Multi-station energy-saving VPSA (Vacuum Pressure Swing Adsorption) biogas decarbonization and purification equipment

Abstract

The invention provides a multi-station energy-saving VPSA (vacuum pressure swing adsorption) method biogas decarbonization and purification device, which relates to the field of biogas purification, and comprises a mounting seat, an adsorption tower arranged on the mounting seat, a gas inlet pipe arranged on the adsorption tower, a connecting pipe arranged on the adsorption tower, and a compressor arranged on the mounting seat, in order to solve the problem that in the prior art, piston type buffering of an exhaust pipe of a compressor easily causes too high local temperature and possibly causes methane explosion, the buffering mechanism is arranged, the buffering mechanism drives the air bag to deform to buffer high-pressure pulse type methane, the situation that heat is generated by friction is avoided, and the service life of the high-pressure pulse type methane is prolonged. The safety of the equipment is improved; by arranging a buffer mechanism, the problem that in the prior art, an adsorbent is damaged due to moisture condensation is solved; by arranging a buffer mechanism, the problem of resource waste caused by methane heat loss in the prior art is solved; by arranging the buffer mechanism, the problem that the adsorption performance of an adsorbent in the prior art is reduced is solved.

Description

Technical Field

[0001] This invention relates to the field of biogas purification, and more specifically, to a multi-functional energy-saving VPSA biogas decarbonization and purification equipment. Background Technology

[0002] The multi-functional energy-saving VPSA biogas decarbonization and purification equipment uses vacuum pressure swing adsorption as its core technology to purify biogas, remove carbon dioxide, and improve methane purity.

[0003] Existing multi-functional energy-saving VPSA biogas decarbonization and purification equipment consists of a compressor, liquid-gas separator, biological desulfurization tower, activated carbon adsorption bed, membrane dryer, fine filter, gas buffer tank, terminal storage equipment, adsorption tower, and vacuum pump. The raw biogas undergoes pretreatment in the biological desulfurization tower and activated carbon adsorption bed before entering the adsorption tower for decarbonization and purification. The resulting methane is a low-pressure finished gas. The compressor is used to progressively compress this low-pressure, high-purity methane to the designed high-pressure conditions, ensuring the methane gas meets the pressure requirements for subsequent storage, pipeline connection, and vehicle filling. However, when the compressor discharges high-pressure methane into the terminal storage equipment, the methane gas flow from the compressor discharge pipe is pulsed. Existing systems use piston buffers to buffer the methane flow. Methane is a flammable and explosive gas; during buffering, the piston undergoes high-frequency reciprocating sliding friction, generating heat and causing a localized temperature increase in the discharge pipe. This not only accelerates the aging and failure of seals but also creates a high-temperature ignition source, potentially posing a safety hazard of methane explosion.

[0004] Therefore, we have made improvements to this and proposed a multi-functional, energy-saving VPSA biogas decarbonization and purification equipment. Summary of the Invention

[0005] The purpose of this invention is to address the problem that existing compressor exhaust pipe piston buffers can easily lead to excessively high local temperatures, which may cause methane explosions.

[0006] To achieve the above-mentioned objectives, this invention provides a multi-functional energy-saving VPSA biogas decarbonization and purification device to solve the aforementioned problems.

[0007] The application is as follows:

[0008] It includes a mounting base, an adsorption tower mounted on the mounting base, an inlet pipe mounted on the adsorption tower, a connecting pipe mounted on the adsorption tower, a compressor mounted on the mounting base, a discharge pipe mounted on the compressor, and a buffer mechanism mounted on the mounting base.

[0009] The buffer mechanism includes a hollow seat mounted on the mounting base, a connecting bottle mounted on the hollow seat, a pressure valve mounted inside the discharge pipe, a through hole mounted on the discharge pipe, an air bladder mounted on the through hole, and a water pump mounted on the mounting base.

[0010] As a preferred technical solution of this application, both the discharge pipe and the air inlet pipe are disposed on the hollow seat, the connecting bottle and the hollow seat are interconnected, and the output end of the water pump is disposed on the hollow seat.

[0011] As a preferred technical solution of this application, a piston is slidably disposed inside the connecting bottle, a transmission disc is disposed inside the connecting bottle, and a spring is disposed on the corresponding surface of the piston and the transmission disc.

[0012] As a preferred technical solution of this application, the transmission disk is slidably disposed inside the connecting bottle, a threaded post is rotatably disposed on the connecting bottle, the transmission disk is threadedly connected to the threaded post, and a knob is disposed on the threaded post.

