Refractory material expansion adjusting system and method for molten glass flowing channel

Abstract

The invention belongs to the field of substrate glass manufacturing, and particularly relates to an expansion adjusting system and method for a refractory material of a molten glass flowing channel. A jacking mechanism is installed on the periphery of the refractory material, and automatic adjustment of the jacking mechanism is achieved through a pressure sensor and a jacking air cylinder; controllable and orderly expansion and inclination adjustment of the refractory material on the periphery of the channel are guaranteed, so that the platinum channel and the refractory material are always in an attached state, and the problem of extrusion deformation caused by untimely expansion adjustment of the channel and the refractory material is effectively solved; meanwhile, the risk that the local surface of the channel is volatilized and swelled due to separation of platinum and a refractory material caused by over-adjustment or inconsistent adjustment of the channel and the refractory material is reduced, and the service life of the channel is prolonged. The pre-tightening and expansion adjustment of the channel refractory material is realized through the tightening mechanism, the adjustment process is simplified, and the adjustment is more accurate, so that the operation stability of the channel is ensured, and meanwhile, the danger caused by the adjustment operation of personnel in a high-temperature environment is reduced.

Description

Technical Field

[0001] The invention belongs to the field of substrate glass manufacturing, and in particular relates to a refractory material expansion adjustment system and method for a glass liquid circulation channel. Background Art

[0002] The glass liquid circulation channel is the core equipment in the production of liquid crystal glass substrates and plays a vital role in product quality. From a technical point of view, it is the channel for the transmission of glass liquid, responsible for transferring the glass liquid in the pool furnace to the molding process. In this process, it also undertakes the process functions of clarification, homogenization, temperature control, flow control, etc.

[0003] Since refractory materials are arranged on the periphery of the channel and the refractory materials are arranged close to the platinum, during the heating process of the line, as the temperature continues to rise, the channel and the refractory materials will expand. During the expansion process, the peripheral refractory materials must synchronously move along the expansion direction of the platinum channel to ensure that the internal platinum channel is not squeezed and deformed by the refractory materials, so as to ensure the stability of the channel operation; at the same time, the refractory materials and the platinum must always be kept close to each other, otherwise the disordered expansion of the refractory materials in the channel during the heating process may cause the refractory materials to partially separate from the platinum body, resulting in a spatial atmosphere of oxygen on the surface of the platinum, accelerating the volatilization of the platinum surface; at the same time, the local space will cause the platinum surface to have no refractory support. When the glass liquid comes, it may cause local bulging of the platinum channel, affecting the safe operation of the platinum.

[0004] At present, the production line uses manual mechanical adjustment of the expansion of the channel refractory materials. Due to the limitations of the operator's technical level and experience, it is impossible to make more precise adjustments. Insufficient adjustment may lead to extrusion and deformation of the platinum channel, over-adjustment or inconsistent adjustment may cause the platinum to separate from the refractory materials, increasing the risk of local volatilization and bulging on the platinum surface. Summary of the invention

[0005] In view of the technical problems in the prior art of channel deformation caused by separation from refractory materials during channel expansion and low precision in channel expansion adjustment, the present invention provides a system and method for adjusting the expansion of refractory materials in a glass liquid circulation channel.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A refractory material expansion adjustment system for a glass liquid circulation channel is characterized in that it includes a channel and a tightening mechanism, refractory material is arranged on the outside of the channel, the tightening mechanism includes a pressure plate and a tightening cylinder, the tightening cylinder is vertically arranged on the pressure plate, a pressure sensor is installed on the pressure plate, and the pressure plate is fixed to the outside of the refractory material at one end of the channel.

[0008] The refractory material includes a first refractory material and a second refractory material. A bottom steel structure is fixed at the bottom of the second refractory material. Four tightening mechanisms are evenly fixed on the bottom steel structure in a group. The columns are vertically fixed on the bottom steel structure. A transverse supporting steel structure is arranged on the columns, and the transverse supporting steel structure is connected to the tightening mechanism.

[0009] A buffer layer is arranged on the outer side of the second refractory material at one end of the channel connection pressing mechanism, and the buffer layer is fixedly connected to the pressing plate.

