Continuous vulcanization extrusion production line and pipe closing method for continuous vulcanization extrusion production line

Abstract

A pipe closing method for a continuous vulcanization extrusion production line relates to the technical field of rubber sleeve cable production, and comprises the following steps: when rubber extrusion is finished, steam pressure is kept unchanged, and cooling water is filled into a vulcanization pipeline, so that the cooling water in the vulcanization pipeline gradually spreads towards rubber extrusion equipment; the spreading speed is consistent with the linear speed of the rubber sleeve cable during normal production; the movement of the rubber sleeve cable during normal production is simulated through the change of the water level, so that the vulcanization time of all parts of the tail section of the rubber sleeve cable is basically kept consistent, and the problem of non-uniform vulcanization in the prior art is solved. The embodiment of the invention further provides a continuous vulcanization extrusion production line which can be used for executing the pipe closing method for the continuous vulcanization extrusion production line, so that the yield of the tail section cable is improved.

Description

Technical Field

[0001] The invention relates to the technical field of rubber sheathed cable production, in particular to a continuous vulcanization extrusion production line and a pipe blocking method for the continuous vulcanization extrusion production line. Background Art

[0002] In the production process of rubber sheathed cables, the continuous vulcanization extruder is one of the key equipment. In the traditional continuous vulcanization production process, the vulcanization tube in the normal production stage passes through the vulcanization pipeline and the cooling pipeline at a fixed speed, and the residence time of the rubber tube in the vulcanization pipeline is consistent, which ensures the uniformity of vulcanization. In the final stage of production, when the rubber extrusion is completed, the entire production line will stop running, and the rubber sheathed cable will stay in the vulcanization pipeline to vulcanize the tail section, that is, the existing pipe-blocking process. Such a pipe-blocking process has great disadvantages. Since the end of the rubber sheathed cable near the cooling pipeline enters the vulcanization pipeline first, if the vulcanization time is set according to the vulcanization degree of this part, the end of the rubber sheathed cable near the rubber extrusion equipment will have a problem of insufficient vulcanization due to the short time of entering the vulcanization pipeline. On the contrary, if the vulcanization time is set according to the vulcanization degree of the end near the rubber extrusion equipment, the end near the cooling pipeline will have the problem of over-vulcanization. Therefore, under the existing pipe-blocking process, the tail section of the rubber sheathed cable often produces 50~80 meters of waste due to the problem of uneven vulcanization, resulting in material waste. Summary of the invention

[0003] The object of the present invention is to provide a pipe blocking method for a continuous vulcanization extrusion production line, which is simple to operate, has low requirements on equipment, and can effectively solve the problem of high scrap rate in the tail section of continuous vulcanization extrusion production.

[0004] Another object of the present invention is to provide a continuous vulcanization extrusion production line, which can be used for the pipe sealing method of the above-mentioned continuous vulcanization extrusion production line to improve the yield of the tail section cable.

[0005] The embodiment of the present invention is achieved as follows: A pipe-blocking method for a continuous vulcanization extrusion production line, the continuous vulcanization extrusion production line comprising a rubber extrusion device, a vulcanization pipeline and a cooling pipeline connected in sequence; The pipe blocking method includes: At the end of rubber extrusion, keep the steam pressure constant and add cooling water into the vulcanization pipe, so that the cooling water in the vulcanization pipe gradually spreads to the rubber extrusion equipment, and the spreading speed is consistent with the line speed of the rubber sheathed cable during normal production; When the cooling water spreads to the rubber extrusion equipment, stop injecting cooling water and steam, and drain the cooling water after the rubber-sheathed cable has cooled.

[0006] This pipe-blocking method is suitable for production lines with a certain elevation difference between the extrusion equipment and the cooling pipe outlet, such as vertical, inclined, and semi-catenary rubber vulcanization production lines. The principle is that during the pipe-blocking process, the movement of the rubber-sheathed cable during normal production is simulated by the change of water level, so that the rubber-sheathed cable that enters the vulcanization pipe first is cooled by contact with cooling water, and the rubber-sheathed cable that enters the vulcanization pipe later is cooled by contact with cooling water, so that the vulcanization time between the various parts of the tail section of the rubber-sheathed cable is basically consistent, thereby improving the problem of uneven vulcanization in the prior art.

