Squeezing section spiral shaft and spiral oil press

Abstract

The invention provides a squeezing section spiral shaft, the root diameter of the squeezing section spiral shaft is gradually increased in the direction close to a cake outlet end in the axial direction, the tooth face screw pitch and the tooth back screw pitch of spiral squeezing teeth of the squeezing section spiral shaft are two unequal screw pitches, and the tooth face screw pitch is larger than the tooth back screw pitch. The width of the spiral groove of the squeezing section spiral shaft is gradually reduced in the direction close to the cake outlet end in the axial direction. Compared with the traditional design of a multi-section pressing screw, a plurality of lining rings and a smooth sleeve combined screw shaft, under the same conditions of yield, rotating speed and input power, the spiral calculation turns in the barrel are reduced, and the retaining amount of pressed oil in the barrel is correspondingly reduced, so that the unit pressure of the pressed oil in the barrel is greatly improved, and the yield of the pressed oil is increased. The spiral oil press has the advantages that the oil outlet efficiency of the low-temperature cold press can be improved, oil loss is reduced, and energy conservation and consumption reduction of a traditional spiral oil press are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of screw oil presses, and in particular to a pressing section screw shaft and a screw oil press. Background Art

[0002] At present, the screw shaft of the low-temperature cold press used in the low-temperature cold pressing process still adopts the conventional method of ordinary screw oil press, which is composed of multiple sections of pressing screws, multiple bushings and other pressing parts connected to the transmission main shaft through the inner hole key connection, resulting in too many calculated spiral turns in the pressing chamber and too much corresponding pressed oil in the pressing chamber, making the unit pressure of the pressed oil in the pressing chamber too low. The insufficient unit pressure will inevitably increase the dry cake residual oil rate and oil loss, and seriously affect the oil output efficiency of the low-temperature cold press.

[0003] The excessive number of spiral turns in the pressing chamber of the screw shaft also leads to a long pressing process from feeding to discharging of the oil, and a greater increase in the pressing temperature in the pressing chamber, which is very unfavorable for the cooling control of the pressing chamber of the low-temperature cold press, and also increases the power consumption of the ordinary screw oil press. Summary of the invention

[0004] The present invention proposes a pressing section screw shaft and a screw oil press, which eliminate the unfavorable factors such as too many spiral calculated turns in the pressing chamber, too large amount of pressed oil material, too low unit pressure, too long pressing process time, and too high pressing temperature rise in the pressing chamber caused by the conventional method of the ordinary screw oil press in the low-temperature cold press in the prior art due to the contraction extrusion section (i.e., pressing section) of the screw shaft still adopting the conventional method of the ordinary screw oil press. It provides technical support for the low-temperature cold press with increasingly perfect cooling measures to increase the unit pressure of the pressed oil material and reduce the loss of pressed oil, and also lays a technical foundation for the feasibility of reducing power consumption of ordinary screw oil presses.

[0005] The technical solution of the present invention is achieved in this way:

[0006] A first aspect of the present invention provides a pressing section spiral shaft, wherein the root circle diameter of the pressing section spiral shaft gradually increases along the axial direction approaching the cake outlet end, the tooth surface pitch S1 and the tooth back pitch S2 of the spiral pressing teeth of the pressing section spiral shaft are two unequal pitches, and the tooth surface pitch S1 is greater than the tooth back pitch S2, and the spiral groove width of the pressing section spiral shaft gradually decreases along the axial direction approaching the cake outlet end.

[0007] The present invention improves the pressing section of the traditional screw shaft. The present invention adopts a double-pitch design of the tooth surface and the tooth back, and cooperates with a frustum-shaped tooth root circle, thereby reducing the number of spiral calculation turns in the pressing chamber, and correspondingly reducing the amount of pressed oil in the pressing chamber, so that the unit pressure of the pressed oil in the pressing chamber is greatly improved. This advantage of the present invention can not only improve the oil output efficiency of the low-temperature cold press and reduce oil loss, but also is conducive to energy saving and consumption reduction of the traditional screw oil press.

[0008] Specifically, the depth of the spiral groove gradually decreases in the axial direction close to the cake outlet end. The purpose of this design is to make the feeding end of the spiral groove wide and deep, and the cake outlet end narrow and shallow. During the movement of the oil from the beginning to the end of the spiral groove, the oil is continuously squeezed by the narrowing and shallowing of the spiral groove at every moment.