[0010] The tightening mechanism is also connected to a control system, which includes a data acquisition module, a data processing module and a system adjustment module.

[0011] A data acquisition module, used to collect data monitored by the pressure sensor;

[0012] A data processing module is used to process the data collected by the data acquisition module to determine whether the channel refractory material needs to be adjusted. If adjustment is required, the actual value of the expansion adjustment is calculated based on the pre-tightening pressure value;

[0013] The system adjustment module is used to convert the actual value of the expansion adjustment into an electrical signal and adjust the pressure of the tightening mechanism according to the electrical signal.

[0014] A temperature sensor is installed on the channel, and the temperature sensor is connected to a data acquisition module. The data acquisition module is used to collect temperature data monitored by the temperature sensor.

[0015] A signal processor is installed on the tightening cylinder, and the signal processor receives the electrical signal from the system adjustment module and adjusts the tightening cylinder according to the electrical signal.

[0016] A method for regulating the expansion of refractory materials in a glass liquid circulation channel, wherein the control system is provided with a pressure threshold value P1 and a pre-tightening pressure value P0, P1>P0, and when the channel expands due to heat, when the pressure value P monitored by the pressure sensor is greater than or equal to the pressure threshold value P1, the tightening cylinder is regulated to move outward, and the pressure plate moves outward accordingly, until the pressure value P returns to the pre-tightening pressure value P0.

[0017] The tightening mechanism is connected to a control system, which includes a data acquisition module, a data processing module and a system adjustment module. The expansion adjustment method includes the following steps:

[0018] Step 1: The data acquisition module continuously acquires the temperature data T and pressure value P monitored by the temperature sensor and the pressure sensor within a time t;

[0019] Step 2: The control system 3 is provided with an expansion threshold δ1, and the data processing module calculates the real-time expansion δ according to the temperature data T collected by the data acquisition module. When the pressure value P≥P1 and the expansion δ≥δ1, it is judged that the channel refractory material needs to be expanded and adjusted; the actual value P2 of the expansion adjustment is calculated according to the pre-tightening pressure value P0, and the actual value P2 of the expansion adjustment is sent to the system adjustment module;

[0020] Step 3: The system adjustment module converts the actual value P2 of the expansion adjustment into an electrical signal and sends it to the signal processor;

[0021] Step 4: The signal processor adjusts each group of tightening cylinders according to the electrical signal until the value monitored by the pressure sensor returns to the pre-tightening pressure P0.

[0022] The calculation method of the real-time expansion amount δ is: δ = f (γ1, γ2, T);

[0023] Wherein, δ is the expansion at temperature T; T is the temperature data; γ1 and γ2 are the expansion coefficients of the first refractory material and the second refractory material respectively.

[0024] In step 4, as long as one of the pressure sensors in each group of the pressing mechanism is restored to the pre-pressing pressure P0, when the value of the pressure sensor in a group is not restored to the pre-pressing pressure, the average value P of the pressure sensors in the pressing mechanism of the group is taken. 01 , and then restore the value of the pressure sensor in the tightening mechanism to the average value P 01 , and the average value P 01 It replaces the pre-tightening pressure P0 and becomes the new pre-tightening pressure value.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention discloses a refractory material expansion regulating system for a glass liquid circulation channel. Through a pressure sensor installed on a pressure plate, the system can monitor the pressure changes generated during the expansion of the refractory material in real time. When the pressure reaches the set threshold, the tightening cylinder automatically adjusts to move the pressure plate, thereby accurately controlling the expansion space of the refractory material, avoiding the separation between the refractory material and the channel wall due to uneven expansion or excessive expansion, and effectively preventing the formation of bulges. The design of fixing the pressure plate on the outside of the refractory material, combined with the dynamic response capability of the tightening cylinder, can effectively restrain the expansion of the refractory material, prevent structural instability or local damage caused by uneven distribution of expansion force, thereby ensuring the long-term stable operation of the channel under high-temperature working conditions.

