Low-pressure blasting blanking cap for spray pipe and preparation method of low-pressure blasting blanking cap

Abstract

The invention discloses a low-pressure blasting blanking cap for a spray pipe and a preparation method of the low-pressure blasting blanking cap. The method comprises the following steps that S1, raw materials are prepared; s2, refining the composite rubber to obtain sheets; s3, the composite rubber sheet is sheared; s4, pretreating the clamping cloth and shearing; s5, mold preheating; s6, filling materials; s7, mold closing and temperature rising; s8, pressurizing and exhausting; s9, vulcanizing; s10, opening the mold; s11, cooling is conducted; and S12, the first workpiece is subjected to air pressure blasting. The composite rubber and the pretreated clamping cloth are integrally vulcanized and formed to form the low-pressure blasting blanking cap, large-batch machining and production of the low-pressure blasting blanking cap can be efficiently completed, and each piece is high in size precision, stable in quality and excellent in consistency.

Description

Technical Field

[0001] The invention relates to the technical field of plugging caps, and in particular to a low-pressure blasting plugging cap for a nozzle and a preparation method thereof. Background Art

[0002] The plugging cap of the nozzle of a solid rocket engine is generally bonded to the nozzle gas channel to form a seal for the nozzle and the inner cavity of the combustion chamber. Its main function is to prevent moisture inside the engine and to establish a stable initial pressure when the engine is ignited, so that the engine can be ignited smoothly. At present, the nozzle low-pressure blasting plugging cap is usually made of ordinary rubber-cloth products when the blasting value is lower than 1MPa, and is usually machined from aluminum alloy materials when the blasting value is higher than 1MPa.

[0003] With the continuous demand for flight power and the improvement of load performance of model products, more requirements are also put forward for engine performance. Lightweight and high load are the new requirements for current engine research and innovation. When the plugging cap with a low-pressure burst value higher than 1MPa of the traditional nozzle is machined and bonded with aluminum alloy materials, the flexible plugging cap is bonded to the nozzle after applying glue on the bonding surface of the plugging cap and the corresponding bonding surface of the inner wall of the nozzle, and a tool is placed on the plugging cap to pressurize and cure the bonding surface. It is easy to produce a leakage channel at the part where the plugging cap and the nozzle are not well fitted, resulting in leakage on the bonding surface of the plugging cap, affecting the normal operation of the engine.

[0004] In order to overcome the problem of air leakage after bonding of a plugging cap with a burst value higher than 1MPa formed by machining of aluminum alloy materials, the present invention adopts a composite rubber and pre-treated cloth sandwich molding method to prepare a plugging cap with a burst value higher than 1MPa, which is used for the manufacture of solid rocket engine nozzle parts. It has good processability and low manufacturing cost, and the molded products have good bonding strength, light weight and other comprehensive excellent properties. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned background technology and provide a low-pressure blasting plugging cover for a nozzle and a preparation method thereof. The method comprises vulcanizing and integrally forming a composite rubber and a pretreated sandwich cloth into a low-pressure blasting plugging cover. The prepared plugging cover has a blasting value higher than 1MPa, which can improve the bonding strength between the composite rubber and the pretreated sandwich cloth and the bonding fit of the nozzle, thereby solving the problem of air leakage in the nozzle bonding plugging cover.

[0006] To achieve the above object, the present invention provides a method for preparing a low-pressure blasting plugging cap for a nozzle, comprising the following steps:

[0007] S1: Prepare raw materials: the raw materials include composite rubber and pre-treated interlayer cloth, and the composite rubber is mixed to form a mixed rubber sheet;

[0008] S2: Compound rubber is refined into sheets: the sheets are rolled out on an open mixing mill, each section of the mixed rubber sheet is filled with materials and then triangularly packaged, and then thinned out to obtain compound rubber sheets;

[0009] S3: Shearing of composite rubber sheet: Take two layers of composite rubber sheets, mark them, shear them and weigh them to obtain the sheared composite rubber sheets;