[0009] Preferably, the width of the spiral teeth increases gradually along the axial direction close to the cake outlet end. The purpose of such design is to shorten the axial length of the spiral teeth and the total number of spiral circles as much as possible, so as to ensure that under the conditions of unchanged oil input, unchanged input power, unchanged screw shaft speed and unchanged total compression ratio, on the one hand, the unit pressure of the squeezed oil in the pressing chamber is increased, and the oil output efficiency is improved; on the other hand, the pressing time of the oil in the pressing chamber can be shortened, thereby reducing the pressing temperature and improving the oil output quality.

[0010] Specifically, the difference between the width at the beginning and the width at the end of any circle of the spiral groove is Δl=S1-S2.

[0011] Specifically, the length of the spiral shaft of the pressing section L=S2×n+b2, wherein n represents the number of spiral pressing tooth turns, and b2 represents the axial width of the end of the spiral pressing tooth.

[0012] Specifically, the end width of the spiral groove l=S2×n-b1-S1×(n-1), wherein n represents the number of spiral pressing tooth turns, and b1 represents the axial width of the starting end of the spiral pressing tooth.

[0013] A second aspect of the present invention provides a screw oil press, in which at least one pressing section screw shaft is installed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 This is a schematic diagram of the structure of a screw shaft of a pressing section of the present invention;

[0016] In the figure: 1. Spiral pressing teeth; 2. Spiral grooves; 3. Tooth surfaces; 4. Tooth backs. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Reference Figure 1 In a first aspect, an embodiment of the present invention provides a pressing section spiral shaft, wherein the root circle diameter of the pressing section spiral shaft gradually increases along the axial direction approaching the cake outlet end, the tooth surface 3 pitch S1 and the tooth back 4 pitch S2 of the spiral pressing tooth 1 of the pressing section spiral shaft are two unequal pitches, and the tooth surface 3 pitch S1 is greater than the tooth back 4 pitch S2, and the width of the spiral groove 2 of the pressing section spiral shaft gradually decreases along the axial direction approaching the cake outlet end.

[0019] The present invention improves the pressing section of the traditional screw shaft. The present invention adopts a double pitch design of the tooth surface 3 and the tooth back 4, and cooperates with the frustum-shaped tooth root circle to reduce the number of spiral calculation turns in the pressing chamber, and correspondingly reduces the amount of pressed oil in the pressing chamber, so that the unit pressure of the pressed oil in the pressing chamber is greatly improved. This advantage of the present invention can not only improve the oil output efficiency of the low-temperature cold press and reduce oil loss, but also is conducive to energy saving and consumption reduction of the traditional screw oil press.

[0020] In this embodiment, the screw shaft is cut by a CNC lathe. For an ordinary screw oil press, the inner hole of the screw shaft is key-connected to the transmission shaft; for a low-temperature cold press, both ends of the screw shaft are respectively connected to the power input shaft and the rotating support shaft by threads; the material of the screw shaft is 20CrMnTi; heat treatment: surface carburization, the depth of the carburized layer is 1.5 to 2 mm, and the hardness after quenching + tempering is HRc56 to 62.

[0021] Specifically, the depth of the spiral groove 2 gradually decreases in the axial direction close to the cake outlet end. The purpose of this design is to make the feeding end of the spiral groove 2 wide and deep, and the cake outlet end narrow and shallow. During the movement of the oil from the beginning to the end of the spiral groove 2, the oil is continuously squeezed by the narrowing and shallowing of the spiral groove 2 at every moment.

[0022] Preferably, the width of the spiral teeth 1 gradually increases in the axial direction close to the cake outlet end. The purpose of such design is to ensure that the length and number of turns of the spiral teeth 1 are shortened as much as possible under the conditions of unchanged oil input, unchanged input power, unchanged screw shaft speed, and unchanged total compression ratio. On the one hand, the unit pressure of the squeezed oil in the press chamber is increased, and the oil output efficiency is improved; on the other hand, the pressing time of the oil in the press chamber can be shortened, thereby reducing the pressing temperature and improving the oil output quality.

[0023] Specifically, the difference between the width at the beginning and the width at the end of any circle of the spiral groove 2 is Δl= S1 - S2 .

