiting mechanism comprises at least two limiting arms extending from the front end of the fixing mechanism toward the front side to hold the force transmission sheet and the force measuring element therebetween, wherein the front end of the limiting arm is used to slidably clamp the force transmission sheet, Among them, the pressure monitoring device also includes an insulation ring arranged on the front side of the force measuring element. When the pressure monitoring device is in use, it is located outside the pressing chamber of the oil press, and its through hole allows the rear side of the force transmission sheet to pass through and abut against the sensing part of the force measuring element, and the at least two limit arms are a pair of opposing L-shaped limit arms, and the force measuring element and the insulation ring are maintained between the straight arm parts extending forward and backward, and the opposing cross arm parts are plate-shaped and are in the same plane as the force transmission sheet, so as to slidably clamp the two side edges of the force transmission sheet and can be inserted into the oil drainage gap together.

2. The pressure monitoring device as described in claim 1, wherein the fixing mechanism includes a bracket having an end plate, and the limiting mechanism is connected to the end plate; it also has two side walls for being detachably fixed to the opposite sides of two adjacent cage plates.

3. The pressure monitoring device as described in claim 1 further includes a return spring, whose front end is attached to the rear side of the force transmission sheet and whose rear end extends toward the force measuring element to abut against the force measuring element, wherein the rear end of the force transmission sheet used to abut against the sensing part of the force measuring element is located in the cavity of the return spring.

4. The pressure monitoring device as described in claim 1 further includes a positioning bolt that can extend forward through the fixing mechanism into the space between the limiting arms to press the force measuring element forward.

5. The pressure monitoring device as described in claim 2, wherein the bracket is fixed between two adjacent pressing cage plates by bolts passing through two side walls and nuts at both ends of the bolts.

6. The pressure monitoring device as described in claim 1 further includes a limiting cylinder held between the straight arm portions, the force measuring element is arranged in the limiting cylinder, and an insulation ring is stacked on the front end surface of the force measuring element.

7. The pressure monitoring device as claimed in claim 1, wherein the opposing cross arm portions define a narrow slot for the force transmission sheet to slide through, so as to provide sliding support on both side edges and side surfaces of the force transmission sheet.

8. The pressure monitoring device as described in claim 1 further includes a gap limiting plate attached to the side surfaces of the opposite cross arm portions to provide sliding support for the side surfaces of the force transmission plate.

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