[0010] S4: Pre-treated interlayer fabric cutting: Take a layer of pre-treated interlayer fabric, mark it first and then cut it into shape to obtain the pre-treated interlayer fabric after cutting;

[0011] S5: Mold preheating: Check the mold and vulcanizer, and place the mold on the vulcanizer heating plate for preheating;

[0012] S6: Filling: filling the sheared composite rubber sheet and pre-treated sandwich cloth into the mold cavity;

[0013] S7: Mold closing and heating: Push the mold steadily onto the vulcanizer platform, the pressure center of the mold coincides with the pressure center of the vulcanizer, and the temperature is raised randomly;

[0014] S8: Pressurization and exhaust: pressurization is carried out in a step-by-step manner, and exhaust is performed at the same time to eliminate the air in the mold cavity;

[0015] S9: Vulcanization: The composite rubber and pre-treated interlayer fabric are vulcanized and formed into one piece;

[0016] S10: mold opening: after vulcanization, the mold is taken out and moved to the working platform, and the mold is opened to take out the vulcanized integrally formed plug cover;

[0017] S11: Cooling: naturally cooling the vulcanized integrally formed plugging and capping product to room temperature after demoulding;

[0018] S12: First piece gas pressure blasting: The first piece of each batch of plugging cap products is used for gas pressure blasting test. The blasting pressure is between 1.6MPa and 2.0Mpa, and the low-pressure blasting plugging cap for nozzle is obtained.

[0019] Further, in step S1, the composite rubber comprises the following components by weight: 100 parts of primary smoked sheet rubber, 5-8 parts of zinc oxide, 1.5-3 parts of stearic acid, 3-5 parts of sulfur, 1.2-3 parts of accelerator, 0.7-1.5 parts of antioxidant, 1.5-3 parts of antioxidant, 20-25 parts of white carbon black, 1.5-3 parts of paraffin wax, and 1.7-3 parts of adhesive;

[0020] The mixed rubber sheets made of the composite rubber are stacked in layers, with cotton cloth placed between two adjacent layers, and the number of stacked layers does not exceed 4;

[0021] The pre-treated sandwich cloth is made of nylon cloth with adhesive coated on its surface, and after drying, a dry coating is formed on the surface, and the coating is evenly distributed.

[0022] Furthermore, in step S1, the composite rubber includes the following components by weight: 100 parts of primary smoked sheet rubber, 5 parts of zinc oxide, 1.5 parts of stearic acid, 3 parts of sulfur, 1.2 parts of accelerator, 0.7 parts of antioxidant, 1.5 parts of antioxidant, 20 parts of white carbon black, 1.5 parts of paraffin, and 1.7 parts of adhesive.

[0023] Furthermore, in the step S2, the weight of each section of the mixed film is ≤5Kg, the thickness of the film after the thin-film processing is 2.0mm-2.5mm, and the static time of the film after the film is produced is ≥4h.

[0024] Furthermore, in step S3, the sheared composite rubber sheet is two identical layers of rubber sheets, with an outer diameter of φ250 mm to φ280 mm, a plurality of notches are cut on the composite rubber sheet, and the total weight is 300 g to 350 g;

[0025] Furthermore, in step S5, the mold and the vulcanizer are checked to ensure that the parallelism of the upper and lower working platforms is not greater than 0.40 mm; the preheating temperature is 135° C. to 145° C., and the preheating time is 20 min to 40 min.

[0026] Furthermore, in step S6, first a layer of composite rubber sheet is placed in the lower mold cavity, then a layer of pretreated cloth is placed thereon, and finally a layer of composite rubber sheet is placed on the pretreated cloth, the pretreated cloth is fixed with an upper mold fixing ring, and the centers of the composite rubber sheet and the pretreated cloth coincide with the center of the mold.

[0027] Furthermore, in the step S8, firstly, the pressure is increased to 6MPa~7MPa, and then the pressure is released; then the pressure is increased to 8MPa~9MPa, and then the pressure is released; then the pressure is increased to 10MPa~11MPa, and then the pressure is released; finally, the pressure is increased to 11MPa~12MPa; the number of exhaust times is not less than 3 times, so as to eliminate the air in the mold cavity; the pressurization and exhaust time does not exceed 2min.

