Fermentation tank convenient to adjust and use and used for preparing and culturing mevalonic acid

Abstract

The utility model relates to the technical field of preparation and cultivation of melonic acid, in particular to a fermentation tank convenient to adjust and use for preparation and cultivation of melonic acid, which comprises a fermentation tank body, a cover plate arranged at the upper end of the fermentation tank body, a first feed pipe arranged on one side of the cover plate, a motor mounted on the upper side of the cover plate, and a rotating pipe arranged at the output end of the motor. The outer side of the rotating pipe is sleeved with a first annular piece, a plurality of first arc-shaped plates are arranged on the outer side of the first annular piece, a plurality of nozzles are formed in the first arc-shaped plates, and a PH detector is installed on the fermentation tank body. According to the utility model, a solution in the fermentation tank body can be detected in time through the PH detector, then ammonia water enters the cylinder, the ammonia water is discharged to the middle of the solution in the fermentation tank body through the plurality of nozzles, and the ammonia water and the solution are rapidly mixed through the rotation of the plurality of first arc-shaped plates, so that the PH value of the solution is rapidly adjusted.

Description

Technical Field

[0001] The utility model relates to the technical field of mevalonic acid preparation and bacterial cultivation, in particular to a mevalonic acid preparation and bacterial cultivation fermentation tank which is easy to adjust and use. Background Art

[0002] During the extraction of mevalonic acid, it is necessary to carry out mevalonic acid preparation and culture in a fermentation tank. However, during the process of mevalonic acid preparation and culture, it is necessary to control various factors such as dissolved oxygen value, pH value, glucose concentration, temperature, etc. in the entire fermentation tank in order to successfully culture the bacteria in the fermentation tank.

[0003] During the operation of the existing fermentation tank for preparing mevalonic acid and cultivating bacteria, when a pH deviation is detected, the pH value needs to be adjusted in the fermentation tank. However, the existing pH value adjustment is usually to pour ammonia water directly into the fermentation tank, so that the upper part of the solution in the fermentation tank contacts the ammonia water first, resulting in uneven mixing of raw materials and poor hierarchical structure, which affects the efficiency and quality of preparing mevalonic acid and cultivating bacteria. Utility Model Content

[0004] The utility model aims to provide a fermentation tank for preparing mevalonic acid and cultivating bacteria which is easy to adjust and use, so as to overcome the above-mentioned defects in the prior art.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a fermentation tank for preparing mevalonic acid and culturing bacteria that is easy to adjust and use, comprising a fermentation tank body, a cover plate is installed on the upper end of the fermentation tank body, a first feed pipe is fixedly installed on one side of the cover plate, the interior of the first feed pipe is connected to the interior of the fermentation tank body, a motor is installed in the middle of the upper side of the cover plate, a rotating tube is fixedly installed at the output end of the motor, a first annular member is sleeved on the outer side of the middle of the rotating tube, a plurality of first arc-shaped plates are fixedly arranged in a circular array on the outer side of the first annular member, the interior of each of the first arc-shaped plates is connected to the interior of the rotating tube, and each of the first arc-shaped plates is provided with a There are several nozzles, a cylinder is fixedly provided on the lower side of the cover plate, the interior of the cylinder is communicated with the interior of the rotating tube, a second feeding pipe is fixedly provided on the cover plate, the second feeding pipe is communicated with the interior of the cylinder, a control panel is installed on the outside of the fermentation tank body, a temperature sensor is installed on the fermentation tank body, a dissolved oxygen detector is installed on the fermentation tank body, a pH detector is installed on the fermentation tank body, a glucose concentration detector is installed on the fermentation tank body, a UV-visible detector is installed on the fermentation tank body, a spectrophotometer is installed on the fermentation tank body, and a heating plate is installed on the lower side of the interior of the fermentation tank body.

[0006] Among them, the control panel, temperature sensor, dissolved oxygen detector, pH detector, glucose concentration detector, UV-visible detector, and spectrophotometer are all prior art and will not be described in detail; the heating plate is used to heat the solution and is also prior art.

