Process for forming indentations and weakened slots on a reverse dome burst disc

Abstract

The present application relates to the technical field of rupture disc processing, and provides a forming process for indentations and weak grooves on a reverse-arched rupture disc, which can change the overall rigidity of the structure during forming, has high forming efficiency and low waste rate, and comprises the following steps: 1) a material selection and size design step of a flat plate-shaped rupture disc; 2) a forming step of blowing and forming the flat plate-shaped rupture disc into a reverse-arched rupture disc through a blowing and forming die; 3) a processing step of weak grooves on the reverse-arched rupture disc; and 4) a step of installing the reverse-arched rupture disc on a blasting test device to perform a blasting test, wherein the flat plate-shaped rupture disc in the step 2) is blown and formed into a reverse-arched rupture disc through a blowing and forming die, and at least one indentation is formed on the surface of the reverse-arched rupture disc at the same time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rupture disc processing, in particular to a forming process of indentations and weak grooves on a reverse-arched rupture disc. BACKGROUND

[0002] A rupture disc is a pressure relief device that bursts at a set pressure and cannot be reclosed after bursting. When the pressure in the system exceeds the pressure limit of the rupture disc, the rupture disc will burst to release the system pressure and ensure system safety.

[0003] Currently, rupture discs are commonly made of stainless steel material to manufacture flat rupture discs or arched rupture discs, and the arched rupture discs are further divided into positive-arched rupture discs and reverse-arched rupture discs. The positive-arched rupture disc refers to a rupture disc in which a metal sheet is pre-pressed into an arch shape and the arch surface (convex surface) faces the pressure relief side during installation. It is a tensile rupture disc, which is stretched and damaged due to excessive plastic deformation when the pressure exceeds the pressure limit. Some positive-arched rupture discs will have a small amount of debris when they burst. The reverse-arched rupture disc refers to a rupture disc in which a metal sheet is pre-pressed into an arch shape and the arch surface (convex surface) faces the pressure side during installation. It is a compression rupture disc, which is deformed by flipping due to instability when the pressure exceeds the pressure limit. It can form a relief port in multiple ways, and almost no debris is generated when it bursts. Moreover, the burst pressure of the reverse-arched rupture disc is lower under the same thickness, and thus it is more widely used.

[0004] In the prior art, in order to meet the design requirements of the burst pressure, the method of changing the thickness of the material is commonly used. However, when designing a rupture disc with a lower burst pressure, the method of changing the thickness of the material alone is difficult or even impossible to process due to the selection of a thinner material thickness. In order to further reduce the burst pressure of the reverse-arched rupture disc without changing the thickness of the material, a method has been developed in China to set indentations on the reverse-arched rupture disc to change the overall structural rigidity of the reverse-arched rupture disc and cause the arch shape to flip due to plastic deformation of the indentations to further reduce the burst pressure. The relief mode of the weak groove relief port on the reverse-arched rupture disc ensures that it bursts at the designed burst pressure and during the process of flipping instability. The internal pressure of the system when the plastic deformation of the indentation occurs is the arch instability pressure of the reverse-arched rupture disc. However, the current manufacturing process of the indentation is mainly to form a reverse arch on the flat rupture disc and then manufacture the indentation on the rupture disc. However, this method changes the local rigidity of the reverse-arched rupture disc after forming and causes severe local stress concentration, which makes it difficult to accurately control the burst pressure of the entire reverse-arched rupture disc. The manufacturing of the weak groove is mainly by cold extrusion and slotting. During the processing, the structure of the root of the weak groove will crack and stress concentration will occur due to extrusion processing. At the same time, the brittleness of the stainless steel material will increase due to cold work hardening during extrusion processing, which makes it more difficult to control the burst pressure of the entire reverse-arched rupture disc. SUMMARY

[0005] In order to solve the above problems, the present application provides a process for forming a pressure mark and a weak groove on an inverse-arched bursting disc, which can change the overall rigidity of the structure during forming, has high forming efficiency and low waste rate.

[0006] To achieve the above object, the present application discloses a process for forming a pressure mark and a weak groove on an inverse-arched bursting disc, which comprises the following steps: 1) material selection and size design of a flat-arched bursting disc; 2) forming of the flat-arched bursting disc by blowing and forming a mold; 3) processing of the weak groove on the inverse-arched bursting disc; and 4) installation of the inverse-arched bursting disc on a test equipment for explosion test. In the step 2), the flat-arched bursting disc is blown and formed into an inverse-arched bursting disc by a blowing and forming mold, and at least one pressure mark is formed on the surface of the inverse-arched bursting disc.