[0028] Furthermore, in step S9, the temperature of the upper and lower platforms of the vulcanizer is 135° C. to 145° C., the pressure is 9 MPa to 13 MPa, and the temperature and pressure are maintained for 30 min to 35 min.

[0029] Furthermore, in step S11, the gas pressure blasting test is specifically to install the vulcanized integrally formed plugging cover on a blasting fixture, introduce nitrogen gas for pressure-increasing blasting, and control the time from the start of inflation to blasting to be between 1.5 minutes and 2 minutes, and the blasting pressure is between 1.6 MPa and 2.0 MPa.

[0030] The present invention also provides a low-pressure blasting plugging cover for a nozzle, which is vulcanized and formed as a whole by composite rubber and pre-treated cloth. The low-pressure blasting plugging cover for a nozzle is prepared by the above-mentioned preparation method of the low-pressure blasting plugging cover for a nozzle; after the low-pressure blasting plugging cover for a nozzle is bonded and cured to the nozzle, it can withstand a pressure of 1.6MPa to 2.0Mpa.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] First, the present invention can solve the bottleneck that the existing nozzle bonding plugging cap with a burst value higher than 1MPa is still formed by aluminum alloy machining, and the plugging cap has poor fit with the nozzle after bonding and leaks. The present invention provides a low-pressure bursting plugging cap that can be vulcanized and molded in one piece of composite rubber and pre-treated cloth and can be processed in batches with high efficiency and light weight.

[0033] Secondly, the present invention utilizes composite rubber and pre-treated cloth for integrated vulcanization molding, which is characterized in that composite rubber with excellent performance as the main body and pre-treated cloth are vulcanized to replace aluminum alloy metal parts plugging cover, thereby achieving the goal of excellent engine bonding and lightweight manufacturing. The composite rubber plugging cover is only 72% of the weight of the aluminum alloy metal flange, reducing the weight of the plugging cover by more than 28%.

[0034] Thirdly, the present invention adopts composite rubber and pre-treated cloth to be integrally vulcanized and molded into a low-pressure blasting plugging cover, which can efficiently complete the processing and production of large quantities of low-pressure blasting plugging covers, and each piece has high dimensional accuracy, stable quality and excellent consistency.

[0035] Fourthly, the present invention uses composite rubber and pre-treated sandwich cloth to form a vulcanized plug cover, which has an advanced preparation process, a simple process flow, and a high material utilization rate, which not only reduces production costs but also shortens production cycles. This method belongs to the technical field of composite rubber vulcanization molding processing and has a good application prospect in the shell power manufacturing in the aerospace field. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a structural schematic diagram of a low-pressure blasting plugging cover for a nozzle of the present invention;

[0037] Figure 2 A schematic diagram of a gas pressure blasting fixture for low pressure blasting plugging;

[0038] In the figure: plug cover 1, blasting fixture 2, plug 3. DETAILED DESCRIPTION

[0039] The implementation of the present invention is described in detail below in conjunction with implementation cases, but they do not constitute a limitation of the present invention and are only given as examples. At the same time, it will become clearer and easier to understand by explaining the advantages of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] The composite rubber and pre-treated cloth are integrally vulcanized and molded to prepare a nozzle low-pressure blasting plugging cover with a specification of height 50mm (height) × φ320mm (outer circle).

[0042] A low-pressure blasting plugging cover for a nozzle and a preparation method thereof, which is used for manufacturing and producing nozzle sealing adhesive parts, comprises the following steps:

[0043] S1: Prepare raw materials, including composite rubber and pre-treated interlayer cloth; the main rubber of the composite rubber is first-class smoked sheet rubber, and its components are 100 parts of first-class smoked sheet rubber, 5 parts of zinc oxide, 1.5 parts of stearic acid, 3 parts of sulfur, 1.2 parts of accelerator DM, 0.7 parts of antioxidant D, 1.5 parts of antioxidant 4010, 20 parts of white carbon black, 1.5 parts of paraffin wax, and 1.7 parts of adhesive A. The above components are all commercially available products. They are mixed to form mixed films. The films should be stacked in layers, and clean cotton cloth should be used to separate adjacent layers. The number of stacked layers should not exceed 4, and ordinary cotton cloth should be used to separate the middle to prevent the films from sticking together during transportation and storage.