[0024] Specifically, the length of the spiral shaft of the pressing section L=S2×n+b2, wherein n represents the number of turns of the spiral pressing tooth 1, and b2 represents the axial width of the end of the spiral pressing tooth 1.

[0025] Specifically, the terminal width l of the spiral groove 2 is l=S2×n-b1-S1×(n-1), wherein n represents the number of turns of the spiral pressing tooth 1, and b1 represents the axial width of the starting end of the spiral pressing tooth 1.

[0026] The design process of the screw shaft of the pressing section of this embodiment is as follows:

[0027] According to the design task book and the traditional screw oil press design calculation method, after determining the free volume V1 and related dimensions of the screw shaft of the feeding section, the total compression ratio suitable for the low-temperature cold pressing process is selected, and the screw shaft of the pressing section is designed as follows according to the total compression ratio:

[0028] 1) The root circle diameter of the front end of the screw shaft of the pressing section is equal to the root circle diameter of the end of the screw shaft of the feeding section;

[0029] 2) The front section of the screw shaft in the pressing section has the same geometric shape and size as the rear section of the screw shaft in the feeding section;

[0030] 3) Preliminarily determine the tooth surface pitch S1, tooth back pitch S2 and the number of turns n of the spiral teeth;

[0031] 4) Calculate the axial length of the spiral pressing tooth = S2×n+10 (10 represents the width of the sharp angle of the tooth back reserved at the end of the spiral pressing tooth);

[0032] 5) Preliminarily determine the root diameter of the tooth back at the end of the spiral press tooth;

[0033] 6) Calculate the free volume V2 of the last spiral groove of the pressing section;

[0034] 7) Calculate the actual total compression ratio = V1 ÷ V2;

[0035] 8) Compare the calculated total compression ratio with the selected total compression ratio, and adjust the design parameters according to the error until the error between the calculated total compression ratio and the selected total compression ratio meets the requirements.

[0036] A second aspect of an embodiment of the present invention provides a screw oil press, in which at least one pressing section screw shaft is installed. When a double screw shaft is used, the two screw shafts have opposite rotation directions and are installed in combination in the pressing chamber of the screw oil press.

[0037] The pressing section spiral shaft of this embodiment can not only be applied to a spiral cold press to reduce the dry cake residual oil rate of the spiral cold press and improve the oil extraction efficiency; it can also be applied to a traditional spiral oil press, which is beneficial to energy saving and consumption reduction of the traditional spiral oil press.

[0038] The traditional spiral shaft adopts a multi-section combination design, with a large pitch at the front end and a small root circle diameter, and a gradually decreasing pitch at the rear end and an increasing root circle diameter. The adjacent spiral assemblies with different root circle diameters are connected by a tapered bushing transition, so that the spiral teeth and the tapered bushing have a large number of sections and a large axial size, with up to 9 sections of the spiral teeth (i.e., spiral teeth) and 6 tapered bushings, which results in the oil being squeezed inside the press chamber for a long time and at a high temperature, which is extremely unfavorable for the low-temperature cold pressing of the oil. The pressing section spiral shaft of this embodiment adopts a double pitch on the tooth surface and tooth back. The design, combined with the frustum-conical tooth root circle, makes the spiral groove wide at the front and narrow at the back, deep at the front and shallow at the back. During the movement of the oil from the beginning to the end of the spiral groove, the spiral groove becomes narrower and shallower at every moment, which reduces the number of spiral circles in the pressing chamber, and correspondingly reduces the amount of squeezed oil in the pressing chamber, so that the unit pressure of the squeezed oil in the pressing chamber is greatly improved. This advantage of the present invention can not only improve the oil output efficiency of the low-temperature cold press and reduce oil loss, but also is conducive to energy saving and consumption reduction of traditional screw oil presses.

[0039] The operating parameters of the domestically developed SLZ30 twin-screw oil press are as follows: daily processing of 28t peanut kernels, hot pressing of roasted seeds, main motor power of 37kw, screw shaft speed of 11rpm, and the space volume of the screw shaft in the feeding section is 0.002655m 3 The total number of spiral turns in the press chamber is 16.2, and the bulk density of peanut kernels is 570Kg / m 3 , the peanut kernel content in the pressing chamber is g = 0.002655m 3 ×0.6×2×16.2×570kg / m 3 =29.42kg (0.6 in the formula is the oil filling coefficient of the screw shaft in the feeding section), the axial thrust generated by the screw shaft is 36836Kgf, and the pressure per kilogram of peanut kernels in the pressing chamber is 36836kgf÷29.42kg=1252kgf.