[0007] Furthermore, the spreading speed of cooling water is converted by monitoring the rising speed of water pressure at the end of the cooling pipe, and the injection speed of cooling water is adjusted by comparing the spreading speed with the linear speed of the rubber-sheathed cable during normal production. Since there is an elevation difference in the vulcanization pipe in the continuous vulcanization extrusion production line, the water level is in a state of continuous increase during the water injection process, and as the water level increases, the water pressure at the end of the cooling pipe will continue to increase. The rate of change of water pressure can be converted into the water level rising speed (i.e., spreading speed) through a preset program, and then compared with the linear speed of the rubber-sheathed cable during normal production. If the spreading speed is less than the production speed, the water inlet is increased, otherwise the water inlet is reduced. In addition, multiple water level detectors can be set in the vulcanization pipe to assist in calibrating the water level rising speed and optimize the preset program, so that the preset program can control the spreading speed more accurately.

[0008] Furthermore, the steam pressure is obtained by monitoring the air pressure at the starting end of the vulcanization pipeline, and the steam injection speed is adjusted by the change of air pressure. In order to maintain the same vulcanization speed as in normal production, the steam pressure needs to be maintained during the pipe stuffing process. The steam used here is saturated steam, and the air pressure of saturated steam determines the vulcanization temperature. The relationship between the two can be checked in the following table.

[0009] Table 1. Relationship between saturated steam pressure and temperature Pressure / Mpa 0.1 0.2 0.3 0.4 0.4 0.6 0.7 0.8 0.9 1.0 Temperature / ℃ 119.9 132.9 142.8 151.1 158.1 164.2 169.2 174.6 179.1 183.2 Pressure / Mpa 1.1 1.2 1. 3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 Temperature / ℃ 187.1 190.8 194.2 197.4 200.5 203.4 206.2 208.9 211.4 213.8 In normal production, the water level of cooling water remains basically unchanged, and the steam injection speed fluctuates within a small range. In the process of blocking the pipe, as the water level rises, the cooling water squeezes the space inside the vulcanization pipe. At this time, the steam injection speed needs to be reduced through the preset program control to keep the steam pressure relatively stable.

[0010] Furthermore, the line speed of the rubber-sheathed cable during normal production is calculated by the following formula: v = L / t , In the formula, L is the length of the vulcanization pipeline, t The vulcanization time.

[0011] When the length of the vulcanization pipe is constant, the longer the vulcanization time is, the slower the line speed of the rubber-sheathed cable will be during normal production.

[0012] The curing time is calculated by the following formula: , In the formula, T 0 is the temperature selected for the recipe test, t 0 For T The curing time measured at 0 temperature, T is the temperature during normal production, t is the vulcanization time during normal production, K is the vulcanization temperature coefficient.

[0013] For rubber sleeves of different formulations, the vulcanization time at different temperatures is not the same. Usually, a specific temperature is selected to test its vulcanization time, and then the vulcanization time at other temperatures is obtained by conversion, so as to select the most suitable vulcanization temperature and vulcanization time for a given vulcanization pipe length. The value of K in the formula usually ranges from 1.8 to 2.5. In order to simplify the calculation, it can be taken as 2.

[0014] The embodiment of the present invention also provides a continuous vulcanization extrusion production line, which includes a rubber extrusion device, a vulcanization pipeline and a cooling pipeline connected in sequence; a differential pressure transmitter is provided at the end of the cooling pipeline for measuring water pressure; a remote pressure gauge is provided at the starting end of the vulcanization pipeline for measuring air pressure; the continuous vulcanization extrusion production line also includes a control module, the differential pressure transmitter and the remote pressure gauge are electrically connected to the control module, and the control module can detect changes in air pressure and water pressure. After normal production is completed, the above-mentioned pipe blocking method is executed.

[0015] Furthermore, in other preferred embodiments of the present invention, a cooling water inlet is provided at the end of the cooling pipe, and a cooling water outlet is provided at the starting end of the cooling pipe.

[0016] Furthermore, in other preferred embodiments of the present invention, a steam inlet is provided at the starting end of the vulcanization pipeline, and a steam outlet is provided at the end of the vulcanization pipeline.

[0017] Furthermore, in other preferred embodiments of the present invention, the middle section and the end of the vulcanization pipeline are both provided with remote pressure gauges. The middle section and the end of the vulcanization pipeline are also provided with steam supplementary inlets.

[0018] Furthermore, in other preferred embodiments of the present invention, a water level control valve is provided on the vulcanization pipeline near the rubber extrusion equipment.

