Metering pump flow detection table

Abstract

The utility model relates to the technical field of test equipment, and discloses a metering pump flow detection table, which comprises a rack, a waste liquid box, a test liquid path, a metering pump placing table, a clamping mechanism and a metering pump driving mechanism, and the waste liquid box, the test liquid path, the metering pump placing table, the clamping mechanism and the metering pump driving mechanism are arranged on the rack. A measuring cup placing position is arranged on a testing platform on the rack; the input end of the test liquid path is communicated with the waste liquid tank, the first output end is arranged above the measuring cup placing position, the second output end is communicated with the waste liquid tank, and a flowmeter is arranged on the test liquid path. The metering pump placing table is used for placing a metering pump to be detected, and a liquid inlet nozzle and a liquid outlet nozzle of the clamping mechanism are respectively arranged on two sides of the metering pump placing table and can be respectively pressed on a liquid inlet and a liquid outlet of the metering pump under the driving of the clamping driving mechanism. The liquid inlet nozzle is communicated with the test liquid path, and the liquid outlet nozzle is communicated with the first output end and the second output end through the first control valve. The metering pump driving mechanism is used for driving the metering pump to be tested to work. The detection platform can improve the accuracy and efficiency of metering pump detection.

Description

Technical Field

[0001] The utility model relates to the technical field of testing equipment, in particular to a flow detection platform for a metering pump. Background Art

[0002] Metering pumps are commonly used in biological, pharmaceutical, and chemical industries. In demanding processes, precise testing of the pump's flow rate range is essential to ensure the accuracy of the volume of liquid delivered. Existing flow rate testing equipment for metering pumps requires manual integration of the pump into the system. This typically involves rotating the pump a preset number of times and measuring the amount of liquid pumped through a metering cup. This testing process is time-consuming, and the results are affected by the cleanliness of the cup, resulting in low accuracy. Utility Model Content

[0003] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a flow detection station for a metering pump, which can improve the detection efficiency and detection accuracy of the metering pump.

[0004] In order to solve the above problems, the technical solution adopted by the present invention is as follows: a metering pump flow detection platform, comprising: a frame, provided with a horizontal test platform, the test platform is provided with a measuring cup placement position; a waste liquid tank, arranged in the frame, for holding the liquid for testing; a test liquid circuit, arranged in the frame, the input end is connected to the waste liquid tank, the first output end is arranged above the measuring cup placement position, the second output end is connected to the waste liquid tank, and the test liquid circuit is provided with a flow meter; a metering pump placement platform, arranged above the test platform, for placing the metering pump to be tested; a clamping mechanism, comprising a liquid inlet nozzle, a liquid outlet nozzle and a clamping drive mechanism, the liquid inlet nozzle and the liquid outlet nozzle are respectively arranged on the metering pump On both sides of the placement table, the clamping drive mechanism is used to adjust the distance between the liquid inlet nozzle and the liquid outlet nozzle, so that the liquid inlet nozzle is pressed against the liquid inlet of the metering pump to be tested, and the liquid outlet nozzle is pressed against the liquid outlet of the metering pump to be tested, the liquid inlet nozzle is connected with the test liquid path, and the liquid outlet nozzle is connected with the first output end and the second output end through a first control valve, and the liquid flowing through the metering pump to be tested is discharged from the first output end into the measuring cup at the measuring cup placement position, or returned from the second output end to the waste liquid tank by controlling the first control valve; the metering pump drive mechanism is arranged on one side of the metering pump placement table, and is used to drive the metering pump to be tested placed on the metering pump placement table to work.