[0013] As a preferred technical solution of this application, a drive seat is provided on the hollow seat, and a drive tube and a synchronization tube are provided on the drive seat. The drive tube and the synchronization tube are both connected to the hollow seat, and the connecting tube is provided on the hollow seat.

[0014] As a preferred technical solution of this application, a drive ring is slidably disposed inside the drive tube, a jacking tube is disposed inside the drive tube, a second spring is disposed on the corresponding surface of the drive ring and the jacking tube, a sealing ring is disposed on the drive tube, an output groove is disposed on the sealing ring, an output groove is disposed on the drive tube, an output groove is disposed on the drive tube, an output groove is disposed on the synchronization tube, a one-way valve is disposed on the synchronization tube, a transmission shaft is rotatably disposed on the drive ring, and a baffle is disposed on the transmission shaft.

[0015] As a preferred technical solution of this application, the sealing ring is slidably disposed on the drive tube, and the output slot one and the output slot two are mutually adapted.

[0016] As a preferred technical solution of this application, the baffle and the drive ring are connected by a torsion spring.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] In the scheme of this application:

[0019] 1. In order to solve the problem that the piston-type buffer in the compressor exhaust pipe of the prior art is prone to local overheating, which may cause methane explosion, this application sets up a buffer mechanism. The buffer mechanism drives the deformation of the gas bag to buffer the high-pressure pulse methane, thereby avoiding frictional heat generation and improving the safety of the equipment.

[0020] 2. By using a buffer mechanism, the circulating water is preheated to reduce condensation in the intake air and prevent liquid water from damaging the adsorbent, thereby improving the stability of adsorption and solving the problem of adsorbent damage caused by condensation in the prior art.

[0021] 3. By using a buffer mechanism, the heat from high-temperature methane is absorbed and transferred, thus realizing the recovery of methane heat, improving resource utilization, and solving the problem of resource waste caused by methane heat loss in existing technologies.

[0022] 4. By setting up a buffer mechanism to adjust the water pressure of the water pump, the thermal regeneration of the adsorbent is realized, the working efficiency of the equipment is improved, and the problem of reduced adsorption performance of the adsorbent in the existing technology is solved. Attached Figure Description

[0023] Figure 1 A schematic diagram of the structure of the multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided in this application;

[0024] Figure 2 A partial cross-sectional view of the hollow base of the multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided in this application;

[0025] Figure 3 The multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided in this application Figure 2 Enlarged structural diagram of area A in the middle;

[0026] Figure 4 A schematic diagram of the internal structure of the hollow base of the multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided in this application;

[0027] Figure 5 A schematic diagram of the internal structure of the synchronization pipe of the multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided in this application;

[0028] Figure 6 A partial cross-sectional view of the drive pipe of the multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided in this application;

[0029] Figure 7 A partial cross-sectional view of the baffle structure of the multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided in this application.

[0030] The image shows:

[0031] 1. Mounting base; 101. Adsorption tower; 102. Inlet pipe; 103. Connecting pipe; 104. Compressor; 105. Discharge pipe;

[0032] 2. Buffer mechanism; 201. Hollow seat; 202. Connecting bottle; 203. Pressure valve; 204. Through hole; 205. Airbag; 206. Water pump; 207. Piston; 208. Transmission disc; 209. Spring 1; 210. Threaded column; 211. Knob; 212. Drive seat; 213. Drive tube; 214. Synchronization tube; 215. Drive ring; 216. Pushing tube; 217. Spring 2; 218. Sealing ring; 219. Output slot 1; 220. Output slot 2; 221. Output slot 3; 222. Check valve; 223. Transmission shaft; 224. Baffle. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] As described in the background section, the piston-type buffer in the compressor exhaust pipe can easily lead to excessively high local temperatures, which may cause a methane explosion.

[0035] To address this technical problem, the present invention provides a multi-functional energy-saving VPSA biogas decarbonization and purification equipment, which is applied to biogas purification.

[0036] For details, please refer to Figure 1 - Figure 7 As shown, the multi-functional energy-saving VPSA biogas decarbonization and purification equipment specifically includes: a mounting base 1, an adsorption tower 101 mounted on the mounting base 1, an inlet pipe 102 mounted on the adsorption tower 101, a connecting pipe 103 mounted on the adsorption tower 101, a compressor 104 mounted on the mounting base 1, a discharge pipe 105 mounted on the compressor 104, and a buffer mechanism 2 mounted on the mounting base 1.

[0037] The buffer mechanism 2 includes a hollow seat 201 mounted on the mounting base 1, a connecting bottle 202 mounted on the hollow seat 201, a pressure valve 203 mounted in the discharge pipe 105, a through hole 204 mounted on the discharge pipe 105, an air bladder 205 mounted on the through hole 204, and a water pump 206 mounted on the mounting base 1.

