A stop valve bonnet machining process

Abstract

The present application relates to valve cover processing technical field, more specifically, it relates to a kind of stop valve cover processing technology, adopt 304 stainless steel material production valve cover, improve the sanitary performance of product, solve the risk of original brass structure lead separation, simultaneously, without like 201 stainless steel, carry out nickel plating when processing, simplify production step, also reduce production pollution;And in combination with the characteristics of 304 stainless steel material, wire rod is cold upset by cold upsetting process, and valve cover blank is obtained, the processing step is saved, and then the first processing equipment and the second processing equipment are selected according to the processing process, the processing time gap of two equipment is balanced, the equipment waiting time is reduced, the production efficiency is improved, and then the production cost is fully reduced, the valve cover material is upgraded and replaced at low cost, to meet market demand.

Description

Technical Field

[0001] This invention relates to the field of valve cover processing technology, and more specifically, to a valve cover processing technology for a gate valve. Background Technology

[0002] PPR gate valves mainly consist of a PPR valve body, inserts, valve cover, valve core, and lead screw. Currently, the valve covers used in PPR gate valves are all made using a brass hot forging process. Hot forging, also known as hot extrusion, is a hot extrusion process for metal materials. During production, the theoretically required material volume is first calculated, and then the diameter and length of the copper rod are determined. The required length of the copper rod is cut using a cutting machine, and then the copper rod is heated to approximately 760 degrees Celsius and placed into a stamping die for forming (the die needs to be preheated to 200-300 degrees Celsius). Hot forging easily generates work hardening and internal stress, requiring annealing to eliminate stress and optimize the microstructure. Next, the holes, outer diameter, end faces, and threads are machined. Finally, the surface is nickel-plated. Gate valve covers made using this process are expensive, prone to cracking during manufacturing, posing a risk of leakage later, and also carry the risk of lead leaching.

[0003] To reduce material costs, some manufacturers use 201 stainless steel instead of brass for valve covers. However, machining 201 stainless steel using the same processes is 2-3 times more expensive than machining brass. To compensate for this increased cost, manufacturers continuously optimize the structure and reduce material usage. However, this reduction in material usage is easily noticeable in the appearance, leading to low customer acceptance in the market. This is because, with a basically unchanged price, the product is lighter and smaller. Furthermore, 201 stainless steel has relatively poor performance, is prone to rust, and requires nickel plating. Therefore, using 201 stainless steel for valve covers only solves the risk of lead leaching associated with the original brass structure; it doesn't reduce costs, and customer acceptance remains low.

[0004] Therefore, how to solve the problems of high cost and lead leaching risk of copper valve covers, and complex manufacturing process and high machining cost of 201 stainless steel gate valve covers, has become an important research topic in the field of PPR gate valves. Summary of the Invention

[0005] To overcome the defects in the use and production of gate valve covers in the prior art, this invention provides a gate valve cover processing technology that uses higher-performance materials and optimizes the processing technology to reduce production costs and meet market demands.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a valve cover processing technology for a gate valve, comprising the following steps: Step 1: Select 304 stainless steel wire for production. Use cold heading process to head the 304 stainless steel wire into the required valve cover blank. During the process, the clamping reference outer circle is extruded at the first end of the valve cover blank. Step 2: Grind and clean the valve cover blank to remove surface oxide scale and dirt; Step 3: Based on the valve cover processing dimensions and time, select the first processing equipment and the second processing equipment to process both ends of the valve cover blank respectively, so that the processing time difference between the first processing equipment and the second processing equipment is less than 3 seconds; Step 4: Use the first processing equipment to clamp the clamping reference outer circle of the valve cover blank, process the second end of the valve cover blank, and directly process the second end to the required size of the finished product. Then use the second processing equipment to clamp the second end of the processed valve cover blank, process the first end of the valve cover blank, and directly process the first end to the required size of the finished product to obtain the finished valve cover. Step 5: Clean the finished valve cover and put it into storage to complete the production process.