[0007] Preferably, a first ball valve is installed inside the first feed pipe, and a second ball valve is installed inside the second feed pipe. The first ball valve and the second ball valve are both prior art and will not be described in detail.

[0008] Preferably, a baffle is fixedly provided in the middle of the rotating tube, and the baffle is located at the same level as the lower edge of the first curved plate. The baffle is used to block the solution from falling to the lower side of the rotating tube, so that the solution in the rotating tube is at the same level as the lower edges of the first curved plates, so that the solution in the rotating tube can quickly enter the first curved plates, which is conducive to quickly adjusting various values ​​of the solution.

[0009] Preferably, two second annular members are sleeved on the outer side of the rotating tube, and the two second annular members are respectively located on the upper and lower sides of the first annular member, and a plurality of second arc plates are fixedly arranged in a circular array on the outer side of each second annular member, and the two second annular members are fixedly sleeved on the rotating tube.

[0010] Preferably, a plurality of stirring rods are fixedly disposed on the upper and lower sides of each second arc-shaped plate, wherein the second arc-shaped plate cooperates with the plurality of stirring rods to improve the efficiency of stirring the solution, so as to stir the solution evenly and improve the accuracy of solution detection.

[0011] Preferably, the outer side of the rotating tube is in sliding contact with the inner side of the cylinder, the outer side of the rotating tube located inside the cylinder is sleeved with a third annular member, and a plurality of stirring plates are arranged in a circumferential array on the outer side of the third annular member.

[0012] Preferably, a soft rubber fin is fixedly provided on the upper side of each stirring plate, the interior of the third annular member is connected with the interior of the cylinder, the interior of the third annular member is connected with the interior of the rotating tube, and four support rods are fixedly provided at the lower end of the fermentation tank body.

[0013] Preferably, an air inlet pipe is provided on one side of the lower part of the fermentation tank body, a one-way valve is provided between the inside of the air inlet pipe and the inside of the fermentation tank body, a third ball valve is provided between the inside of the air pipe and the outside of the fermentation tank body, and an exhaust valve is provided on the cover plate. The third ball valve is used to control whether the air inlet pipe is opened for ventilation, the one-way valve is used to prevent the solution in the fermentation tank body from entering the air inlet pipe, and the exhaust valve is used to exhaust air.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] The utility model can first set the pH value on the control panel, then timely check the solution in the fermentation tank body through the pH detector and feed back to the control panel, then open the second ball valve to allow ammonia water to enter the cylinder through the second feed pipe, and preliminarily stir the ammonia water in the cylinder through the rotation of a plurality of stirring plates and the rotation of a plurality of soft rubber fins; the ammonia water after the preliminary stirring enters the rotating tube through the third annular member, and the ammonia water falls onto the baffle plate in the rotating tube, and at this time, the rotating tube rotates to throw the ammonia water in the rotating tube into a plurality of first curved plates through centrifugal force, and the ammonia water in the plurality of first curved plates is then discharged to the middle of the solution in the fermentation tank body through a plurality of nozzles, and then the ammonia water is quickly mixed with the solution in the fermentation tank body through the rotation of the plurality of first curved plates, so that the pH of the solution in the fermentation tank body is kept at 7.0.

[0016] The utility model can first detect that the glucose concentration in the fermentation tank body is 0g / L through the glucose concentration detector, at this time the second ball valve is opened, and the staff puts 50% of the glucose solution into the cylinder through the second feeding pipe, and the rotation of the rotating tube drives the rotation of the plurality of stirring plates, and the glucose solution in the cylinder is initially stirred and uniformly through the rotation of the plurality of stirring plates and the rotation of the plurality of soft rubber fins; then the glucose solution in the cylinder enters the rotating tube through the third annular member, and the glucose solution falls onto the baffle in the rotating tube, and at this time the rotating tube rotates to throw the glucose solution in the rotating tube into the plurality of first curved plates through centrifugal force, and the glucose solution in the plurality of first curved plates is then discharged to the middle of the solution in the fermentation tank body through the plurality of nozzles, and then the glucose solution is quickly mixed with the solution in the fermentation tank body through the rotation of the plurality of first curved plates, so as to maintain the glucose concentration within the range of 0-10g / L.