[0019] The beneficial effects of the embodiments of the present invention are: The embodiment of the present invention provides a pipe-blocking method for a continuous vulcanization extrusion production line, which maintains the steam pressure unchanged at the end of rubber extrusion, and adds cooling water into the vulcanization pipe, so that the cooling water in the vulcanization pipe gradually spreads to the rubber extrusion equipment, and the spreading speed is consistent with the line speed of the rubber-sheathed cable during normal production; it simulates the movement of the rubber-sheathed cable during normal production through the change of water level, so that the vulcanization time between the various parts of the tail section of the rubber-sheathed cable is basically consistent, thereby improving the problem of uneven vulcanization in the prior art. The embodiment of the present invention also provides a continuous vulcanization extrusion production line, which can be used to perform the above-mentioned pipe-blocking method for a continuous vulcanization extrusion production line, thereby improving the yield of the tail section cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram of a continuous vulcanization extrusion production line provided in Example 3 of the present invention; Figure 2 This is an operation logic diagram of a control module of a continuous vulcanization extrusion production line provided in Example 3 of the present invention.

[0022] Icons: 100-continuous vulcanization extrusion production line; 110-rubber extrusion equipment; 120-vulcanization pipeline; 121-remote pressure gauge; 130-cooling pipeline; 131-differential pressure transmitter. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0024] A continuous vulcanization extrusion production line and a pipe blocking method for the continuous vulcanization extrusion production line according to an embodiment of the present invention are described in detail below.

[0025] The features and performance of the present invention are further described in detail below in conjunction with the embodiments. Example 1

[0026] This embodiment provides a pipe blocking method for a continuous vulcanization extrusion production line, comprising: S1. After testing, a certain rubber compound T 0 = Curing time at 143°C t 0 is 30 min; through conversion, we get T = Curing time at 203°C t The production line speed in a 50m long vulcanization pipeline is 0.4688 min. v = 106.7 m / min.

[0027] S2. During normal production, the line speed of the rubber-sheathed cable is controlled at 106.7 m / min. The steam pressure is maintained at 1.6 ± 0.1Mpa according to the data in Table 1.

[0028] S3. When the rubber extrusion is finished, stop the production line, maintain the steam pressure at 1.6±0.1Mpa through air pressure monitoring, inject cooling water into the vulcanization pipeline, and control the cooling water diffusion speed to 106.7±1m / min by monitoring the water pressure.

[0029] S4. When the cooling water spreads to the rubber extrusion equipment, stop injecting cooling water and steam and stop the vulcanization process.

[0030] S5. After the rubber-sheathed cable has cooled down, drain the cooling water and complete the pipe sealing operation. Example 2

[0031] This embodiment provides a pipe blocking method for a continuous vulcanization extrusion production line, comprising: S1. After testing, a certain rubber compound T 0 = Curing time at 143°C t 0 is 40 min; by conversion, we get T = Curing time at 200°C t The production line speed in the 80m long vulcanization pipeline is 0.7695 min. v = 104.0 m / min.

[0032] S2. During normal production, the line speed of the rubber-sheathed cable is controlled at 104.0 m / min. The steam pressure is maintained at 1.5 ± 0.1Mpa according to the data in Table 1.

[0033] S3. When the rubber extrusion is finished, stop the production line, maintain the steam pressure at 1.5±0.1Mpa through air pressure monitoring, inject cooling water into the vulcanization pipeline, and control the cooling water diffusion speed to 104.0±1m / min by monitoring the water pressure.

[0034] S4. When the cooling water spreads to the rubber extrusion equipment, stop injecting cooling water and steam and stop the vulcanization process.

[0035] S5. After the rubber-sheathed cable has cooled down, drain the cooling water and complete the pipe sealing operation. Example 3

[0036] This embodiment provides a continuous vulcanization extrusion production line 100, which includes a rubber extrusion device 110, a vulcanization pipeline 120 and a cooling pipeline 130 connected in sequence.

[0037] A differential pressure transmitter 131 is provided at the end of the cooling pipe 130 for measuring the water pressure; a remote pressure gauge 121 is provided at the starting end of the vulcanization pipe 120 for measuring the air pressure; the continuous vulcanization extrusion production line 100 also includes a control module, and the differential pressure transmitter 131 and the remote pressure gauge 121 are both electrically connected to the control module. The control module can detect changes in air pressure and water pressure, and execute the above-mentioned pipe sealing method after normal production is completed.

[0038] The control module has two operating modes. In normal production mode, the water level of cooling water is monitored by differential pressure transmitter. If it is higher than the upper limit of the water level, the water inlet is reduced; if it is lower than the lower limit of the water level, the water inlet is increased. In the pipe-blocking mode, the rising speed of the water level is monitored by differential pressure transmitter. If the rising speed is too slow, the water inlet is increased; if the rising speed is too fast, the water inlet is reduced.