[0007] In step one, the valve cover blank is produced by cold heading process, which saves machining steps; in step two, the valve cover blank is ground and cleaned to prevent oxide scale or other impurities from adhering to the outer circle of the clamping reference, thus ensuring the clamping and machining accuracy of the first processing equipment.

[0008] Preferably, in step one, 304 stainless steel wire of appropriate diameter is selected according to the size of the valve cover. The 304 stainless steel wire is heated to 500-800℃ by a high-frequency heater and then sent to a multi-station cold heading forming machine. The multi-station cold heading forming machine cuts, shapes, stretches, extrudes and punches the wire to produce the valve cover blank.

[0009] Preferably, in step one, during cold heading, all non-rotating surface structures except for threads are cold-headed.

[0010] Preferably, in step one, the cold heading process consists of six steps: the first step is to form a stepped circle, shaping the uneven blank into a stepped circle; the second step is to press the blank into shape by forward extrusion, obtaining a further stepped circle, and leaving a positioning hole at the center of the end face of the first end of the blank to facilitate the guidance of the mold in the next station; the third step is to form an inner hexagon and an outer hexagon by compound extrusion; the fourth step is to continue extrusion to obtain the inner hexagon and the outer clamping reference outer circle; the fifth step is to perform reverse extrusion to obtain the inner stepped process hole; the sixth step is to punch out the central through hole, finally obtaining the required stop valve cover blank.

[0011] Based on the characteristics of 304 stainless steel, the extrusion dimensions for each step are determined to avoid over-extrusion. At the same time, positioning holes are reserved before the internal extrusion hole to improve the internal extrusion accuracy.

[0012] Preferably, in step two, a three-dimensional vibratory grinding machine is used to thoroughly grind the valve cover blank to remove oxide scale and dirt from the surface of the blank.

[0013] Preferably, in step three, the first processing equipment is a dual-spindle CNC lathe, and the second processing equipment is a multi-station combination CNC lathe.

[0014] Both twin-spindle CNC lathes and multi-station combination CNC lathes are existing machining equipment. Twin-spindle CNC lathes have two machining spindles that can process and produce two workpieces at the same time. Multi-station combination CNC lathes have multiple machining stations that process multiple workpieces sequentially, thus shortening the processing time.

[0015] Preferably, the first processing equipment has two processing spindles working simultaneously to process the stepped circle and the flange bevel in sequence.

[0016] Preferably, the second processing equipment operates at multiple stations simultaneously, sequentially processing the outer circle, outer groove, inner hole, inner hole chamfer, and external thread of the first end.

[0017] Preferably, in step four, the valve cover blank processed by the first processing equipment is automatically transported to the elevator of the second processing equipment by a conveyor belt. The first processing equipment uses a feeding vibratory plate for feeding, and the second processing equipment uses a combination of a stepped pusher and a robot for feeding.

[0018] Vibratory feeders and stepped pushers are both commonly used feeding equipment. Depending on the shape of the workpiece, baffles or bars need to be set on the vibratory feeder and stepped pusher to ensure that the workpiece can be fed neatly according to the set arrangement.

[0019] Preferably, in step five, an ultrasonic cleaner is used to clean the finished valve cover.

[0020] Compared with the prior art, the beneficial effects of the present invention are: Using 304 stainless steel to produce valve covers improves the product's hygiene performance, eliminates the risk of lead leaching from the original brass structure, and simplifies the production process by eliminating the need for nickel plating like with 201 stainless steel, thus reducing production pollution. Furthermore, leveraging the characteristics of 304 stainless steel, cold heading is used to cold-forge the wire into valve cover blanks, saving processing steps. By selecting a primary and a secondary processing equipment, the processing time difference between the two is balanced, reducing equipment waiting time, improving production efficiency, and ultimately significantly reducing production costs. This allows for a cost-effective upgrade and replacement of the valve cover material to meet market demands. Attached Figure Description

[0021] Figure 1This is a process flow diagram of a gate valve cover processing technology according to the present invention; Figure 2 This is a schematic diagram of the valve cover processing process of a gate valve according to the present invention; Figure 3 This is a schematic diagram of the clamping device for the first processing equipment in the valve cover processing technology of the gate valve of the present invention; Figure 4 This is a schematic diagram of the clamping of the second processing equipment in a gate valve cover processing process according to the present invention; Figure 5 This is a schematic diagram of the structure of a finished valve cover according to a valve cover processing technology of a stop valve of the present invention; Figure 6 This is a schematic diagram of the cold heading process for processing a gate valve cover according to the present invention.