[0017] The utility model can check the optical density of the bacteria through a spectrophotometer. When the optical density (OD600) of the bacteria reaches 30, the staff adds IPTG (isopropyl-β-D-thiogalactoside) into the cylinder through the second feeding pipe, and the IPTG in the cylinder enters the rotating tube through the third ring member. The IPTG falls onto the baffle in the rotating tube, and then the IPTG is thrown into a plurality of first arc-shaped plates through the centrifugal force of the rotating tube. Finally, the IPTG is discharged into the fermentation tank body through a plurality of nozzles. The concentration of the IPTG in the fermentation tank body is then checked through a visible detector, and a proper amount of IPTG is added into the second feeding pipe in time, so as to ensure that the concentration of the IPTG in the culture medium should be 0.5 millimoles per liter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The utility model is further explained below in conjunction with the accompanying drawings and embodiments:

[0019] Figure 1It is an isometric structural schematic diagram of the utility model.

[0020] Figure 2 It is a schematic diagram of the top view structure of the utility model.

[0021] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle.

[0022] Figure 4 It is a front view structural schematic diagram of the utility model.

[0023] Figure 5 for Figure 4 Schematic diagram of the cross-sectional structure at BB in the middle.

[0024] Figure 6 for Figure 4 Schematic diagram of the cross-sectional structure at CC in the middle.

[0025] Figure 7 It is an isometric structural schematic diagram of the internal structure of the fermentation tank body in the utility model.

[0026] In the figure, the fermentation tank body 10, the support rod 11, the control panel 12, the cover plate 13, the motor 14, the first feed pipe 15, the first ball valve 16, the second feed pipe 17, the second ball valve 18, the exhaust valve 19, the rotating tube 20, the second annular member 21, the second curved plate 22, the stirring rod 23, the first annular member 24, the first curved plate 25, the nozzle 26, the baffle 27, the cylinder 28, the third annular member 29, the stirring plate 30, the soft rubber fin 31, the UV-visible detector 32, the spectrophotometer 33, the temperature sensor 34, the dissolved oxygen detector 35, the pH detector 36, the glucose concentration detector 37, the heating plate 38, the air inlet pipe 39, the one-way valve 40, and the third ball valve 41. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this article includes any and all combinations of one or more related listed items.

[0029] See also Figure 1-7 The utility model provides a technical solution: a fermentation tank for preparing mevalonic acid and culturing bacteria, which is easy to adjust and use, comprises a fermentation tank body 10, a cover plate 13 is installed on the upper end of the fermentation tank body 10, a first feed pipe 15 is fixedly installed on one side of the cover plate 13, the interior of the first feed pipe 15 is communicated with the interior of the fermentation tank body 10, a motor 14 is installed in the middle of the upper side of the cover plate 13, a rotating tube 20 is fixedly installed at the output end of the motor 14, a first ring member 24 is sleeved on the outer side of the middle part of the rotating tube 20, a plurality of first arc plates 25 are fixedly arranged on the outer circumferential array of the first ring member 24, the interior of each first arc plate 25 is communicated with the interior of the rotating tube 20, and a plurality of nozzles 26 are arranged on each first arc plate 25, A cylinder 28 is fixedly provided on the lower side of the cover plate 13, and the interior of the cylinder 28 is connected to the interior of the rotating tube 20. A second feeding pipe 17 is fixedly provided on the cover plate 13, and the second feeding pipe 17 is connected to the interior of the cylinder 28. A control panel 12 is installed on the outside of the fermenter body 10, a temperature sensor 34 is installed on the fermenter body 10, a dissolved oxygen detector 35 is installed on the fermenter body 10, a pH detector 36 is installed on the fermenter body 10, a glucose concentration detector 37 is installed on the fermenter body 10, a UV-visible detector 32 is installed on the fermenter body 10, a spectrophotometer 33 is installed on the fermenter body 10, and a heating plate 38 is installed on the lower side of the inside of the fermenter body 10.

[0030] Further, such as Figure 3 As shown, a first ball valve 16 is installed inside the first feed pipe 15 , and a second ball valve 18 is installed inside the second feed pipe 17 .