[0044] The pre-treated interlayer fabric is coated with adhesive A on the surface of nylon cloth and air-dried. The adhesive is required to be dry and the coating is uniform. It is stored in black plastic bags to avoid direct sunlight. The composite rubber compound is mixed evenly, the pre-treated interlayer fabric adhesive is dry, the coating is uniform, the texture is dense, and there are no defects such as missing adhesive and missing fabric texture.

[0045] S2: Compound rubber is refined into sheets: the sheets are rolled out on the open mill, and each section of the mixed rubber sheet (weight not exceeding 5 kg) is filled with materials and then triangularly packaged, and then thinned out into sheets. The thickness of the sheet is 2.0mm to 2.5mm, and the newly refined rubber sheet should be left for at least 4 hours before being used for vulcanization.

[0046] S3: Composite rubber cutting: First use a circle to plan the line, then cut the shape and weigh it. The film is two identical films with an outer diameter of φ250mm. In addition to cutting the shape, the film also needs to cut 4 notches. The total weight is 300g.

[0047] S4: Pre-treatment of the interlayer cloth and cutting the shape: first use a circle to plan the line, then cut the shape. The outer diameter of the pre-treatment interlayer cloth is φ280mm, and the number of layers is 1.

[0048] S5: Preheating the mold: Check that the mold and vulcanizer are in good condition, and the parallelism of the upper and lower working platforms is not greater than 0.40mm. Place the mold on the heating plate of the vulcanizer for preheating. The preheating temperature is 140℃±5℃. The preheating time is 20min to ensure that the temperature of each part of the mold is uniform.

[0049] S6: Filling: First, put a layer of film weighed into the lower mold cavity, then put a layer of pre-treated cloth on it, and finally put a layer of film on the pre-treated cloth, and fix the pre-treated cloth with the upper mold fixing ring. The center of the rubber and the pre-treated cloth must coincide with the center of the mold.

[0050] S7: Mold closing and heating: Push the mold steadily onto the vulcanizer platform, requiring the mold pressure center to coincide with the vulcanizer pressure center, and heat randomly.

[0051] S8: Pressurization and exhaust: First pressurize to 6MPa, then release the pressure; then pressurize to 8MPa, then release the pressure; pressurize to 10MPa, then release the pressure; finally pressurize to 11MPa and exhaust for no less than 3 times to eliminate the air in the mold cavity. The pressurization and exhaust time shall not exceed 2min.

[0052] S9: Vulcanization: The composite rubber and pre-treated interlayer fabric are vulcanized and molded as a whole. The upper and lower platform temperature of the vulcanizer is 140℃±5℃, the pressure is 11MPa±2MPa, and the temperature and pressure are kept for 30 minutes.

[0053] S10: Opening the mold: When the vulcanization time is reached, the mold is taken out and moved to the working platform, and the mold is opened to take out the vulcanized integrally formed plugging cover 1.

[0054] S11: Cooling: Place the molded plugging and capping product in a clean, flat place to cool naturally to room temperature. During the cooling process of the product, the bottom needs to be compacted with a small pressing block (no more than 3kg) to prevent the bottom from cooling unevenly.

[0055] S12: First gas pressure blasting: Install the vulcanized integrally formed plugging cover on the blasting fixture 2; introduce nitrogen gas to increase the pressure for blasting, the blasting pressure is 1.75MPa, meeting the design index requirements. The plug 3 is made by turning a cloth-reinforced rubber rod, and its outer dimensions match the inner hole dimensions of the plugging cover 1. When in use, screw it into the inner hole of the plugging cover 1 with force to ensure the airtightness of the blasting test.