[0022] In the figure: 1. Valve cover blank; 2. Clamping reference circle; 3. Finished valve cover; 4. First processing equipment chuck; 5. Second processing equipment chuck. Detailed Implementation

[0023] The accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0024] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "long," and "short" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0025] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings: Example 1 like Figure 1-2 As shown, a valve cover processing technology for a gate valve includes the following steps: Step 1: Select 304 stainless steel wire for production. Use cold heading process to head the 304 stainless steel wire into the required valve cover blank 1. During the process, the clamping reference outer circle is extruded at the first end of the valve cover blank 1. Step 2: Grind and clean the valve cover blank 1 to remove surface oxide scale and dirt; Step 3: Based on the valve cover processing dimensions and time, select the first processing equipment and the second processing equipment to process both ends of the valve cover blank 1 respectively, so that the processing time difference between the first processing equipment and the second processing equipment is less than 3 seconds; Step 4: Use the first processing equipment to clamp the clamping reference outer circle of the valve cover blank 1, process the second end of the valve cover blank 1, and process the second end directly to the required size of the finished product. Then use the second processing equipment to clamp the second end of the processed valve cover blank 1, process the first end of the valve cover blank 1, and process the first end directly to the required size of the finished product to obtain the finished valve cover 3. Step 5: Clean the finished valve cover 3 and put it into storage to complete the production.

[0026] In step one, cold heading is used to produce valve cover blank 1, saving machining steps; in step two, valve cover blank 1 is ground and cleaned to prevent oxide scale or other impurities from adhering to the outer circle of the clamping reference, ensuring the clamping and machining accuracy of the first processing equipment. Figure 3 As shown, the first processing equipment chuck 4 holds the valve cover blank 1 in the clamping reference circle 2 for processing; as Figure 4 As shown, the chuck 5 of the second processing equipment holds the second end of the already processed valve cover blank 1 for processing.

[0027] The beneficial effects of this embodiment are as follows: Using 304 stainless steel to produce the valve cover improves the product's hygiene performance, eliminates the risk of lead leaching from the original brass structure, and simplifies the production process by eliminating the need for nickel plating as required for 201 stainless steel, thus reducing production pollution. Furthermore, taking advantage of the characteristics of 304 stainless steel, cold heading is used to cold-head the wire to obtain the valve cover blank 1, saving processing steps. By selecting the first and second processing equipment in conjunction with the processing technology, the difference in processing time between the two equipment is balanced, reducing equipment waiting time, improving production efficiency, and thus significantly reducing production costs. This allows for the upgrade and replacement of the valve cover material at a lower cost, meeting market demands.

[0028] Example 2 This embodiment further defines the features of Embodiment 1, and its difference from Embodiment 1 lies in: like Figure 6As shown, in step one, 304 stainless steel wire of appropriate diameter is selected according to the valve cover size. The 304 stainless steel wire is heated to 500-800℃ by a high-frequency heater and then fed into a multi-station cold heading machine. The multi-station cold heading machine cuts, shapes, stretches, extrudes and punches the wire to produce valve cover blank 1. During cold heading, all non-rotating surface structures except for threads are cold-headed. The cold heading process is divided into six steps: the first step is to form a stepped circle, shaping the uneven blank into a stepped circle; the second step is to press the blank to form a further stepped circle, leaving a positioning hole at the center of the end face of the first end of the blank to facilitate the guidance of the mold in the next station; the third step is to form an inner hexagon and an outer hexagon by compound extrusion; the fourth step is to continue extrusion to obtain the inner hexagon and the outer clamping reference outer circle; the fifth step is to perform reverse extrusion to obtain the inner stepped process hole; the sixth step is to punch out the central through hole, finally obtaining the required stop valve cover blank 1.