[0007] Further improvement is that the blowing and forming mold comprises a lower forming tool, an upper forming tool and a pressure mark forming cutter. The lower forming tool is provided with a first through hole for air inlet in the middle part, and the upper part of the lower forming tool is provided with a positioning groove. The flat-arched bursting disc is placed on the bottom surface of the positioning groove of the lower forming tool during blowing, and the flat-arched bursting disc completely covers the first through hole. The upper forming tool is provided with a second through hole for air outlet in the middle part. The lower part of the outer end surface of the upper forming tool is connected with the positioning groove, and the lower part of the bottom surface of the upper forming tool is connected with the flat-arched bursting disc. The pressure mark forming cutter is provided with a third through hole in the middle part, which is communicated with the second through hole. The pressure mark forming cutter comprises a support provided on the upper end of the upper forming tool and a forming blade provided on the lower part of the support. When the middle part of the flat-arched bursting disc is blown and formed into an inverse-arched shape, the bottom end of the blade is used to abut against the inverse-arched bursting disc to promote the forming of the pressure mark. The outer end surface of the forming blade is connected with the second through hole. The first through hole is inflated and pressurized until the flat-arched bursting disc is blown and formed into the inverse-arched bursting disc with a designed height of arch, and the forming of the pressure mark on the inverse-arched bursting disc is promoted.

[0008] Further improvement is that the blowing and forming mold further comprises an adjusting gasket provided on the upper end surface of the upper forming tool for adjusting the position of the forming blade.

[0009] Further improvement is that the material of the flat-arched bursting disc is selected from stainless steel.

[0010] Further improvement is that the step 2) needs to use a clamping device to clamp the blowing and forming mold during the blowing and forming process of the flat-arched bursting disc.

[0011] Further improvement is that the laser processing equipment is used for processing the weak groove in step 3), and the laser processing power is in the range of 30W-50W.

[0012] Further improvement is that the first aging treatment and the second aging treatment are needed after the forming processing of step 2) and step 3).

[0013] Further improvement is that the first aging treatment and the second aging treatment are both in the form of natural aging treatment, and the aging time is more than 4h.

[0014] After the above technical scheme is used, the application has the following beneficial effects:

[0015] 1. The indentation and the arch of the reverse-arched bursting disc are formed at the same time, the overall structural rigidity of the reverse-arched bursting disc is changed in the forming process, the local rigidity change and the local stress concentration phenomenon are avoided, the uncertain influencing factors of the bursting pressure of the reverse-arched bursting disc are increased, the bursting pressure is more difficult to control, and the forming efficiency of the reverse-arched bursting disc is improved.

[0016] 2. The indentation of the reverse-arched bursting disc does not need to be processed twice, the reverse-arched bursting disc is not damaged twice, the influence of the second indentation forming on the overall performance index of the reverse-arched bursting disc is reduced, and the waste rate of the reverse-arched bursting disc during forming is further reduced.

[0017] 3. The weak groove structure is processed by laser processing equipment, which not only improves the processing precision of the weak groove, but also avoids the crack and stress concentration phenomenon of the root structure of the weak groove caused by extrusion processing, and avoids the cold work hardening of stainless steel material caused by extrusion processing, prevents the increase of brittleness of stainless steel material, and effectively prevents the complexity of the influencing factors of the reverse-arched bursting disc during blasting. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical scheme in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0019] Figure 1 is a top view of the reverse-arched bursting disc of the application.

[0020] Figure 2 is a front view of the reverse-arched bursting disc of the application.

[0021] Figure 3 is a sectional view of the blow molding die of the present application.

[0022] Figure 4 is a structural schematic diagram of the reverse-arched bursting disc after blow molding.

[0023] Figure 5 is a processing process demonstration diagram of the upper weak groove of the reverse-arched bursting disc of the present application.

[0024] Figure 6 is a structural schematic diagram of the lower forming tool of the present application.

[0025] Figure 7 is a structural schematic diagram of the upper forming tool of the present application.

[0026] Figure 8 is a structural schematic diagram of the indentation forming tool of the present application.

[0027] Figure 9 is a structural schematic diagram of other structural forms of the indentation forming tool of the present application.

[0028] Figure 10 is an enlarged schematic diagram of the indentation of the present application.