[0040] Among them, the calculation formula for the total number of spiral turns N in the pressing chamber of the SLZ30 double-screw oil press is as follows:

[0041] N=L1÷d1+L2÷d2+(L3+C3)÷d3+(L4+C4)÷d4+(L5+C5)÷d5+(L6+C6)÷d6+(L7+C7)÷d7+(L8+C8)÷d8+L9÷d9

[0042] Among them, L i represents the length of the i-th screw, di represents the pitch of the i-th screw, i = 1, 2, ..., 9; C j represents the length of the liner corresponding to the j-th pressing screw, j=3, 4, …, 8; in this embodiment, L1, L2, …, L9 are 42mm, 170mm, 160mm, 150mm, 140mm, 120mm, 110mm, 90mm, 78mm respectively; the length of No. 1 pressing screw is 42mm, which is its length in the pressing chamber. The total length of No. 1 pressing screw is 364mm, and the remaining length is the lower end of the feed port, which is located outside the pressing chamber and is not involved in the calculation; d1, d2, …, d9 are 208mm, 114mm, 128mm, 112mm, 96mm, 80mm, 72mm, 64mm, 64mm respectively; C3, C4, …, C8 are 60mm, 60mm, 70mm, 70mm, 80mm, 90mm respectively; substituting the above parameters into the above formula, N=16.2 turns are calculated.

[0043] Under the conditions of unchanged oil input, unchanged input power, unchanged screw shaft speed, and unchanged total compression ratio, if the press section screw shaft of this embodiment is configured in the SLZ30 twin-screw oil press, the total length of the screw shaft can be shortened from the original 1812 mm to 976 mm, and the total number of spiral pressing teeth in the pressing chamber can be reduced from the original 16.2 turns to 7.59 turns; the effects achieved include:

[0044] Firstly, the oil content in the pressing chamber is reduced from 29.42Kg to 13.78Kg, and the pressure per kilogram of peanut kernels is increased from 1252Kgf to 2712.465Kgf, with the unit pressure increased by 116.65%. If the power of the main motor is reduced to 22kw, the pressure per kilogram of peanut kernels is 1589.4Kgf, which increases the unit pressure of the squeezed oil in the pressing chamber and reduces the output power of the motor, thereby achieving the purpose of energy saving and consumption reduction.

[0045] Secondly, the pressing time of oil in the press chamber is shortened from the original 88.36S to 41.4S, shortened by 53.1%, thereby effectively reducing the pressing temperature in the press chamber.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A screw shaft for a pressing section, characterized in that: The root circle diameter of the screw shaft of the pressing section gradually increases along the axial direction approaching the cake outlet end, the pitch S1 of the tooth surface (3) and the pitch S2 of the tooth back (4) of the spiral pressing teeth (1) of the screw shaft of the pressing section are two unequal pitches, and the pitch S1 of the tooth surface (3) is greater than the pitch S2 of the tooth back (4), and the width of the spiral groove (2) of the screw shaft of the pressing section gradually decreases along the axial direction approaching the cake outlet end.

2. A pressing section screw shaft according to claim 1, characterized in that: The depth of the spiral groove (2) gradually decreases along the axial direction approaching the cake outlet end.

3. A pressing section screw shaft according to claim 1, characterized in that: The difference between the width at the beginning and the width at the end of any circle of the spiral groove (2) is Δl=S1-S2.

4. A pressing section screw shaft according to claim 1, characterized in that: The length of the spiral shaft of the pressing section L=S2×n+b2, wherein n represents the number of turns of the spiral pressing teeth (1), and b2 represents the axial width of the end of the spiral pressing teeth (1).

5. A pressing section screw shaft according to claim 1, characterized in that: The end width l of the spiral groove (2) is S2×n-b1-S1×(n-1), wherein n represents the number of turns of the spiral pressing tooth (1), and b1 represents the axial width of the starting end of the spiral pressing tooth (1).

6. A screw oil press, characterized in that: At least one pressing section screw shaft according to any one of claims 1 to 5 is installed in the screw oil press.

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