[0027] Furthermore, the fixed connection between the second refractory material and the fixed steel structure enhances the stability of the entire refractory layer, ensuring that the expansion of the refractory material at high temperature will not cause overall displacement, effectively preventing structural loosening and bulging caused by uneven expansion. The tightening mechanisms are evenly distributed on the fixed steel structure in groups of four. This layout can ensure that the pressure applied to the refractory material is uniform, avoiding excessive or insufficient local pressure, thereby reducing the risk of uncontrolled expansion and bulging caused by uneven pressure distribution.

[0028] Furthermore, the presence of the buffer layer can effectively absorb the additional pressure and impact force generated by the thermal expansion of the refractory material, reduce the force directly acting on the refractory material and the channel structure, avoid material damage or structural deformation due to force concentration, and thus reduce the possibility of bulge formation.

[0029] Furthermore, the tightening mechanism is connected to the control system. Through the integrated data acquisition, processing and adjustment modules, the system can monitor the expansion and temperature changes of the refractory materials in the channel in real time, and automatically adjust the tightening cylinder to ensure that the expansion of the refractory materials is precisely controlled, effectively avoiding uncontrolled expansion caused by untimely or inaccurate manual adjustment.

[0030] Furthermore, the connection between the data acquisition module and the temperature sensor and pressure sensor enables the system to integrate temperature and pressure data and more accurately determine the real-time expansion state of the refractory material through algorithm processing. When the temperature rises and the expansion pressure increases, the system can respond quickly and adjust the tightening cylinder in time to avoid bulging problems caused by uneven expansion.

[0031] Furthermore, the data acquisition module continuously monitors the data of the pressure sensor and the temperature sensor, realizing real-time monitoring of the working status of the channel. When abnormal changes in temperature or pressure are detected, indicating that the refractory material may face the risk of excessive or insufficient expansion pressure, the system can respond quickly. The data processing module performs intelligent analysis based on the collected data, determines whether the refractory material needs expansion adjustment, and calculates the precise adjustment value. This dynamic calculation based on real-time data ensures fine control of the expansion process, effectively prevents the separation between the refractory material and the channel wall caused by uneven expansion or excessive expansion, thereby avoiding the formation of bulges. The system adjustment module can convert the calculated actual value of the expansion adjustment into an electrical signal, instantly adjust the movement of the tightening cylinder, and realize active control of the expansion of the refractory material. At the same time, it can also dynamically adjust the pre-tightening pressure value according to the data monitored by the current pressure sensor. This adaptive adjustment mechanism allows the system to continuously maintain the best working state and further reduce the risk of bulging.

[0032] Furthermore, the present invention discloses a method for regulating the expansion of refractory materials in a glass liquid circulation channel. By setting a pressure threshold and a pre-tightening pressure value, the system can automatically monitor pressure changes and start the regulating mechanism when the pressure value is greater than or equal to the pressure threshold, ensuring that the pressure is restored to the pre-tightening pressure in time. This dynamic response mechanism significantly improves the accuracy of expansion control and avoids the risk of bulging caused by premature or late adjustment.

[0033] Furthermore, by combining temperature data and expansion threshold, the system can determine whether expansion adjustment is needed based on the actual expansion. This method is based on material properties and real-time working conditions, improves the scientificity and accuracy of judgment, avoids unnecessary adjustment actions, and improves the pertinence and effectiveness of adjustment.

[0034] Furthermore, by converting the actual value of the expansion adjustment into an electrical signal to adjust the tightening cylinder, the pressure value can be accurately restored to the preset value. This closed-loop feedback adjustment mechanism maintains the dynamic balance of the system pressure, reduces the potential risk of uneven expansion, and effectively prevents the formation of bulges.

[0035] Furthermore, when the values ​​of the pressure sensors in a certain group of tightening mechanisms fail to fully recover to the pre-tightening pressure values, a strategy is adopted to take the average value and adjust it to that value. This not only solves the problem of uneven adjustment caused by deviations in individual sensor readings, but also ensures the balance of the expansion of the refractory materials in the entire channel by continuously refreshing the pre-tightening pressure values, thereby further improving the accuracy of adjustment and the stability of the channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the front view of the structure of the expansion adjustment system of the refractory material of the substrate glass channel;

[0037] Figure 2 It is a top view of the structure of the expansion adjustment system of the refractory material of the substrate glass channel;

[0038] Figure 3 Flow chart of the expansion adjustment system for the refractory material of the substrate glass channel.