[0029] Figure 11 is an enlarged schematic diagram of the weak groove of the present application. Embodiment

[0030] The present application will be further described in conjunction with the drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0031] Reference Figures 1 to 11 The technical solution adopted in the present embodiment is as follows:

[0032] An indentation and weak groove forming process of a reverse-arched bursting disc, comprising: 1) a material selection and size design step of a flat plate-shaped bursting disc 5; 2) a forming step of blowing the flat plate-shaped bursting disc 5 through a blow molding die 4 into a reverse-arched bursting disc 1; 3) a processing step of a weak groove 3 on the reverse-arched bursting disc 1; 4) a step of installing the reverse-arched bursting disc 1 on a blasting tool device for blasting test, wherein the flat plate-shaped bursting disc 5 in the step 2) is blown through the blow molding die 4 into the reverse-arched bursting disc 1, and at least one indentation 2 is formed on the surface of the reverse-arched bursting disc 1. In the present embodiment, the number of the indentation 2 is one.

[0033] The indentation 2 can make the reverse-arched rupture disc 1 unstable and flip over at the designed burst pressure, and the weak groove 3 can make the reverse-arched rupture disc 1 crack at the weak groove 3 during the flipping of the arch, thus assisting the reverse-arched rupture disc 1 to burst from the weak groove 3 at the designed burst pressure, and the design of the weak groove 3 can also help to ensure the burst opening area of the reverse-arched rupture disc 1.

[0034] The blow forming die 4 comprises a forming lower tool 41, a forming upper tool 42 and an indentation forming cutter 43. The forming lower tool 41 is provided with a first through hole 51 in the middle for air inlet, and the upper part of the forming lower tool 41 is provided with a positioning groove 6 for mating connection with the flat plate-shaped rupture disc 5 to accommodate and position the flat plate-shaped rupture disc 5. The middle part of the forming upper tool 42 is provided with a second through hole 52 for air outlet, and the first through hole 51 and the second through hole 52 are in communication when the flat plate-shaped rupture disc 5 is not installed. During blow forming, the flat plate-shaped rupture disc 5 is placed on the bottom surface of the positioning groove 6 of the forming lower tool 41 and covers the first through hole 51 completely, the lower outer end surface 421 of the forming upper tool 42 is connected with the positioning groove 6, and the lower bottom surface of the forming upper tool 42 is connected with the flat plate-shaped rupture disc 5. The middle part of the indentation forming cutter 43 is provided with a third through hole 53 in communication with the second through hole 52. The indentation forming cutter 43 comprises a support 431 provided on the upper end of the forming upper tool 42 and a forming blade 432 provided on the lower part of the support 431 and used for abutting against the reverse-arched rupture disc 1 to promote the forming of the indentation 2 when the middle part of the flat plate-shaped rupture disc 5 is blown into an arch. The outer end surface 4321 of the forming blade 432 is connected with the second through hole 52. The forming blade 432 is shaped as the shape left after the lower left part of a ring-shaped column is cut obliquely. The bottom edge 4322 of the forming blade 432 is processed according to the design shape of the indentation, as shown in the figure. Figure 8 During blow forming, the first through hole 51 is inflated and pressurized until the flat plate-shaped rupture disc 5 is blown into the reverse-arched rupture disc 1 with an arch satisfying the design height requirement due to the pressure, and the forming of the indentation 2 on the reverse-arched rupture disc 1 is promoted.

[0035] The blow forming die 4 further comprises an adjusting gasket 7 provided on the upper end surface of the forming upper tool 42 for adjusting the position of the bottom edge 4322 of the forming blade 432.

[0036] The material of the flat plate-shaped rupture disc 5 is selected from stainless steel.

[0037] During the blow forming process of the flat plate-shaped rupture disc 5, a clamping device is used to clamp the blow forming die 4.

[0038] The processing of the weakened groove 3 in step 3) uses a laser processing device, and the laser processing power is in the range of 30W-50W.

[0039] After the forming process of steps 2) and 3), the anti-arch rupture disc 1 needs to be subjected to first aging treatment and second aging treatment, respectively.

[0040] Both the first aging treatment and the second aging treatment use natural aging treatment, and each aging time is more than 4h.

[0041] The specific process includes the following steps:

[0042] Step 1: The material of the flat plate-shaped rupture disc 5 is stainless steel material, and in this embodiment, 316L stainless steel material is selected. The structure of the anti-arch rupture disc 1 that meets the burst pressure value and the size specification of the flat plate-shaped rupture disc 5 required for forming the anti-arch rupture disc 1 are designed by combining computer design software and simulation software.