[0005] Compared to the existing technology, the present invention has the following advantages: a clamping mechanism can automatically connect a metering pump to be tested, placed on a metering pump placement table, to the test fluid circuit, thereby improving metering pump testing efficiency. When rapid batch measurement is required, the flow rate range of the metering pump can be directly and quickly read out using the flow meter on the test fluid circuit. When spot-checking the flow pump, the first control valve can be controlled to discharge the liquid passing through the metering pump through the first output port into the metering cup on the measuring cup placement position. The accuracy of the test result can be determined by comparing the liquid volume in the metering cup with the reading on the flow meter, thereby improving the accuracy of the flow rate range detection of the metering pump.

[0006] The above-mentioned metering pump flow detection platform, the clamping drive mechanism includes a clamping motor, a clamping screw pair, a fixed bracket and a movable bracket, the fixed bracket is fixedly arranged on the side of the metering pump placement platform away from the liquid inlet nozzle, the clamping screw pair is horizontally arranged on the fixed bracket, a plurality of guide rods are arranged on the fixed bracket, the movable bracket wraps the guide block and the liquid nozzle bracket, the guide block is connected to the screw nut of the clamping screw pair, the guide block is slidably connected to the guide rod through a linear bearing, the guide block is connected to the liquid nozzle bracket through a connecting column, the liquid outlet nozzle is arranged on the liquid nozzle connecting plate, a plurality of elastic parts are arranged between the liquid nozzle connecting plate and the liquid nozzle bracket, the screw of the clamping screw pair is transmission-connected to the output shaft of the clamping motor.

[0007] In the above-mentioned metering pump flow detection platform, a pressure sensor is provided between the liquid nozzle connecting plate and the liquid nozzle bracket.

[0008] The above-mentioned metering pump flow detection platform, the metering pump drive mechanism includes a drive motor, a transmission shaft and a drive gear, the transmission shaft is rotatably arranged on one side of the metering pump placement platform, the transmission shaft is transmission-connected to the output shaft of the drive motor, the drive gear is arranged on the transmission shaft, and the drive gear can engage with the external drive gear of the metering pump to be tested placed on the metering pump placement platform.

[0009] The metering pump flow detection station is provided with a label printer on the frame, and the label printer is used to print labels according to the test results of the metering pump.

[0010] In the above-mentioned metering pump flow detection station, a temperature sensor and a liquid level sensor are provided in the waste liquid tank.

[0011] The above-mentioned metering pump flow detection platform is provided with a waste liquid recovery funnel under the measuring cup placement position and the metering pump placement platform. A support net is provided at the inlet of the waste liquid recovery funnel, and the outlet of the waste liquid recovery funnel is connected to the waste liquid tank.

[0012] The above-mentioned metering pump flow detection platform is further provided with an emptying liquid circuit in the frame, the inlet and outlet of the emptying liquid circuit are both connected to the waste liquid tank, a liquid pump is connected in series on the emptying liquid circuit, the liquid inlet nozzle is connected to the test liquid circuit and the emptying liquid circuit through a second control valve, and the liquid inlet nozzle is connected to the test liquid circuit or the emptying liquid circuit by controlling the second control valve.

[0013] In the above-mentioned metering pump flow detection station, a first pressure gauge is provided on the emptying liquid path, and a second pressure gauge is provided between the liquid outlet nozzle and the first control valve.

[0014] In the above-mentioned metering pump flow detection station, a first overflow valve is provided on the emptying liquid path, and a second overflow valve is provided between the liquid outlet nozzle and the first control valve.

[0015] The present invention will be described in further detail below with reference to the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a front view of a metering pump flow detection platform according to an embodiment of the present utility model;

[0017] Figure 2 A top view of a test platform according to an embodiment of the present invention;

[0018] Figure 3 A front view of a test platform according to an embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of the test fluid circuit according to an embodiment of the present utility model.