[0038] The multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided by this invention addresses the problem in the prior art where the compressor 104 exhaust pipe piston 207 buffer can easily lead to excessively high local temperatures, which may cause methane explosions. This application provides a buffer mechanism 2, which drives the deformation of the airbag 205 to buffer the high-pressure pulsed methane, avoiding frictional heat generation and improving the safety of the equipment.

[0039] By using the buffer mechanism 2, the circulating water is preheated to the air inlet pipe 102, which reduces condensation in the air and prevents liquid water from damaging the adsorbent, thereby improving the stability of adsorption and solving the problem of condensation damaging the adsorbent in the prior art.

[0040] By using the buffer mechanism 2, the heat of high-temperature methane is absorbed and transferred, thereby realizing the recovery of methane heat, improving the utilization rate of resources, and solving the problem of resource waste caused by methane heat loss in the existing technology.

[0041] By setting up a buffer mechanism 2, the water pressure of the water pump 206 is adjusted through the buffer mechanism 2, which realizes the thermal regeneration of the adsorbent, improves the working efficiency of the equipment, and solves the problem of reduced adsorption performance of the adsorbent in the prior art.

[0042] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0043] It should be noted that, unless otherwise specified, the embodiments and features and technical solutions in the present invention can be combined with each other.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] Example 1, please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, a multi-functional energy-saving VPSA biogas decarbonization and purification device has an exhaust pipe 105 and an intake pipe 102 both installed on a hollow base 201, a connecting bottle 202 and a hollow base 201 connected to each other, and the output end of a water pump 206 installed on the hollow base 201.

[0046] In operation, the adsorption tower 101 is filled with a special adsorbent for decarbonizing and separating biogas. The compressor 104 compresses the methane. One end of the discharge pipe 105 is connected to the compressor 104, and the other end is connected to the existing terminal storage equipment. The compressor 104 compresses the methane, which is then output through the discharge pipe 105, resulting in a pulsed discharge of the compressed methane into the existing terminal storage equipment. The connecting pipe 103 is connected to the existing blower, which supplies ambient temperature air, which is then transported through the connecting pipe 103. This high-flow-rate, low-pressure airflow purges the adsorbent bed within the adsorption tower 101, assisting in adsorption desorption and regeneration. Figure 1 As shown, the inlet and outlet of the water pump 206 are connected to the hollow base 201 via rigid pipes, creating a circulating space inside the hollow base 201. The hollow base 201 is filled with water. When the water pump 206 is started, it circulates the water within the hollow base 201. The compressor 104 drives the methane discharged through the discharge pipe 105 to compress the gas bladder 205. The deformation of the gas bladder 205 buffers the high-pressure pulsed methane. When the gas bladder 205 inflates, it compresses the water inside the hollow base 201, causing the liquid level in the connecting bottle 202 to rise. Since the compressed methane is at a high temperature, the expansion of the air bladder 205 increases the contact area with water, allowing the water to cool the methane and absorb its heat. The circulating water preheats the intake pipe 102, reducing condensation and preventing liquid water from damaging the adsorbent, thus improving adsorption stability. The expansion of the air bladder 205 transfers the heat from the high-temperature methane, achieving heat recovery and improving resource utilization. The deformation of the air bladder 205 buffers the high-pressure pulsed methane, preventing frictional heat generation and improving equipment safety.

[0047] Furthermore, a piston 207 is slidably disposed inside the connecting bottle 202, a transmission disc 208 is disposed inside the connecting bottle 202, and a spring 209 is disposed on the corresponding surface of the piston 207 and the transmission disc 208.

[0048] Furthermore, the transmission disc 208 is slidably disposed inside the connecting bottle 202, and a threaded post 210 is rotatably disposed on the connecting bottle 202. The transmission disc 208 is threadedly connected to the threaded post 210, and a knob 211 is disposed on the threaded post 210.

[0049] By rotating knob 211, knob 211 drives threaded post 210 to rotate synchronously, and threaded post 210 drives transmission disc 208 to slide along connecting bottle 202, as... Figure 3As shown, the connecting bottle 202 is provided with a sliding groove, and the transmission disk 208 is provided with a protrusion. The protrusion slides along the sliding groove, so that the transmission disk 208 slides in a straight line along the connecting bottle 202. The transmission disk 208 slides to adjust the deformation of the spring 209. The piston 207 cannot be disengaged from the connecting bottle 202. The bottom of the connecting bottle 202 limits the piston 207 and communicates with the hollow seat 201. The expansion of the air bag 205 will drive the piston 207 to slide along the connecting bottle 202. By adjusting the deformation of the spring 209, the deformation of the air bag 205 is adjusted. According to the fluctuation of the actual working conditions, the pressure stabilization effect is always guaranteed.