[0043] Step 2: Place the flat plate-shaped rupture disc 5 on the bottom surface of the positioning groove 6 of the lower forming tool 41, and make the flat plate-shaped rupture disc 5 completely cover the first through hole 51. Then, connect the upper forming tool 42 with the lower forming tool 41 through the positioning groove 6, and accommodate and position the flat plate-shaped rupture disc 5 between the lower forming tool 41 and the upper forming tool 42. Place the adjusting gasket 7 on the upper end surface of the upper forming tool 42, and finally place the support 431 of the indentation forming cutter 43 on the upper end surface of the adjusting gasket 7, and complete the positioning and installation of the indentation forming cutter 43 by connecting the outer end surface 4321 of the forming blade 432 with the second through hole 52. The initial thickness of the adjusting gasket 7 is primarily to ensure that the bottom blade edge 4322 of the forming blade 432 does not interfere with the upper end surface of the flat plate-shaped rupture disc 5 during initial installation.

[0044] Step 3: Install the blow forming mold 4 on the clamping device. The lower end surface of the lower forming tool 41 is fixed on the installation platform 8 of the clamping device, and the upper end surface is first pre-pressed and then slowly pressed with a small pressure increase rate by the clamping device, and finally the blow forming mold 4 is ensured to be in a clamped state, as shown in Figure 3 In this embodiment, the clamping device uses a hydraulic machine.

[0045] Step 4: inflate and pressurize the first through hole 51 of the forming lower tooling 41 until the flat plate shaped bursting disc 5 is inflated to the inverse arch shaped bursting disc 1 with arch height meeting the design requirement and at the same time promote the forming of the pressure mark 2 on the inverse arch shaped bursting disc 1, at this time maintain the current pressure for 10-15s and then slowly release the pressure, as shown in Figure 4 .

[0046] Step 5: after the pressure release is completed, loosen the clamping force of the clamping device, take off the inverse arch shaped bursting disc 1 from the inflation forming die 4 and perform the first natural aging treatment, the aging treatment time is more than 4h.

[0047] Step 6: install the formed inverse arch shaped bursting disc 1 on the laser processing platform 9 through the three positioning mounting holes 11 provided on the inverse arch shaped bursting disc 1, adjust the laser processing power, and heat melt the flat part of the inverse arch shaped bursting disc 1 through the program control of the laser beam head 10 to process the arc segment semicircular weak groove 3 with a certain depth, as shown in Figure 5 . The value of the laser processing power is in the range of 30W-50W, and the depth of the weak groove 3 is generally processed to about 1 / 3 of the thickness of the entire inverse arch shaped bursting disc 1, if the test opening effect is not good, a little more depth is processed until the inverse arch shaped bursting disc 1 can be burst along the arc segment of the weak groove 3 during the arch instability overturning process.

[0048] Step 7: take out the inverse arch shaped bursting disc 1 and perform the second natural aging treatment again, the aging treatment time is also more than 4h.

[0049] Step 8: install the inverse arch shaped bursting disc 1 after aging treatment on the burst testing tooling equipment to perform burst testing and obtain the actual burst pressure value of the formed inverse arch shaped bursting disc 1.

[0050] Step 9: if the actual burst pressure value meets the design requirement, record the pressurization pressure of the clamping device at this time, the inflation pressure of the dome forming, and the thickness of the gasket 7, and the subsequent batch forming is performed according to the recorded parameters; if the actual burst pressure value does not meet the design requirement, adjust the thickness of the gasket 7 to change the position and shape of the pressure mark 2 and adjust the processing depth of the weak groove 3, and perform again from step 2 to step 7 until the burst pressure is qualified.

[0051] The thickness adjustment of the gasket 7 will affect the distance between the bottom blade edge 4322 of the forming blade 432 and the upper end surface of the flat plate shaped bursting disc 5, which is beneficial to adjust and change the longitudinal position and shape of the pressure mark 2 under the same arch height design, and the change of the shape and position of the pressure mark 2 is also beneficial to finely adjust the burst pressure value of the inverse arch shaped bursting disc 1.

[0052] The indentation 2 is formed in the process of forming the vault of the reverse-arched bursting disc 1, that is, in the process of forming the overall structure of the reverse-arched bursting disc 1 which is still in the process of changing and has not yet been shaped. In the forming process, the structural rigidity of the entire reverse-arched bursting disc 1 is changed, so as to avoid the increase of uncertain factors of the bursting pressure of the reverse-arched bursting disc 1 due to the change of local rigidity and the local stress concentration phenomenon, and to make the bursting pressure of the reverse-arched bursting disc 1 more difficult to control.