[0039] Numbers: 1-1, channel; 1-2: first refractory material; 1-3, second refractory material; 1-41, bottom steel structure; 1-42, column; 1-43, lateral support steel structure; 2-1, pressure plate; 2-2, pressure sensor; 2-3, tightening cylinder; 2-4, signal processor; 3, control system; 5, temperature sensor. DETAILED DESCRIPTION

[0040] In order to further understand the content of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0041] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] See also Figure 1 , Figure 2 and Figure 3 A refractory expansion adjustment system structure for a glass liquid circulation channel includes a channel 1-1 and a tightening mechanism. A temperature sensor 5 is installed on the surface of the channel 1-1. A first refractory material 1-2 and a second refractory material 1-3 are arranged on the outside of the channel 1-1 in sequence. A bottom steel structure 1-41 is fixed to the lower part of the second refractory material 1-3. A column 1-42 is vertically fixed on the bottom steel structure 1-41. A transverse support steel structure 1-43 is arranged on the column 1-42. The transverse support steel structure 1-43 is connected to a tightening cylinder 2-3 of the tightening mechanism. The tightening mechanism includes a pressing plate 2-1 and a tightening cylinder 2-3. The tightening cylinder 2-3 is vertically fixed on the pressing plate 2-1. A pressure sensor 2-2 is installed on the pressing plate 2-1. The pressing plate 2-1 is fixed to the outside of the refractory material at one end of the channel 1-1. ; A signal processor 2-4 is installed on the deposit cylinder 2-3 of the tightening mechanism, and the tightening mechanism is connected to the control system 3; the control system includes a data acquisition module 301, a data processing module 302 and a system adjustment module 303, the data acquisition module 301 is used to collect data monitored by the pressure sensor 2-2 and the temperature sensor 5; the data processing module 302 is used to process the data collected by the data acquisition module 301 to determine whether the channel refractory material needs to be adjusted, and if adjustment is required, the actual expansion adjustment value is calculated based on the pre-tightening pressure value; the system adjustment module 303 is used to convert the actual expansion adjustment value into an electrical signal and send it to the signal processor 4-4 of the tightening mechanism, and complete the refresh setting of the pre-tightening pressure value based on the data monitored by the pressure sensor 2-2.

[0043] This embodiment provides a system and method for adjusting the expansion of refractory materials in a glass liquid circulation channel. The system is designed to manage the expansion of refractory materials in a glass liquid circulation channel under high temperature conditions to ensure the stability of the channel structure. The specific implementation steps are as follows:

[0044] The channel 1-1 is made of high temperature resistant alloy material, and is used to transport high temperature molten glass. The outer side of the channel is covered with a first refractory material 1-2 and a second refractory material 1-3, wherein the bottom of the second refractory material 1-3 is fixed by a bottom steel structure 1-41 to enhance structural support. A column 1-42 is vertically arranged on the bottom steel structure 1-4, and a transverse support steel structure 1-43 is arranged on the column 1-42. The tightening mechanism is connected to the channel 1-1 through the transverse support steel structure 1-43. The tightening mechanisms are grouped into four, and each group of tightening mechanisms is evenly distributed and connected to the channel 1-1 through the transverse support steel structure 1-43. Each tightening mechanism includes a pressing plate 2-1 and a tightening cylinder 2-3. A pressure sensor 2-2 is installed on the pressing plate 2-1 to monitor the expansion pressure. The pressing plate 2-1 is fixed to the outside of the refractory material at one end of the channel 1-1; a temperature sensor 5 is installed on the surface of the channel 1-1, and the tightening mechanism is connected to a control system 3. The control system 3 includes a data acquisition module 301, a data processing module 302 and a system adjustment module 303. The data acquisition module 301 is connected to the temperature sensor 5 and the pressure sensor 2-2 to collect the pressure value P and the temperature data T in real time; the control system 3 is preset with a pressure threshold value P1, an expansion threshold value δ1 and a pre-tightening pressure value P0,