[0039] Furthermore, a cooling water inlet is provided at the end of the cooling pipe 130, and a cooling water outlet is provided at the starting end of the cooling pipe 130. Both the cooling water inlet and the cooling water outlet are provided with solenoid valves, which are electrically connected to the control module, and the control module regulates the water inlet and water outlet in real time.

[0040] Furthermore, a steam inlet is provided at the starting end of the vulcanization pipeline 120, and a steam outlet is provided at the end of the vulcanization pipeline 120. Solenoid valves are also provided at the steam inlet and steam outlet, and the control module regulates the air intake and air output in real time to maintain the stability of the air pressure.

[0041] Furthermore, the middle section and the end of the vulcanization pipeline 120 are both provided with a remote pressure gauge 121. Since the vulcanization pipeline is long, the steam will experience pressure decay on the way forward. The remote pressure gauge 121 is provided at the middle section and the end to achieve multi-point air pressure detection, which is more accurate for air pressure monitoring. Optionally, the middle section and the end of the vulcanization pipeline 120 are also provided with a steam supplementary inlet. A solenoid valve is provided at the steam supplementary inlet, which is controlled by the control module to supplement steam at the middle section and the end of the vulcanization pipeline 120 to offset the pressure decay of the steam on the way forward. In addition, as the water level rises, the steam outlet provided at the end of the vulcanization pipeline 120 will be closed, and at this time, the steam supplementary inlet at the middle section and the end of the vulcanization pipeline 120 can be used as a channel for steam discharge in turn, thereby maintaining the stability of the air pressure. The two working modes only need to be switched by setting a three-way valve. Similarly, the steam inlet at the starting end of the vulcanization pipeline 120 may also be provided with a three-way valve. When the water level is about to reach the starting end of the vulcanization pipeline 120 and air intake is no longer needed, the steam inlet may be used in reverse as a channel for steam exhaust.

[0042] Furthermore, a water level control valve is provided near the rubber extrusion equipment 110 in the vulcanization pipeline 120. The water level control valve can limit the maximum height of the water level to prevent the cooling water from overflowing from the head of the rubber extrusion equipment.

[0043] Comparative Example 1 This comparative example provides a pipe-blocking method for a continuous vulcanization extrusion production line, comprising: S1. After testing, a certain rubber compound T 0 = Curing time at 143°C t 0 is 30 min; through conversion, we get T = Curing time at 203°C t The production line speed in a 50m long vulcanization pipeline is 0.4688 min. v = 106.7 m / min.

[0044] S2. During normal production, the line speed of the rubber-sheathed cable is controlled at 106.7 m / min. The steam pressure is maintained at 1.6 ± 0.1Mpa according to the data in Table 1.

[0045] S3. When the rubber extrusion is completed, stop the production line and gradually lower the temperature to room temperature at a rate of 10℃ / min.

[0046] Test example The pipe-blocking method used in Example 1 and Comparative Example 1 was adopted. After the pipe-blocking was completed, samples were taken at one end (end A) of the vulcanization pipe close to the cooling pipe and one end (end B) close to the rubber extrusion equipment. The test was conducted three times in parallel. The collected samples were tested according to the national standard GB / T 2951.11-2008. The test results are shown in Table 2.

[0047] Table 2. Sample sulfide degree test

[0048] It can be seen from Table 2 that the tensile strength of the pipe-blocking method of Example 1 of the present invention at the A end and the B end is basically consistent, reaching 12 N / mm 2 The elongation at break is also basically the same, reaching about 420%, indicating that the degree of vulcanization of the A end and the B end is basically the same. In contrast, using the tube-suffocating method of comparative example 1, the tensile strength of the A end and the B end is similar, and can also reach 10N / mm 2 About, but the difference in elongation at break is obvious. The elongation at break of end A is about 340%, while the elongation at break of end B is about 540%. For tensile strength, as the degree of vulcanization increases, the cross-linking density increases to form a stable three-dimensional network structure between molecular chains. The tensile strength increases significantly with the increase of the degree of vulcanization. After reaching a certain degree, over-vulcanization (over-vulcanization stage) will cause the cross-linking network to be too dense or even degraded, and the tensile strength will decrease instead. The elongation at break basically conforms to the trend of decreasing with the increase of the degree of vulcanization. Combining the two parameters, it can be seen that at the A end, the tensile strength and elongation at break of Comparative Example 1 are lower than those of Example 1, and there is a case of over-vulcanization. At the B end, the tensile strength of Comparative Example 1 is lower than that of Example 1, and the elongation at break is higher than that of Example 1, and there is a case of insufficient vulcanization.