[0056] Example 2

[0057] The composite rubber and pre-treated cloth are integrally vulcanized and molded to prepare a nozzle low-pressure blasting plugging cover with a specification of height 50mm (height) × φ320mm (outer circle).

[0058] A low-pressure blasting plugging cover for a nozzle and a preparation method thereof, which is used for manufacturing and producing nozzle sealing adhesive parts, comprises the following steps:

[0059] S1: Prepare raw materials, including composite rubber and pre-treated interlayer cloth; the main rubber of the composite rubber is first-class smoked sheet rubber, and its components are 100 parts of first-class smoked sheet rubber, 5 parts of zinc oxide, 1.5 parts of stearic acid, 3 parts of sulfur, 1.2 parts of accelerator DM, 0.7 parts of antioxidant D, 1.5 parts of antioxidant 4010, 20 parts of white carbon black, 1.5 parts of paraffin wax, and 1.7 parts of adhesive A. The above components are all commercially available products. They are mixed to form mixed films. The films should be stacked in layers, and clean cotton cloth should be used to separate adjacent layers. The number of stacked layers should not exceed 4, and cotton cloth should be used to separate the layers in the middle to prevent the films from sticking together during transportation and storage.

[0060] The pre-treated interlayer fabric is coated with adhesive A on the surface of nylon cloth and air-dried. The adhesive is required to be dry and the coating is uniform. It is stored in black plastic bags to avoid direct sunlight. The composite rubber compound is mixed evenly, the pre-treated interlayer fabric adhesive is dry, the coating is uniform, the texture is dense, and there are no defects such as missing adhesive and missing fabric texture.

[0061] S2: Compound rubber is refined into sheets: the sheets are rolled out on the open mill, and each section of the mixed rubber sheet (weight not exceeding 5 kg) is filled with materials and then triangularly packaged, and then thinned out into sheets. The thickness of the sheet is 2.0mm to 2.5mm, and the newly refined rubber sheet should be left for at least 4 hours before being used for vulcanization.

[0062] S3: Composite rubber cutting: First use a circle to plan the line, then cut the shape and weigh it. The film is two identical films with an outer diameter of φ250mm. In addition to cutting the shape, the film also needs to cut 4 notches. The total weight is 320g.

[0063] S4: Pre-treatment of the interlayer cloth, cutting and punching: First, use a compass or template to mark the line, and then cut the shape. The outer diameter of the pre-treatment interlayer cloth is φ290mm, and the number of layers is 1.

[0064] S5: Preheating the mold: Check that the mold and vulcanizer are in good condition, and the parallelism of the upper and lower working platforms is not greater than 0.40mm. Place the mold on the heating plate of the vulcanizer for preheating. The preheating temperature is 140℃±5℃. The preheating time is 20min to ensure that the temperature of each part of the mold is uniform.

[0065] S6: Filling: First, put a layer of film weighed into the lower mold cavity, then put a layer of pre-treated cloth on it, and finally put a layer of film on the pre-treated cloth, and fix the pre-treated cloth with the upper mold fixing ring. The center of the rubber and the pre-treated cloth must coincide with the center of the mold.

[0066] S7: Mold closing and heating: Push the mold steadily onto the vulcanizer platform, requiring the mold pressure center to coincide with the vulcanizer pressure center, and heat randomly.

[0067] S8: Pressurization and exhaust: First pressurize to 6MPa, then release the pressure; then pressurize to 8MPa, then release the pressure; pressurize to 10MPa, then release the pressure; finally pressurize to 11MPa and exhaust for no less than 3 times to eliminate the air in the mold cavity. The pressurization and exhaust time shall not exceed 2min.

[0068] S9: Vulcanization: The composite rubber and pre-treated interlayer fabric are vulcanized and molded as a whole. The upper and lower platform temperature of the vulcanizer is 140℃±5℃, the pressure is 11MPa±2MPa, and the temperature and pressure are maintained for 35 minutes.