[0029] Based on the properties of 304 stainless steel, the extrusion dimensions for each step are determined to avoid over-extrusion. Simultaneously, positioning holes are pre-drilled before the internal extrusion holes to improve internal extrusion precision. Multi-station forming ensures more uniform metal flow at each step, reducing internal stress and thus improving mechanical properties.

[0030] Furthermore, in step two, a three-dimensional vibratory grinding machine is used to thoroughly grind the valve cover blank 1 to remove oxide scale and dirt from the surface of the blank.

[0031] Furthermore, in step three, the first machining equipment is a twin-spindle CNC lathe, and the second machining equipment is a multi-station combination CNC lathe. The two machining spindles of the first machining equipment work simultaneously to machine the stepped circle and the flange bevel sequentially. The multiple stations of the second machining equipment work simultaneously to sequentially machine the outer circle, outer groove, inner hole, inner hole chamfer, and external thread of the first end.

[0032] Both twin-spindle CNC lathes and multi-station combination CNC lathes are existing machining equipment. Twin-spindle CNC lathes have two machining spindles that can process and produce two workpieces at the same time. Multi-station combination CNC lathes have multiple machining stations that process multiple workpieces sequentially, thus shortening the processing time.

[0033] Furthermore, in step four, the valve cover blank 1 processed by the first processing equipment is automatically transported to the elevator of the second processing equipment by a conveyor belt. The first processing equipment uses a feeding vibratory plate for feeding, and the second processing equipment uses a combination of a stepped pusher and a robot for feeding.

[0034] Vibratory feeders and stepped pushers are both commonly used feeding equipment. Depending on the shape of the workpiece, baffles or bars may be set on the vibratory feeder and stepped pusher to ensure that the workpiece is fed neatly according to the set arrangement.

[0035] Furthermore, in step five, an ultrasonic cleaner is used to clean the finished valve cover 3.

[0036] The remaining features and working principles of this embodiment are the same as those of Embodiment 1.

[0037] Example 3 Example of cold heading process for gate valve cover: like Figure 6 As shown, the first step is to form stepped circles (1D), shaping the uneven blank into stepped circles of φ24.7 and φ20.1; the second step is to use a pressing plate (2D), which moves the blank in 1D and then extrudes it to obtain stepped circles of φ40.35 (derived from the φ24.7 pressing plate) and φ20.25, leaving a positioning hole at the center of the φ40.35 end face for guiding the mold in the next station; the third step is to pre-form the internal and external hexagonal parts (3D), moving the blank in 2D to this station for compound extrusion to obtain internal hexagonal S16 and external hexagonal S20.4; the fourth step is to... The process continues by stretching the inner hexagon to essentially shape the outer side (4D). The blank from 3D is then transferred to this station for extrusion to obtain the inner hexagon S15.8 and the outer circle φ15.9, while also obtaining the outer circle φ40.65, which is the clamping reference outer circle. The fifth step involves stretching the inner φ9 hole (5D). The blank from 4D is transferred to this station for reverse extrusion to obtain the inner φ9 stepped hole, while also obtaining the outer circle φ16. The sixth step is final shaping and punching (6D). The blank from 5D is transferred to this station to punch out the φ9 through hole, ultimately obtaining the required gate valve cover blank 1. The resulting gate valve cover blank has high strength and is lighter than the copper gate valve cover blank of the same specification, resulting in high production efficiency and low cost. The cold heading process equipment technology is mature, and the above processing technology can produce one valve cover blank 1 per second, enabling large-scale, high-efficiency material preparation.

[0038] Among them, the internal hexagon S15.8 is located at the bottom of the internal hexagon S16 and is set with stepped extrusion to improve the working life of cold heading dies. In actual use, internal hexagon S15.8 is used as the reference for cooperation. This internal hexagon is used to limit the valve core, so that the valve core moves up and down without rotating. When used, it can be matched with external hexagonal valve cores from S15 to S15.6.