[0020] Description of Figure Numbers:

[0021] 100 rack, 110 test platform, 111 measuring cup placement position, 112 waste liquid recovery funnel, 120 first output end, 130 display screen, 140 pressure gauge, 150 overflow valve handle, 200 metering pump placement table, 300 clamping mechanism, 310 clamping motor, 320 fixed bracket, 321 guide rod, 322 clamping screw pair, 333 connecting column, 3311 elastic part, 3312 pressure sensor, 330 movable bracket, 331 liquid nozzle bracket, 332 guide block, 340 liquid outlet nozzle, 350 liquid inlet nozzle, 400 metering pump drive mechanism, 410 drive motor, 420 transmission shaft, 430 drive gear, 500 label printer. DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described in detail below. Figure 1 and Figure 4An embodiment of the present invention provides a metering pump flow detection station, comprising a frame 100 and a waste liquid tank, a test liquid circuit, a metering pump placement platform 200, a clamping mechanism 300, and a metering pump drive mechanism 400 arranged on the frame 100. A horizontal test platform 110 is provided on the frame 100, and a measuring cup placement position 111 for placing a measuring cup is provided on the test platform 110. The waste liquid tank and the test liquid circuit are arranged inside the frame 100, and the waste liquid tank is used to hold the liquid for testing. The input end of the test liquid circuit is connected to the waste liquid tank and has two output ends, wherein the first output end 120 is arranged above the measuring cup placement position 111, and the outflowing liquid can enter the measuring cup placed on the measuring cup placement position 111; the second output end is connected to the waste liquid tank and returns the liquid to the waste liquid tank. The metering pump placement platform 200 is arranged above the test platform 110 and is used to place the metering pump to be tested. The clamping mechanism 300 includes a liquid inlet nozzle 350, a liquid outlet nozzle 340, and a clamping drive mechanism. The liquid inlet nozzle 350 and the liquid outlet nozzle 340 are respectively arranged on both sides of the metering pump placement platform 200. The liquid inlet nozzle 350 is connected to the waste liquid tank through the test liquid circuit, and the liquid outlet nozzle 340 is connected to the first output section and the second output end through the first control valve GA. The clamping drive mechanism is used to adjust the distance between the liquid inlet nozzle 350 and the liquid outlet nozzle 340 so that the liquid inlet nozzle 350 is pressed against the liquid inlet of the metering pump to be tested, and the liquid outlet nozzle 340 is pressed against the outlet of the metering pump to be tested, thereby connecting the metering pump to the test liquid circuit. By controlling the first control valve GA, the liquid passing through the metering pump to be tested can be controlled to flow from the first output end 120 into the measuring cup, or directly flow back into the waste liquid tank through the second output end. The metering pump driving mechanism 400 is disposed on one side of the metering pump placement table 200 and is used to drive the metering pump to be tested placed on the metering pump placement table 200 to operate.

[0023] The metering pump flow detection station of the embodiment of the present utility model can automatically connect the metering pump to be tested to the test liquid circuit through the clamping mechanism 300, thereby improving the detection efficiency of the metering pump. In addition, the flow of the metering pump is directly read out by the flow meter FT. Compared with the detection method using a metering cup, the detection accuracy will not be affected by the cleanliness of the metering cup. The detection efficiency and accuracy are higher, and high-precision batch detection of multiple metering pumps can be completed quickly. During random inspections, the liquid outlet 340 can be connected to the first output end 120 by controlling the action of the first control valve GA, so that the liquid pumped out by the metering pump flows into the metering cup. The accuracy of the detection result can be determined by comparing the readings of the metering cup and the flow meter FT. The detection accuracy can be guaranteed by comparing the flow ranges measured by the metering cup and the flow meter FT.