[0069] S10: Opening the mold: When the vulcanization time is reached, the mold is taken out and moved to the working platform, and the mold is opened to take out the vulcanized integrally formed plugging cover 1.

[0070] S11: Cooling: Place the molded plugging and capping product in a clean, flat place to cool naturally to room temperature. During the cooling process of the product, the bottom needs to be compacted with a small pressing block (no more than 3kg) to prevent the bottom from cooling unevenly.

[0071] S12: First gas pressure blasting: Install the vulcanized integrally formed plugging cover on the blasting fixture 2; introduce nitrogen gas to increase the pressure for blasting, the blasting pressure is 1.95MPa, meeting the design index requirements. The plug 3 is made by turning a cloth-reinforced rubber rod, and its outer dimensions match the inner hole dimensions of the plugging cover 1. When in use, screw it into the inner hole of the plugging cover 1 with force to ensure the airtightness of the blasting test.

[0072] Example 3

[0073] The composite rubber and pre-treated cloth are integrally vulcanized and molded to prepare a nozzle low-pressure blasting plugging cover with a specification of height 50mm (height) × φ320mm (outer circle).

[0074] A low-pressure blasting plugging cover for a nozzle and a preparation method thereof, which is used for manufacturing and producing nozzle sealing adhesive parts, comprises the following steps:

[0075] S1: Prepare raw materials, including composite rubber and pre-treated interlayer cloth; the main rubber of the composite rubber is first-class smoked sheet rubber, and its components are 100 parts of first-class smoked sheet rubber, 8 parts of zinc oxide, 3 parts of stearic acid, 5 parts of sulfur, 3 parts of accelerator DM, 1.5 parts of antioxidant D, 3 parts of antioxidant 4010, 25 parts of white carbon black, 3 parts of paraffin, and 3 parts of adhesive A. The above components are all commercially available products. They are mixed to form mixed films. The films should be stacked in layers, and clean cotton cloth is used to separate adjacent layers. The number of stacked layers should not exceed 4, and cotton cloth is used to separate the middle, mainly to prevent the films from sticking together during transportation and storage.

[0076] The pre-treated interlayer fabric is coated with adhesive A on the surface of nylon cloth and air-dried. The adhesive is required to be dry and the coating is uniform. It is stored in black plastic bags to avoid direct sunlight. The composite rubber compound is mixed evenly, the pre-treated interlayer fabric adhesive is dry, the coating is uniform, the texture is dense, and there are no defects such as missing adhesive and missing fabric texture.

[0077] S2: Compound rubber is refined into sheets: the sheets are rolled out on the open mill, and each section of the mixed rubber sheet (weight not exceeding 5 kg) is filled with materials and then triangularly packaged, and then thinned out into sheets. The thickness of the sheet is 2.0mm to 2.5mm, and the newly refined rubber sheet should be left for at least 4 hours before being used for vulcanization.

[0078] S3: Composite rubber cutting: First use a compass or a self-made paper template to mark the line, then cut the shape and weigh it. The film is two identical films with an outer diameter of φ255. In addition to cutting the shape, the film also needs to cut 4 notches. The total weight is 310g.

[0079] S4: Pre-treatment of the interlayer cloth, cutting and punching: First, use a compass or template to mark the line, and then cut the shape. The outer diameter of the pre-treatment interlayer cloth is φ285, and the number of layers is 1.

[0080] S5: Preheating the mold: Check that the mold and vulcanizer are in good condition, and the parallelism of the upper and lower working platforms is not greater than 0.40mm. Place the mold on the heating plate of the vulcanizer for preheating. The preheating temperature is 140℃±5℃. The preheating time is 20min to ensure that the temperature of each part of the mold is uniform.

[0081] S6: Filling: First, put a layer of film weighed into the lower mold cavity, then put a layer of pre-treated cloth on it, and finally put a layer of film on the pre-treated cloth, and fix the pre-treated cloth with the upper mold fixing ring. The center of the rubber and the pre-treated cloth must coincide with the center of the mold.