[0031] Further, such as Figure 3 As shown, a baffle plate 27 is fixedly provided in the middle of the rotating tube 20 , and the baffle plate 27 is located at the same horizontal height as the lower edge of the first arc-shaped plate 25 .

[0032] Further, such as Figure 3 , Figure 7 As shown, two second annular members 21 are sleeved on the outer side of the rotating tube 20. The two second annular members 21 are respectively located on the upper and lower sides of the first annular member 24. A plurality of second arc plates 22 are fixedly arranged in a circular array on the outer side of each second annular member 21. Both second annular members 21 are fixedly sleeved on the rotating tube 20.

[0033] Further, such as Figure 3 , Figure 7 As shown, a plurality of stirring rods 23 are fixedly disposed on the upper and lower sides of each second arc-shaped plate 22 .

[0034] Further, such as Figure 3 , Figure 7As shown, the outer side of the rotating tube 20 is in sliding contact with the inner side of the cylinder 28 , and a third annular member 29 is sleeved on the outer side of the rotating tube 20 located inside the cylinder 28 , and a plurality of stirring plates 30 are arranged in a circumferential array on the outer side of the third annular member 29 .

[0035] Further, such as Figure 1-3 , Figure 6-7 As shown, a soft rubber fin 31 is fixedly provided on the upper side of each stirring plate 30 , the interior of the third annular member 29 is connected with the interior of the cylinder 28 , the interior of the third annular member 29 is connected with the interior of the rotating tube 20 , and four support rods 11 are fixedly provided at the lower end of the fermentation tank body 10 .

[0036] Further, such as Figure 3 As shown, an air inlet pipe 39 is provided on one side of the lower part of the fermentation tank body 10, the interior of the air inlet pipe 39 is connected to the interior of the fermentation tank body 10 and is provided with a one-way valve, the interior of the air pipe 39 is connected to the exterior of the fermentation tank body 10 and is provided with a third ball valve 41, and an exhaust valve 19 is provided on the cover plate 13.

[0037] When in use, a first-class seed solution with good growth is selected and inoculated into the fermentation tank body 10 at a 3% inoculation rate. At this time, the fermentation tank body 10 has been verified to be sterile by microscopic examination. Then, the initial speed of the motor 14 is set to 300 revolutions per minute (r / min) on the control panel 12. The motor 14 is started to drive the rotating tube 20 to rotate. The rotating tube 20 rotates through the two second ring members 21 to respectively drive the second curved plates 22 to rotate, so that the solution in the fermentation tank body 10 is fully stirred by the rotation of the second curved plates 22 and the stirring rods 23. The staff sets the temperature to 32°C on the control panel 12. , the temperature in the fermentation tank body 10 is timely detected by the temperature sensor 34, and the solution in the fermentation tank body 10 is heated by the heating plate 38, so that the temperature in the fermentation tank body 10 is maintained at 32°C; finally, the ventilation ratio is set to 1:1 on the control panel 12, and the control panel 12 controls the third ball valve 41 to open, so that the air outside the fermentation tank body 10 enters the bottom of the fermentation tank body 10 through the air inlet pipe 39, so that the air enters from the bottom of the fermentation tank body 10, so that the air can fully contact with the solution in the fermentation tank body 10; after the air floats to the surface of the liquid, it is finally discharged through the exhaust valve 19. Then, the dissolved oxygen level in the fermentation tank body 10 is timely detected by the dissolved oxygen detector 35, so as to ensure sufficient oxygen supply and ensure that the dissolved oxygen content is controlled at more than 30%.