[0050] The deformation of the airbag 205 driven by the buffer mechanism 2 buffers the high-pressure pulsed methane, avoiding frictional heat generation and improving equipment safety. The circulating water driven by the buffer mechanism 2 preheats the air inlet pipe 102, reducing condensation in the intake air and preventing liquid water from damaging the adsorbent, thus improving adsorption stability. The heat of the high-temperature methane is absorbed and transferred by the buffer mechanism 2, realizing heat recovery of methane and improving resource utilization.

[0051] Example 2 further optimizes the multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided in Example 1. Specifically, as follows: Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, a drive seat 212 is provided on the hollow seat 201, and a drive tube 213 and a synchronization tube 214 are provided on the drive seat 212. Both the drive tube 213 and the synchronization tube 214 are connected to the hollow seat 201, and a connecting tube 103 is provided on the hollow seat 201.

[0052] Furthermore, a drive ring 215 is slidably disposed inside the drive tube 213, a push tube 216 is disposed inside the drive tube 213, a second spring 217 is disposed on the corresponding surface of the drive ring 215 and the push tube 216, a sealing ring 218 is disposed on the drive tube 213, an output groove 219 is disposed on the sealing ring 218, an output groove 220 is disposed on the drive tube 213, an output groove 221 is disposed on the synchronization tube 214, a one-way valve 222 is disposed on the synchronization tube 214, a transmission shaft 223 is rotatably disposed on the drive ring 215, and a baffle 224 is disposed on the transmission shaft 223;

[0053] Furthermore, the sealing ring 218 is slidably mounted on the drive tube 213, and the output slot one 219 and the output slot two 220 are mutually adapted;

[0054] Furthermore, the baffle 224 and the drive ring 215 are connected by a torsion spring;

[0055] When water enters the drive pipe 213 from the hollow seat 201, the water squeezes the drive ring 215 and the baffle 224, causing the drive ring 215 and the sealing ring 218 to slide synchronously along the drive pipe 213. When the output slot 1 219 and the output slot 220 overlap, water enters the drive seat 212 from the overlap point, then enters the output slot 3 221 from the drive seat 212, and finally enters the synchronization pipe 214 from the output slot 3 221 and then into the hollow seat 201, completing a water cycle. By increasing the water pressure of the water pump 206, the drive ring 215 slides along the drive pipe 213, pushing the pipe 216 to squeeze the baffle 224. At this time, the baffle... 224 rotates and unfolds. At this time, the sealing ring 218 seals the output slot 220, allowing water to be discharged from the jacking pipe 216 and into the synchronization pipe 214 through the one-way valve 222, realizing a water circulation. The connecting pipe 103 is set on the hollow seat 201. The water circulation in the hollow seat 201 heats the connecting pipe 103. The water pressure of the hollow water pump 206 controls the heating of the connecting pipe 103. When the connecting pipe 103 needs to be heated, the water pressure can be increased. When the adsorption performance of the adsorbent decreases and thermal regeneration is required, the gas blown out by the blower must be heated. Thermal regeneration is achieved in this way.

[0056] By adjusting the water pressure of the water pump 206 through the buffer mechanism 2, the thermal regeneration of the adsorbent is achieved, thereby improving the working efficiency of the equipment.

[0057] The usage process of the multi-functional energy-saving VPSA biogas decarbonization and purification equipment provided by this invention is as follows:

[0058] In use, the water pump 206 is started, which drives the water in the hollow seat 201 to circulate. The compressor 104 drives the methane discharged from the discharge pipe 105 to compress the gas bladder 205. The deformation of the gas bladder 205 buffers the high-pressure pulsed methane. When the gas bladder 205 inflates, it compresses the water in the hollow seat 201. The water compression drives the piston 207, which slides along the connecting bottle 202. At this time, the liquid level in the connecting bottle 202 rises. Because the compressed methane is at a high temperature, it is lifted by the expansion of the gas bladder 205. The high contact area between the water and the methane allows the water to cool the methane and absorb its heat. The circulating water preheats the intake pipe 102, reducing condensation and preventing liquid water from damaging the adsorbent. The inflating airbag 205 transfers heat from the high-temperature methane, and the deformation of the airbag 205 buffers the high-pressure pulsed methane flow, preventing frictional heat generation. When water from the hollow seat 201 enters the drive pipe 213, it compresses the drive ring 215 and the baffle 224, causing the drive ring 215 and the sealing ring 218 to move synchronously along... When the drive tube 213 slides, and the output slot 1 219 and the output slot 220 overlap, water enters the drive seat 212 from the overlap point, then enters the output slot 3 221 from the drive seat 212, and finally enters the synchronization tube 214 from the output slot 3 221 and the hollow seat 201, thus completing a water cycle. By increasing the water pressure of the pump 206, the drive ring 215 slides along the drive tube 213, pushing the tube 216 to press the baffle 224. At this time, the baffle 224 rotates and unfolds, and the sealing ring 218 seals the output slot 220. This allows water to be discharged from the jacking pipe 216 and into the synchronization pipe 214 through the one-way valve 222, thus achieving a water circulation. The connecting pipe 103 is installed on the hollow seat 201. The water circulation in the hollow seat 201 heats the connecting pipe 103. The water pressure of the hollow water pump 206 controls the heating of the connecting pipe 103. When the connecting pipe 103 needs to be heated, the water pressure can be increased. When the adsorption performance of the adsorbent decreases and thermal regeneration is required, the gas blown out by the blower must be heated. Thermal regeneration is achieved in this way.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] Obviously, the embodiments described above are merely some embodiments of the present invention, not all embodiments. The accompanying drawings show preferred embodiments of the present invention, but do not limit the patent scope of the present invention. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. A multi-work energy-saving VPSA method biogas decarburization purification equipment, comprising a mounting seat (1), an adsorption tower (101) arranged on the mounting seat (1), an air inlet pipe (102) arranged on the adsorption tower (101), a connecting pipe (103) arranged on the adsorption tower (101), a compressor (104) arranged on the mounting seat (1), and a discharge pipe (105) arranged on the compressor (104), characterized in that, Includes a buffer mechanism (2) disposed on the mounting base (1); The buffer mechanism (2) includes a hollow seat (201) disposed on the mounting base (1), a connecting bottle (202) disposed on the hollow seat (201), a pressure valve (203) disposed in the discharge pipe (105), a through hole (204) disposed on the discharge pipe (105), an air bladder (205) disposed on the through hole (204), and a water pump (206) disposed on the mounting base (1).

2. The multi-functional energy-saving VPSA biogas decarbonization and purification equipment according to claim 1, characterized in that, The discharge pipe (105) and the air inlet pipe (102) are both located on the hollow seat (201), the connecting bottle (202) and the hollow seat (201) are interconnected, and the output end of the water pump (206) is located on the hollow seat (201).

3. The multi-functional energy-saving VPSA biogas decarbonization and purification equipment according to claim 2, characterized in that, A piston (207) is slidably disposed inside the connecting bottle (202), and a transmission disc (208) is disposed inside the connecting bottle (202). A spring (209) is disposed on the corresponding surface of the piston (207) and the transmission disc (208).

4. The multi-functional energy-saving VPSA biogas decarbonization and purification equipment according to claim 3, characterized in that, The transmission disc (208) is slidably disposed inside the connecting bottle (202), and a threaded post (210) is rotatably disposed on the connecting bottle (202). The transmission disc (208) is threadedly connected to the threaded post (210), and a knob (211) is disposed on the threaded post (210).

5. The multi-functional energy-saving VPSA biogas decarbonization and purification equipment according to claim 4, characterized in that, A drive seat (212) is provided on the hollow seat (201), and a drive tube (213) and a synchronization tube (214) are provided on the drive seat (212). The drive tube (213) and the synchronization tube (214) are both connected to the hollow seat (201), and the connecting tube (103) is provided on the hollow seat (201).

6. The multi-functional energy-saving VPSA biogas decarbonization and purification equipment according to claim 5, characterized in that, A drive ring (215) is slidably disposed inside the drive tube (213). A push tube (216) is disposed inside the drive tube (213). A second spring (217) is disposed on the corresponding surface of the drive ring (215) and the push tube (216). A sealing ring (218) is disposed on the drive tube (213). An output groove (219) is disposed on the sealing ring (218). An output groove (220) is disposed on the drive tube (213). An output groove (221) is disposed on the synchronization tube (214). A one-way valve (222) is disposed on the synchronization tube (214). A transmission shaft (223) is rotatably disposed on the drive ring (215). A baffle (224) is disposed on the transmission shaft (223).

7. The multi-functional energy-saving VPSA biogas decarbonization and purification equipment according to claim 6, characterized in that, The sealing ring (218) is slidably disposed on the drive tube (213), and the output slot one (219) and the output slot two (220) are adapted to each other.

8. The multi-functional energy-saving VPSA biogas decarbonization and purification equipment according to claim 7, characterized in that, The baffle (224) and the drive ring (215) are connected by a torsion spring.

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