[0082] S7: Mold closing and heating: Push the mold steadily onto the vulcanizer platform, requiring the mold pressure center to coincide with the vulcanizer pressure center, and heat randomly.

[0083] S8: Pressurization and exhaust: First pressurize to 6MPa, then release the pressure; then pressurize to 8MPa, then release the pressure; pressurize to 10MPa, then release the pressure; finally pressurize to 11MPa and exhaust for no less than 3 times to eliminate the air in the mold cavity. The pressurization and exhaust time shall not exceed 2min.

[0084] S9: Vulcanization: The composite rubber and pre-treated interlayer fabric are vulcanized and molded as a whole. The upper and lower platform temperature of the vulcanizer is 140℃±5℃, the pressure is 11MPa±2MPa, and the temperature and pressure are maintained for 32 minutes.

[0085] S10: Opening the mold: When the vulcanization time is reached, the mold is taken out and moved to the working platform, and the mold is opened to take out the vulcanized integrally formed plugging cover 1.

[0086] S11: Cooling: Place the molded plugging and capping product in a clean, flat place to cool naturally to room temperature. During the cooling process of the product, the bottom needs to be compacted with a small pressing block (no more than 3kg) to prevent the bottom from cooling unevenly.

[0087] S12: After the vulcanized integrally formed plug cap is bonded and cured to the nozzle, the airtightness test is qualified, and the pumping pressure is 1.92MPa, which meets the design requirements. The plug 3 is made by turning a cloth-reinforced rubber rod, and its outer dimensions match the inner hole dimensions of the plug cap 1. When in use, it is screwed into the inner hole of the plug cap 1 with force to ensure the airtightness of the bursting test.

[0088] The above are only specific embodiments of the present invention. It should be pointed out that any changes or substitutions that can be easily thought of by any technician familiar with the field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. The rest not described in detail are prior arts.

Claims

1. A method for preparing a low-pressure blasting plugging cap for a nozzle, characterized in that: The steps include: S1: Prepare raw materials: the raw materials include composite rubber and pre-treated interlayer cloth, and the composite rubber is mixed to form a mixed rubber sheet; S2: Compound rubber is refined into sheets: the sheets are rolled out on an open mixing mill, each section of the mixed rubber sheet is filled with materials and then triangularly packaged, and then thinned out to obtain compound rubber sheets; S3: Shearing of composite rubber sheet: Take two layers of composite rubber sheets, mark them, shear them and weigh them to obtain the sheared composite rubber sheets; S4: Pre-treated interlayer fabric cutting: Take a layer of pre-treated interlayer fabric, mark it first and then cut it into shape to obtain the pre-treated interlayer fabric after cutting; S5: Mold preheating: Check the mold and vulcanizer, and place the mold on the vulcanizer heating plate for preheating; S6: Filling: filling the sheared composite rubber sheet and pre-treated sandwich cloth into the mold cavity; S7: Mold closing and heating: Push the mold steadily onto the vulcanizer platform, the pressure center of the mold coincides with the pressure center of the vulcanizer, and the temperature is raised randomly; S8: Pressurization and exhaust: pressurization is carried out in a step-by-step manner, and exhaust is performed at the same time to eliminate the air in the mold cavity; S9: Vulcanization: The composite rubber and pre-treated interlayer fabric are vulcanized and formed into one piece; S10: mold opening: after vulcanization, the mold is taken out and moved to the working platform, and the mold is opened to take out the vulcanized integrally formed plug cover; S11: Cooling: naturally cooling the vulcanized integrally formed plugging and capping product to room temperature after demoulding; S12: First piece gas pressure blasting: The first piece of each batch of plugging cap products is used for gas pressure blasting test. The blasting pressure is between 1.6MPa and 2.0Mpa, and the low-pressure blasting plugging cap for nozzle is obtained.