[0024] Reference Figure 2 and Figure 3In this embodiment, the clamping drive mechanism includes a clamping motor 310, a clamping screw pair 322, a fixed bracket 320, and a movable bracket 330. The fixed bracket 320 is fixedly mounted on the side of the metering pump placement platform 200 facing away from the oil inlet. It includes a base plate vertically mounted on the frame 100 and side plates vertically mounted on the left and right ends of the base plate. The clamping screw pair 322 is horizontally mounted on the base plate. Two guide rods 321 are horizontally mounted between the two side plates, and the two guide rods 321 are respectively mounted at the upper and lower ends of the side plates. The movable bracket 330 includes a guide block 332 and a liquid nozzle bracket 331. Linear bearings are provided at both ends of the guide block 332. The two ends of the guide block 332 are slidably set on the two guide rods 321 through two linear bearings. The guide block 332 is connected to the liquid nozzle bracket 331 through two connecting columns 333. Two linear bearings are provided on the side panel on the right. The ends of the two connecting columns 333 facing away from the guide block 332 pass through the linear bearings on the two side panels and are connected to the liquid nozzle bracket 331. The guide block 332 is connected to the screw nut of the clamping screw pair 322. The screw of the clamping screw pair 322 is connected to the output shaft of the clamping motor 310 through a synchronous belt mechanism. In this embodiment, the liquid inlet nozzle 350 is fixed to the right side of the metering pump placement platform 200 via a liquid nozzle holder. The liquid outlet nozzle 340 is attached to the liquid nozzle bracket 331 via a liquid nozzle connecting plate. Several elastic members 3311 are positioned between the liquid nozzle connecting plate and the liquid nozzle bracket 331 to provide a buffer, preventing damage to the metering pump or liquid nozzle due to excessive pressure. In this embodiment, the elastic members 3311 are compression springs. The four legs of the liquid nozzle bracket 331 are provided with four apertures, each of which is equipped with a bolt. The liquid nozzle bracket 331 is connected to the liquid nozzle connecting plate via four bolts, and the four compression springs are respectively mounted on the four bolts. A pressure sensor 3312 is also positioned between the liquid nozzle connecting plate and the liquid nozzle bracket 331 to detect the pressure between the liquid nozzle and the metering pump, thereby facilitating adjustment of the pressure between the liquid nozzle and the metering pump to ensure a good seal between the liquid nozzle and the metering pump while preventing damage to the metering pump. It is understood that in some embodiments, the positions of the liquid outlet nozzle 340 and the liquid inlet nozzle 350 can be interchanged.

[0025] Reference Figure 2 and Figure 3In this embodiment, the metering pump drive mechanism 400 includes a drive motor 410, a transmission shaft 420, and a drive gear 430. The transmission shaft 420 is rotatably mounted on the frame 100 via two bearing blocks at both ends. The transmission shaft 420 is horizontally mounted on the rear side of the metering pump placement platform 200. A drive gear 430 is mounted on the transmission shaft 420. The drive motor 410 is connected to the transmission shaft 420 via a timing belt mechanism. The drive gear 430 can mesh with the external drive gear of the metering pump placed on the metering pump placement platform 200. It will be appreciated that the upper surface of the metering pump placement platform 200 is provided with a groove that matches the shape of the metering pump housing to provide stable support for the metering pump. The height and angle of the metering pump placement platform 200 should be set according to the height of the drive gear 430 and the two liquid nozzles, so that the external drive gear of the metering pump placed on the metering pump placement platform 200 can just mesh with the drive gear 430, while the height of the liquid inlet and outlet of the metering pump is flush with the height of the two liquid nozzles.

[0026] Reference Figure 1 In this embodiment, three label printers 500 are further provided on the rack 100. The three label printers 500 are connected to the electronic control system of the test bench and are used to print labels of corresponding styles according to the test results and stick them on the metering pumps to avoid errors in manual label printing and resulting in errors in the classification of the metering pumps. The three label printers 500 correspond to different flow ranges. The electronic control system selects the corresponding label printer 500 to print the corresponding style of label according to the flow range into which the reading of the flow meter FT falls.

[0027] Reference Figure 2 and Figure 3 In this embodiment, the test platform 110 is provided with a waste liquid recovery funnel 112 below both the measuring cup placement position 111 and the metering pump placement platform 200. A support net is provided at the inlet of the waste liquid recovery funnel 112 to support the measuring cup and prevent foreign matter from falling into the waste liquid recovery funnel 112. The outlet of the waste liquid recovery funnel 112 is connected to a waste liquid tank to recover waste liquid leaked during the test.