[0053] The structure of the weak groove 3 is processed by laser processing equipment, which not only improves the processing precision of the weak groove 3, but also avoids the crack and stress concentration phenomenon at the root structure of the weak groove 3 due to extrusion processing, and also avoids the cold work hardening of the stainless steel material due to extrusion processing, so as to prevent the increase of brittleness of the stainless steel material, effectively prevent the complication of the influencing factors of the reverse-arched bursting disc 1 during the explosion, and the corresponding change of the processing depth of the weak groove 3 helps to ensure that the weak groove 3 can be exploded due to the crack caused by deformation during the arch instability overturning of the reverse-arched bursting disc 1.

[0054] It should be noted that the processing depth of the weak groove 7 should meet the condition that the reverse-arched bursting disc 1 is in an unexploded state without the indentation 2 and when the internal pressure of the system reaches the arch instability pressure with the indentation 2, but the auxiliary crack at the weak groove 3 can meet the explosion requirement under the arch instability overturning action with the indentation 2, so the arch instability pressure can be regarded as the bursting pressure of the present application. Obviously, at this time, the arch instability pressure is actually less than the bursting pressure of the arch material itself, which is convenient for the application of the present application in places with lower bursting pressure. The processing position of the weak groove 3 is on the plane part of the reverse-arched bursting disc 1 and is 2-5 mm away from the outer radius of the arch root.

[0055] Based on the technical solutions of the above embodiments, the indentation forming tool 43 can also be designed as Figure 9 The outer end face 4331 of the positioning table 433 is connected with the positioning groove 6 of the forming lower tool 41, and the use of the indentation forming tool 43 with various structural forms will be conducive to adjusting and changing the transverse position and shape of the indentation 2 under the same arch design height.

[0056] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A process for forming indentations and a weakened groove on a reverse dome burst disc, comprising: 1) material selection and size design steps of the flat plate burst disc; 2) forming steps of the flat plate burst disc into the reverse arch burst disc through the blow forming die; 3) processing steps of the weak groove on the reverse arch burst disc; 4) steps of installing the reverse arch burst disc on the explosion test device for explosion test, characterized in that: the flat plate burst disc in the step 2) is formed into the reverse arch burst disc through the blow forming die at the same time at least one indentation is formed on the surface of the reverse arch burst disc; The blow forming die comprises a forming lower tool, a forming upper tool and an indentation forming cutter, the middle part of the forming lower tool is provided with a first through hole for air inlet, the upper part of the forming lower tool is provided with a positioning groove, the flat plate burst disc is placed on the bottom surface of the positioning groove of the forming lower tool during blow forming and the flat plate burst disc completely covers the first through hole, the middle part of the forming upper tool is provided with a second through hole for air outlet, the lower outer end surface of the forming upper tool is connected with the positioning groove and the lower bottom surface of the forming upper tool is connected with the flat plate burst disc, the middle part of the indentation forming cutter is provided with a third through hole which is communicated with the second through hole, the indentation forming cutter comprises a support which is arranged on the upper end of the forming upper tool and a forming blade which is arranged on the lower part of the support and is used for abutting against the reverse arch burst disc to promote the indentation forming when the middle part of the flat plate burst disc is blown into the reverse arch shape, the outer end surface of the forming blade is connected with the second through hole, air is filled into the first through hole during blow forming until the flat plate burst disc is blown into the reverse arch burst disc with the arch shape which meets the design height requirement due to the pressure effect and at the same time the indentation forming on the reverse arch burst disc is promoted.

2. The process for forming indentation and weakening groove on the reverse dome burst disc as claimed in claim 1 wherein: The blow forming die further comprises an adjusting gasket which is arranged on the upper end surface of the forming upper tool and is used for adjusting the position of the forming blade.

3. The process for forming indentation and weakening groove on the reverse dome burst disc as claimed in claim 1 wherein: The material of the flat plate burst disc is stainless steel.

4. The process for forming indentation and weakening groove on reverse dome burst disc as claimed in claim 1 wherein: The step 2) needs to use a clamping device to clamp the blow forming die during the blow forming process of the flat plate burst disc.

5. The process for forming indentation and weakening groove on reverse dome burst disc as claimed in claim 1 wherein: The laser processing equipment is used to process the weak groove in the step 3), the power value of the laser processing equipment is in the range of 30W-50W.

6. The process for forming score and weakening groove on the reverse dome burst disc as claimed in claim 1 wherein: The reverse arch burst disc needs to be subjected to the first aging treatment after the forming process of the step 2) is completed, the reverse arch burst disc needs to be subjected to the second aging treatment after the forming process of the step 3) is completed.

7. The process for forming score and weakening groove on the reverse dome burst disc as claimed in claim 6 wherein: The first aging treatment and the second aging treatment are both natural aging treatment and the aging time of each time is more than 4h.

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