2. The method for preparing the low-pressure blasting plugging cap for the nozzle according to claim 1, characterized in that: In the step S1, the composite rubber comprises the following components by weight: 100 parts of first-grade smoked sheet rubber, 5-8 parts of zinc oxide, 1.5-3 parts of stearic acid, 3-5 parts of sulfur, 1.2-3 parts of accelerator, 0.7-1.5 parts of antioxidant, 1.5-3 parts of antioxidant, 20-25 parts of white carbon black, 1.5-3 parts of paraffin wax, and 1.7-3 parts of adhesive; The mixed rubber sheets made of the composite rubber are stacked in layers, with cotton cloth placed between two adjacent layers, and the number of stacked layers does not exceed 4; The pre-treated sandwich cloth is made of nylon cloth with adhesive coated on its surface, and after drying, a dry coating is formed on the surface, and the coating is evenly distributed.

3. The method for preparing the low-pressure blasting plugging cap for the nozzle according to claim 1, characterized in that: In the step S2, the weight of each section of the mixed film is ≤5Kg, the thickness of the film after the thin film processing is 2.0mm-2.5mm, and the static time of the film after the film is produced is ≥4h.

4. The method for preparing the low-pressure blasting plugging cap for the nozzle according to claim 1, characterized in that: In step S3, the sheared composite rubber sheet is two identical layers of rubber sheets, with an outer diameter of φ250 mm to φ280 mm, and a plurality of notches are cut on the composite rubber sheet, with a total weight of 300 g to 350 g; In the step S4, the outer diameter of the pre-treated clamping cloth after shearing is φ270 mm to φ290 mm.

5. The method for preparing the low-pressure blasting plugging cap for the nozzle according to claim 1, characterized in that: In step S5, the mold and the vulcanizer are checked to ensure that the parallelism of the upper and lower working platforms is not greater than 0.40 mm; the preheating temperature is 135° C. to 145° C., and the preheating time is 20 min to 40 min.

6. The method for preparing the low-pressure blasting plugging cap for nozzle according to claim 1, characterized in that: In step S6, firstly, a layer of composite rubber sheet is placed in the lower mold cavity, then a layer of pretreated cloth is placed thereon, and finally a layer of composite rubber sheet is placed on the pretreated cloth, the pretreated cloth is fixed with an upper mold fixing ring, and the centers of the composite rubber sheet and the pretreated cloth coincide with the center of the mold.

7. The method for preparing the low-pressure blasting plugging cap for the nozzle according to claim 1, characterized in that: In the step S8, firstly, the pressure is increased to 6MPa-7MPa, and then the pressure is released; then the pressure is increased to 8MPa-9MPa, and then the pressure is released; then the pressure is increased to 10MPa-11MPa, and then the pressure is released; finally, the pressure is increased to 11MPa-12MPa; the number of exhaust times is not less than 3 times, so as to eliminate the air in the mold cavity; the pressurization and exhaust time does not exceed 2min.

8. The method for preparing the low-pressure blasting plugging cap for nozzle according to claim 1, characterized in that: In step S9, the temperature of the upper and lower platforms of the vulcanizer is 135° C. to 145° C., the pressure is 9 MPa to 13 MPa, and the temperature and pressure are maintained for 30 min to 35 min.

9. The method for preparing the low-pressure blasting plugging cap for nozzle according to claim 1, characterized in that: In the step S11, the gas pressure blasting test is specifically to install the vulcanized integrally formed plugging cover on the blasting fixture, introduce nitrogen gas to increase the pressure and blast, and the time from the start of inflation to the blasting is controlled between 1.5min and 2min, and the blasting pressure is between 1.6MPa and 2.0MPa.

10. A low-pressure blasting plugging cap for a nozzle, characterized in that: The low-pressure blasting plugging cover for the nozzle is vulcanized and molded as a whole from composite rubber and pre-treated cloth. The low-pressure blasting plugging cover for the nozzle is prepared by the preparation method of the low-pressure blasting plugging cover for the nozzle according to any one of claims 1 to 9; the low-pressure blasting plugging cover for the nozzle can withstand a pressure of 1.6MPa to 2.0Mpa after being bonded and cured to the nozzle.

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