[0028] Reference Figure 4 In this embodiment, a temperature sensor and a liquid level sensor are provided in the waste liquid tank. The temperature sensor is used to measure the temperature of the liquid in the waste liquid tank, and the liquid level sensor is used to detect the liquid level in the waste liquid tank to avoid insufficient test liquid in the waste liquid tank. An air conditioner is also provided on one side of the waste liquid tank to maintain a stable temperature of the liquid in the waste liquid tank to avoid changes in the liquid parameters due to temperature changes, which may affect the consistency of the test results. Figure 1 A display screen 130 is provided on the frame 100. The display screen 130 is electrically connected to the electronic control system of the test bench and can intuitively display the readings of the liquid level sensor, flow meter and temperature sensor.

[0029] Reference Figure 4 During the actual test process, in order to further improve the accuracy of the test results, it is necessary to first evacuate the air in the test liquid circuit and the metering pump. Therefore, in this embodiment, an emptying liquid circuit is also provided in the frame 100. The inlet and outlet of the emptying liquid circuit are both connected to the waste liquid tank. A liquid pump is connected in series to the emptying liquid circuit. The liquid inlet nozzle 350 is connected to the test liquid circuit and the emptying liquid circuit through the second control valve JA. The first control valve GA can be controlled to control the connection between the liquid inlet nozzle 350 and the emptying liquid circuit or the test liquid circuit. In this embodiment, the first control valve GA and the second control valve JA are both two-position four-way valves. The two input ends of the first control valve GA are respectively connected to the liquid outlet nozzle 340 and the second output end. One of the two output ends is blocked and discarded, and the other is connected to the second output end. The two input ends of the second control valve JA are respectively connected to the emptying liquid circuit and the test liquid circuit. One output end is blocked and discarded, and the other output end is connected to the liquid outlet nozzle 340. A first pressure gauge Y1 is installed between the second control valve JA and the liquid pump. A flow meter FT and a second pressure gauge Y2 are installed between the first control valve GA and the liquid outlet 340. A first relief valve X1 is also connected in series to the liquid drain path. A second relief valve X2 is also connected in series between the first control valve GA and the liquid outlet 340. The pressure gauge dials 140 for the first and second pressure gauges Y1 and Y2 are located on the front of the frame 100. The relief valve handles 150 for the first and second relief valves X1 and X2 are also located on the front of the frame 100 to facilitate pressure adjustment in the liquid path during draining. In this embodiment, the waste liquid tank contains test oil, so an oil filter is also installed in the liquid drain path to filter the test oil.

[0030] After the metering pump to be tested is clamped by the clamping mechanism 300, the first control valve GA is first located in the right position, and the second control valve JA is first located in the left position. The metering pump drive mechanism 400 and the liquid pump are both working to evacuate the air in the test liquid circuit and the metering pump. The pressure in the liquid circuits before and after the metering pump is adjusted to meet the test requirements by adjusting the handles of the two overflow valves; then the second control valve JA is located in the right position, the liquid pump is closed, and the metering pump directly draws liquid from the waste liquid tank, and the valve core position of the first control valve GA is adjusted according to the test mode. If it is a batch test mode, the valve core of the first control valve GA is kept in the right position, and the liquid pumped out by the metering pump flows back to the waste liquid tank; if it is a random inspection mode, the valve core of the first control valve GA is located in the left position, so that the liquid pumped out by the metering pump flows into the metering cup through the first output end 120.

[0031] It should be noted that in the description of the present invention, if there are any descriptions of directions, such as up, down, front, back, left, right, etc., the directions or positional relationships indicated are all based on the directions or positional relationships shown in the accompanying 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 direction, be constructed or operated in a specific direction, and cannot be understood as a limitation on the present invention.