[0045] The data processing module 302 calculates the real-time expansion amount δ based on the temperature data T collected by the data acquisition module 301. When the pressure value P≥P1 and the expansion amount δ≥δ1, it is determined that the channel refractory material needs to be expanded. Otherwise, no expansion adjustment is performed. The data processing module 302 calculates the actual expansion adjustment value P2 based on the pre-tightening pressure value P0, and sends the actual expansion adjustment value P2 to the system adjustment module 303. The system adjustment module 303 converts the actual expansion adjustment value P2 into an electrical signal and sends it to the signal processor 4-4. The signal processor 4-4 adjusts each group of tightening cylinders 2-3 according to the electrical signal until the value monitored by the pressure sensor 2-2 returns to the pre-tightening pressure P0.

[0046] When the system is running, the data acquisition module 301 continuously records the temperature T and pressure P within the time t. Assume that at a certain moment t = 10 minutes, the temperature T = 1200 ° C and the pressure P = 50 MPa; the data processing module 302 calculates the expansion amount δ = f (γ1, γ2, T) at the temperature T according to the temperature T, where δ is the expansion amount at the temperature T, in mm; T is the temperature data, in ° C; γ1 and γ2 are the expansion coefficients of the first refractory material and the second refractory material respectively; Assume that γ1 = 2 × 10^-6 / °C, γ2 = 3 × 10^-6 / °C, the calculated expansion amount δ exceeds the preset expansion amount threshold δ1, and the pressure P also reaches the pressure threshold P0. At this time, the system determines that expansion adjustment is required.

[0047] The system adjustment module 303 calculates the actual expansion adjustment value P2, assuming it is 55MPa, and converts this value into an electrical signal and sends it to the signal processor 2-4. The signal processor 2-4 then controls the tightening cylinder 2-3 to adjust the cylinder so that the pressure plate 2-1 moves outward until the pressure value monitored by the pressure sensor (2-2) returns to the pre-tightening pressure P0.

[0048] In a certain group of tightening mechanisms, if the values ​​of all pressure sensors 2-2 have not completely recovered to P0, and there are one or several pressure sensors 2-2 whose pressure values ​​have not recovered to P0, the data processing module 302 calculates the average value P of these values. 01 , such as P 01 =50.5MPa, then adjust the values ​​of all pressure sensors 2-2 to P 01 , and P 01 Set the new pre-tightening pressure value P0 to ensure the uniformity of the expansion of the channel refractory material.

[0049] The system and method described above demonstrate how to efficiently and accurately manage the expansion of refractory materials in the glass liquid circulation channel, avoid the risk of bulging due to uneven expansion, and ensure the continuity and safety of the production process.

[0050] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A refractory material expansion adjustment system for a glass liquid circulation channel, characterized in that: The invention comprises a channel (1-1) and a tightening mechanism. The channel (1-1) has a refractory material on the outside. The tightening mechanism comprises a pressing plate (2-1) and a tightening cylinder (2-3). The tightening cylinder (2-3) is vertically arranged on the pressing plate (2-1). A pressure sensor (2-2) is installed on the pressing plate (2-1). The pressing plate (2-1) is fixed on the outside of the refractory material at one end of the channel (1-1).

2. A refractory material expansion adjustment system for a glass liquid flow channel according to claim 1, characterized in that: The refractory material comprises a first refractory material (1-2) and a second refractory material (1-3); a bottom steel structure (1-41) is fixed to the lower part of the second refractory material (1-3); four tightening mechanisms are evenly fixed on the bottom steel structure (1-41) in a group; a column (1-42) is vertically fixed on the bottom steel structure (1-41); a transverse supporting steel structure (1-43) is arranged on the column (1-42); and the transverse supporting steel structure (1-43) is connected to the tightening mechanism.

3. A refractory material expansion adjustment system for a glass liquid flow channel according to claim 2, characterized in that: A buffer layer (4) is arranged on the outside of the second refractory material (1-3) connected to one end of the tightening mechanism of the channel (1-1), and the buffer layer (4) is fixedly connected to the pressing plate (2-1).