[0038] When the pH detector 36 detects that the pH value of the solution in the fermentation tank body 10 is deviated, the second ball valve 18 is opened, and the staff feeds the ammonia water into the cylinder 28 through the second feed pipe 17; at this time, the rotating tube 20 rotates to drive the plurality of stirring plates 30 to rotate, and the ammonia water in the cylinder 28 is initially stirred and uniformly through the rotation of the plurality of stirring plates 30 and the rotation of the plurality of soft rubber fins 31; the initially stirred ammonia water enters the rotating tube 20 through the third annular member 29, and the ammonia water falls onto the baffle 27 in the rotating tube 20. The rotating tube 20 rotates to throw the ammonia water in the rotating tube 20 into the plurality of first curved plates 25 by centrifugal force, and the ammonia water in the plurality of first curved plates 25 is then discharged to the middle of the solution in the fermentation tank body 10 through the plurality of nozzles 26, and then the ammonia water is quickly mixed with the solution in the fermentation tank body 10 by the rotation of the plurality of first curved plates 25, and finally the solution in the fermentation tank body 10 is fully stirred and mixed by the rotation of the plurality of second curved plates 22 and the plurality of stirring rods 23, so that the pH value of the solution in the fermentation tank body 10 is maintained at 7.0.

[0039] After the initial glucose is exhausted, when the glucose concentration detector 37 detects that the glucose concentration in the fermentation tank body 10 is 0g / L, the second ball valve 18 is opened, and the staff puts 50% of the glucose solution into the cylinder 28 through the second feeding pipe 17. At this time, the rotating tube 20 rotates to drive the plurality of stirring plates 30 to rotate, and the glucose solution in the cylinder 28 is initially stirred uniformly by the rotation of the plurality of stirring plates 30 and the rotation of the plurality of soft rubber fins 31; then the glucose solution in the cylinder 28 enters the rotating tube 20 through the third annular member 29, and the glucose solution in the rotating tube 20 is stirred uniformly. The glucose solution in the rotating tube 20 falls onto the baffle 27, and the rotating tube 20 rotates to throw the glucose solution in the rotating tube 20 into the plurality of first curved plates 25 by centrifugal force. The glucose solution in the plurality of first curved plates 25 is then discharged to the middle of the solution in the fermentation tank body 10 through the plurality of nozzles 26, and then the plurality of first curved plates 25 rotate to make the glucose solution quickly mix with the solution in the fermentation tank body 10. Finally, the plurality of second curved plates 22 and the plurality of stirring rods 23 rotate to fully stir and mix the solution in the fermentation tank body 10 to maintain the glucose concentration in the range of 0-10 g / L.

[0040] The optical density of the bacteria is checked by a spectrophotometer 33. When the optical density (OD600) of the bacteria reaches 30, the staff adds IPTG (isopropyl-β-D-thiogalactoside) into the cylinder 28 through the second feed pipe 17. The IPTG in the cylinder 28 enters the rotating tube 20 through the third ring member 29. The IPTG falls onto the baffle 27 in the rotating tube 20, and then the rotating tube 20 rotates to throw the IPTG into the first curved plates 25 by centrifugal force. Finally, the IPTG is discharged into the fermenter body 10 through the nozzles 26. The concentration of IPTG in the fermenter body 10 is checked by the UV-visible detector 32, and an appropriate amount of IPTG is added to the second feed pipe 17 in time. Finally, the solution in the fermenter body 10 is fully stirred and mixed by the rotation of the second curved plates 22 and the stirring rods 23, so as to ensure that the concentration of IPTG in the culture medium should be 0.5 mmol per liter.

[0041] IPTG was used to induce the bacteria. During the induction period, 50% glucose solution was continuously added to maintain the glucose concentration within the range of 0-5g / L. Sugar compression treatment was performed after the bacterial growth stabilized: when the fermentation reached the first stable OD value and the sugar addition was very low and only maintained the normal growth of the bacteria, it lasted for 4-5 hours. After that, sugar compression treatment was performed, that is, the glucose concentration in the culture medium was adjusted to optimize the bacterial growth and the production of metabolites, and the glucose concentration was increased to about 5-10g / L to promote further bacterial growth and increase the MVA yield. After about 63 hours of induction, the MVA yield reached the highest level, and the fermentation broth could be subjected to subsequent extraction and purification steps.

[0042] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the appended claims and their equivalents.