[0039] Example 4 Example of valve cover machining process for gate valve: As shown in Table 1, the first processing equipment uses a dual-spindle CNC lathe, and the second processing equipment uses a multi-station combination CNC lathe. Process 1 is the processing step of the first processing equipment, with a total processing time of 26 seconds. Both spindles process simultaneously, with an average processing time of 13 seconds per piece. Process 2 is the processing step of the second processing equipment, where each axis at each station processes independently without interference. The longest processing time at any station is 12 seconds, meaning the average processing time per piece is 12 seconds. Compared to the existing production process shown in Table 2, this processing technology can significantly shorten processing time, improve production efficiency, and reduce production costs.

[0040]

[0041] Table 1

[0042] Table 2 Furthermore, such as Figure 5 As shown, the threaded relief groove of the valve cover serves both as a relief groove in the machining process and as a sealing ring mounting groove during use.

[0043] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0044] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A process for processing a gate valve cover, characterized in that, Includes the following steps: Step 1: Select 304 stainless steel wire for production. Use cold heading process to head the 304 stainless steel wire into the required valve cover blank. During the process, the clamping reference outer circle is extruded at the first end of the valve cover blank. The cold heading process consists of six steps. The first step is to form a stepped circle, shaping the uneven blank into a stepped circle. The second step is to press the blank into shape, obtaining a further stepped circle, and leaving a positioning hole at the center of the end face of the first end of the blank to facilitate the guidance of the mold in the next station. The third step is to form an inner hexagon and an outer hexagon through compound extrusion. The fourth step is to continue extrusion to obtain the inner hexagon and the outer clamping reference outer circle. The fifth step is to perform reverse extrusion to obtain the inner stepped process hole. The sixth step is to punch out the central through hole, finally obtaining the required stop valve cover blank. Step 2: Grind and clean the valve cover blank to remove surface oxide scale and dirt; Step 3: Based on the valve cover processing dimensions and time, select the first processing equipment and the second processing equipment to process both ends of the valve cover blank respectively, so that the processing time difference between the first processing equipment and the second processing equipment is less than 3 seconds; Step 4: Use the first processing equipment to clamp the clamping reference outer circle of the valve cover blank, process the second end of the valve cover blank, and directly process the second end to the required size of the finished product. Then use the second processing equipment to clamp the second end of the processed valve cover blank, process the first end of the valve cover blank, and directly process the first end to the required size of the finished product to obtain the finished valve cover. The first machining equipment has two machining spindles working simultaneously to machine the stepped circle and flange bevel of the second end respectively; the second machining equipment has multiple stations working simultaneously to machine the outer circle, outer groove, inner hole, inner hole chamfer and external thread of the first end in sequence. Step 5: Clean the finished valve cover and put it into storage to complete the production process.

2. The valve cover processing technology for a gate valve according to claim 1, characterized in that: In step one, 304 stainless steel wire of appropriate diameter is selected according to the size of the valve cover. The 304 stainless steel wire is heated to 500-800℃ by a high-frequency heater and then sent to a multi-station cold heading forming machine. The multi-station cold heading forming machine cuts, shapes, stretches, extrudes and punches the wire to produce the valve cover blank.

3. The valve cover processing technology for a gate valve according to claim 1, characterized in that: In step one, during cold heading, all non-rotating surface structures except for threads are cold-headed.

4. The valve cover processing technology for a gate valve according to claim 1, characterized in that: In step two, a three-dimensional vibratory grinding machine is used to thoroughly grind the valve cover blank to remove oxide scale and dirt from the surface of the blank.

5. The valve cover processing technology for a gate valve according to claim 1, characterized in that: In step three, the first processing equipment is a twin-spindle CNC lathe, and the second processing equipment is a multi-station combination CNC lathe.

6. The valve cover processing technology for a gate valve according to claim 1, characterized in that: In step four, the valve cover blanks processed by the first processing equipment are automatically transported to the elevator of the second processing equipment by a conveyor belt. The first processing equipment uses a feeding vibratory plate for feeding, while the second processing equipment uses a combination of a stepped pusher and a robotic arm for feeding.

7. The valve cover processing technology for a gate valve according to claim 1, characterized in that: In step five, an ultrasonic cleaner is used to clean the finished valve cover.

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