4. The refractory material expansion adjustment system for a glass liquid flow channel according to claim 1, characterized in that: The tightening mechanism is also connected to a control system (3), and the control system (3) includes a data acquisition module (301), a data processing module (302) and a system adjustment module (303). A data acquisition module (301), used for acquiring data monitored by the pressure sensor (2-2); A data processing module (302) is used to process the data collected by the data collection module (301) to determine whether the channel refractory material needs to be adjusted, and if adjustment is required, to calculate the actual value of the expansion adjustment according to the pre-tightening pressure value; The system adjustment module (303) is used to convert the actual value of the expansion adjustment into an electrical signal and adjust the pressure of the tightening mechanism according to the electrical signal.

5. A refractory material expansion adjustment system for a glass liquid flow channel according to claim 4, characterized in that: A temperature sensor (5) is installed on the channel (1-1); the temperature sensor (5) is connected to a data acquisition module (301); and the data acquisition module (301) is used to collect temperature data monitored by the temperature sensor (5).

6. A refractory material expansion adjustment system for a glass liquid flow channel according to claim 4, characterized in that: A signal processor (2-4) is installed on the tightening cylinder (2-3), and the signal processor (2-4) receives an electrical signal from a system adjustment module (303) and adjusts the tightening cylinder (2-3) according to the electrical signal.

7. A method for adjusting the expansion of refractory materials in a glass liquid circulation channel, characterized in that: A refractory material expansion regulating system for a precious metal channel for glass liquid circulation according to any one of claims 1 to 6, wherein the regulating method is as follows: the control system (3) is provided with a pressure threshold value P1 and a pre-tightening pressure value P0, P1>P0, and when the channel (1-1) expands due to heat, when the pressure sensor (2-2) monitors that the pressure value P is greater than or equal to the pressure threshold value P1, the tightening cylinder (2-3) is regulated to move outward, and the pressure plate (2-1) moves outward accordingly, until the pressure value P returns to the pre-tightening pressure value P0.

8. A method for adjusting the expansion of refractory materials in a glass liquid flow channel according to claim 7, characterized in that: The tightening mechanism is connected to a control system (3), the control system (3) comprises a data acquisition module (301), a data processing module (302) and a system adjustment module (303), and the expansion adjustment method comprises the following steps: Step 1: The data acquisition module (301) continuously acquires temperature data T and pressure value P monitored by the temperature sensor (5) and the pressure sensor (2-2) within a time period t; Step 2: The control system (3) is provided with an expansion threshold value δ1, and the data processing module (302) calculates the real-time expansion amount δ according to the temperature data T collected by the data collection module (301); when the pressure value P≥P1 and the expansion amount δ≥δ1, it is determined that the channel refractory material needs to be expanded and adjusted; the actual expansion adjustment value P2 is calculated according to the pre-tightening pressure value P0, and the actual expansion adjustment value P2 is sent to the system adjustment module (303); Step 3: The system adjustment module (303) converts the actual value P2 of the expansion adjustment into an electrical signal and sends it to the signal processor (4-4); Step 4: The signal processor (4-4) adjusts each group of tightening cylinders (2-3) according to the electrical signal until the value monitored by the pressure sensor (2-2) returns to the pre-tightening pressure P0.

9. A method for adjusting the expansion of refractory materials in a glass liquid circulation channel according to claim 7, characterized in that: The calculation method of the real-time expansion amount δ is: δ = f (γ1, γ2, T); Wherein, δ is the expansion at temperature T; T is the temperature data; γ1 and γ2 are the expansion coefficients of the first refractory material and the second refractory material respectively.

10. A method for adjusting the expansion of refractory materials in a glass liquid circulation channel according to claim 7, characterized in that: In the step 4, it is sufficient if at least one of the values ​​of the pressure sensors (2-2) in each group of the pressing mechanisms is restored to the pre-pressing pressure P0. When the value of the pressure sensors (2-2) in a group is not restored to the pre-pressing pressure, the values ​​of the pressure sensors (2-2) in the pressing mechanisms of the group are averaged P. 01 , and then restore the value of the pressure sensor (2-2) in the tightening mechanism to the average value P 01 , and the average value P 01 It replaces the pre-tightening pressure P0 and becomes the new pre-tightening pressure value.

Images