Claims

1. A fermentation tank for preparing mevalonic acid and cultivating bacteria, which is easy to adjust and use, comprises a fermentation tank body (10), characterized in that: A cover plate (13) is installed at the upper end of the fermentation tank body (10), a first feed pipe (15) is fixedly installed on one side of the cover plate (13), the interior of the first feed pipe (15) is communicated with the interior of the fermentation tank body (10), a motor (14) is installed in the middle of the upper side of the cover plate (13), a rotating tube (20) is fixedly installed at the output end of the motor (14), a first ring member (24) is sleeved on the outer side of the middle part of the rotating tube (20), a plurality of first arc plates (25) are fixedly installed in a circumferential array on the outer side of the first ring member (24), the interior of each of the first arc plates (25) is communicated with the interior of the rotating tube (20), and each of the first arc plates (25) is provided with a plurality of nozzles (26), a cylinder (28) is fixedly installed on the lower side of the cover plate (13), the interior of the cylinder (28) is connected to the interior of the rotating tube (20), and a plurality of nozzles (26) are provided on the first arc plates (25). The fermenter body (10) is connected to the interior of the rotating tube (20), a second feed pipe (17) is fixedly provided on the cover plate (13), and the second feed pipe (17) is connected to the interior of the cylinder (28), a control panel (12) is installed on the outside of the fermenter body (10), a temperature sensor (34) is installed on the fermenter body (10), a dissolved oxygen detector (35) is installed on the fermenter body (10), a pH detector (36) is installed on the fermenter body (10), a glucose concentration detector (37) is installed on the fermenter body (10), an ultraviolet-visible detector (32) is installed on the fermenter body (10), a spectrophotometer (33) is installed on the fermenter body (10), and a heating plate (38) is installed on the lower side of the fermenter body (10).

2. A fermentation tank for preparing mevalonic acid and cultivating bacteria that is easy to adjust according to claim 1, characterized in that: A first ball valve (16) is installed inside the first feed pipe (15), and a second ball valve (18) is installed inside the second feed pipe (17).

3. A fermentation tank for preparing mevalonic acid and cultivating bacteria that is easy to adjust according to claim 1, characterized in that: A baffle plate (27) is fixedly provided in the middle of the rotating tube (20), and the baffle plate (27) is located at the same horizontal height as the lower edge of the first arc-shaped plate (25).

4. A fermentation tank for preparing mevalonic acid and cultivating bacteria that is easy to adjust according to claim 1, characterized in that: Two second annular members (21) are sleeved on the outer side of the rotating tube (20), and the two second annular members (21) are respectively located on the upper and lower sides of the first annular member (24), and a plurality of second arc-shaped plates (22) are fixedly arranged in a circular array on the outer side of each second annular member (21), and the two second annular members (21) are fixedly sleeved on the rotating tube (20).

5. A fermentation tank for preparing mevalonic acid and cultivating bacteria that is easy to adjust according to claim 4, characterized in that: A plurality of stirring rods (23) are fixedly disposed on the upper and lower sides of each of the second arc-shaped plates (22).

6. The fermentation tank for preparing mevalonic acid and cultivating bacteria that is easy to adjust according to claim 1, characterized in that: The outer side of the rotating tube (20) is in sliding contact with the inner side of the cylinder (28); the outer side of the rotating tube (20) located inside the cylinder (28) is sleeved with a third annular member (29); and a plurality of stirring plates (30) are arranged in a circular array on the outer side of the third annular member (29).

7. A fermentation tank for preparing mevalonic acid and cultivating bacteria that is easy to adjust according to claim 6, characterized in that: A soft rubber fin (31) is fixedly provided on the upper side of each stirring plate (30), the interior of the third annular member (29) is connected to the interior of the cylinder (28), the interior of the third annular member (29) is connected to the interior of the rotating tube (20), and four support rods (11) are fixedly provided at the lower end of the fermentation tank body (10).

8. The fermentation tank for preparing mevalonic acid and cultivating bacteria that is easy to adjust according to claim 1, characterized in that: An air inlet pipe (39) is provided on one side of the lower part of the fermentation tank body (10); the interior of the air inlet pipe (39) is connected to the interior of the fermentation tank body (10) and is provided with a one-way valve; the interior of the air pipe (39) is connected to the exterior of the fermentation tank body (10) and is provided with a third ball valve (41); and an exhaust valve (19) is provided on the cover plate (13).

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