[0049] In summary, the embodiment of the present invention provides a pipe-blocking method for a continuous vulcanization extrusion production line, which maintains the steam pressure unchanged at the end of rubber extrusion, and adds cooling water into the vulcanization pipe, so that the cooling water in the vulcanization pipe gradually spreads to the rubber extrusion equipment, and the spreading speed is consistent with the line speed of the rubber-sheathed cable during normal production; it simulates the movement of the rubber-sheathed cable during normal production through the change of water level, so that the vulcanization time between the various parts of the tail section of the rubber-sheathed cable is basically consistent, thereby improving the problem of uneven vulcanization in the prior art. The embodiment of the present invention also provides a continuous vulcanization extrusion production line, which can be used to perform the above-mentioned pipe-blocking method for a continuous vulcanization extrusion production line, thereby improving the yield of the tail section cable.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pipe-blocking method for a continuous vulcanization extrusion production line, characterized in that: The continuous vulcanization extrusion production line comprises a rubber extrusion device, a vulcanization pipeline and a cooling pipeline connected in sequence; The pipe blocking method comprises: At the end of rubber extrusion, the steam pressure is kept constant, and cooling water is added into the vulcanization pipeline, so that the cooling water in the vulcanization pipeline gradually spreads to the rubber extrusion equipment, and the spreading speed is consistent with the line speed of the rubber sheathed cable during normal production; When the cooling water spreads to the rubber extrusion equipment, the injection of cooling water and steam is stopped, and the cooling water is discharged after the rubber sheathed cable is cooled.

2. The pipe-blocking method for a continuous vulcanization extrusion production line according to claim 1, characterized in that: The spreading speed of the cooling water is calculated by monitoring the rising speed of the water pressure at the end of the cooling pipe, and the injection speed of the cooling water is adjusted by comparing the spreading speed with the line speed of the rubber-sheathed cable during normal production.

3. The pipe blocking method for a continuous vulcanization extrusion production line according to claim 2, characterized in that: The steam pressure is obtained by monitoring the air pressure at the starting end of the vulcanization pipeline, and the steam injection speed is adjusted by the change of the air pressure.

4. The pipe blocking method for a continuous vulcanization extrusion production line according to claim 3, characterized in that: During normal production, the line speed of the rubber-sheathed cable is calculated by the following formula: v = L / t ， In the formula, L is the length of the vulcanization pipeline, t The vulcanization time.

5. The pipe blocking method for a continuous vulcanization extrusion production line according to claim 4, characterized in that: The curing time is calculated by the following formula: ， In the formula, T 0 is the temperature selected for the recipe test, t 0 For T The curing time measured at 0 temperature, T is the temperature during normal production, t is the vulcanization time during normal production, K is the vulcanization temperature coefficient.

6. A continuous vulcanization extrusion production line, characterized in that: The invention comprises a rubber extrusion device, a vulcanization pipeline and a cooling pipeline which are connected in sequence; a differential pressure transmitter is arranged at the end of the cooling pipeline for measuring water pressure; a remote pressure gauge is arranged at the starting end of the vulcanization pipeline for measuring air pressure; the continuous vulcanization extrusion production line also comprises a control module, the differential pressure transmitter and the remote pressure gauge are both electrically connected to the control module, the control module can detect the changes of air pressure and water pressure, and after the normal production is completed, the pipe blocking method as described in any one of claims 1 to 5 is executed.

7. The continuous vulcanization extrusion production line according to claim 6, characterized in that: The end of the cooling pipeline is provided with a cooling water inlet, and the starting end of the cooling pipeline is provided with a cooling water outlet.

8. The continuous vulcanization extrusion production line according to claim 7, characterized in that: The starting end of the vulcanization pipeline is provided with a steam inlet, and the end of the vulcanization pipeline is provided with a steam outlet.

9. The continuous vulcanization extrusion production line according to claim 8, characterized in that: The middle section and the end of the vulcanization pipeline are both provided with remote pressure gauges, and the middle section and the end of the vulcanization pipeline are also provided with steam supplementary inlets.

10. The continuous vulcanization extrusion production line according to claim 1, characterized in that: The vulcanization pipeline is provided with a water level control valve near the rubber extrusion equipment.

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