[0032] In the description of this utility model, "several" means one or more, "more" means two or more, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. If there are descriptions of "first," "second," and so on, these are used solely to distinguish technical features and are not to be construed as indicating or implying relative importance, or implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0033] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0034] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A metering pump flow detection station, characterized in that: include: The frame (100) is provided with a horizontal test platform (110), and the test platform (110) is provided with a measuring cup placement position (111); A waste liquid tank, disposed in the frame (100) and used for containing liquid for testing; a test liquid circuit, arranged in the frame (100), with an input end connected to the waste liquid tank, a first output end (120) arranged above the measuring cup placement position (111), a second output end connected to the waste liquid tank, and a flow meter provided on the test liquid circuit; A metering pump placement table (200) is provided above the test platform (110) and is used to place a metering pump to be tested; A clamping mechanism (300) comprising a liquid inlet nozzle (350), a liquid outlet nozzle (340) and a clamping drive mechanism, wherein the liquid inlet nozzle (350) and the liquid outlet nozzle (340) are respectively arranged on both sides of the metering pump placement platform (200), and the clamping drive mechanism is used to adjust the distance between the liquid inlet nozzle (350) and the liquid outlet nozzle (340) so that the liquid inlet nozzle (350) is pressed against the liquid inlet of the metering pump to be tested, and the liquid outlet nozzle (340) is pressed against the liquid outlet of the metering pump to be tested, the liquid inlet nozzle (350) is connected to the test liquid path, and the liquid outlet nozzle (340) is connected to the first output end (120) and the second output end through a first control valve, and the liquid flowing through the metering pump to be tested is discharged from the first output end (120) into the measuring cup at the measuring cup placement position (111) or flows back from the second output end into the waste liquid tank by controlling the first control valve; The metering pump driving mechanism (400) is arranged on one side of the metering pump placement platform (200) and is used to drive the metering pump to be tested placed on the metering pump placement platform (200) to operate.

2. The metering pump flow detection station according to claim 1, characterized in that: The clamping drive mechanism includes a clamping motor (310), a clamping screw pair (322), a fixed bracket (320) and a movable bracket (330), wherein the fixed bracket (320) is fixedly arranged on the side of the metering pump placement table (200) facing away from the liquid inlet nozzle (350), the clamping screw pair (322) is horizontally arranged on the fixed bracket (320), and a plurality of guide rods (321) are arranged on the fixed bracket (320), the movable bracket (330) includes a guide block (332) and a liquid nozzle bracket (331), and the guide rods (321) are arranged on the fixed bracket (320). The block (332) is connected to the screw nut of the clamping screw pair (322), the guide block (332) is slidably connected to the guide rod (321) through a linear bearing, the guide block (332) is connected to the liquid nozzle bracket (331) through a connecting column (333), the liquid outlet nozzle (340) is arranged on the liquid nozzle connecting plate, and a plurality of elastic members (3311) are arranged between the liquid nozzle connecting plate and the liquid nozzle bracket (331), and the screw of the clamping screw pair (322) is drivingly connected to the output shaft of the clamping motor (310).

3. The metering pump flow detection station according to claim 2, characterized in that: A pressure sensor (3312) is provided between the liquid nozzle connecting plate and the liquid nozzle bracket (331).

4. The metering pump flow detection station according to claim 1, characterized in that: The metering pump driving mechanism (400) comprises a driving motor (410), a transmission shaft (420) and a driving gear (430); the transmission shaft (420) is rotatably arranged on one side of the metering pump placement platform (200); the transmission shaft (420) is in driving connection with the output shaft of the driving motor (410); the driving gear (430) is arranged on the transmission shaft (420); and the driving gear (430) can mesh with an external driving gear of a metering pump to be tested placed on the metering pump placement platform (200).

5. The metering pump flow detection station according to claim 1, characterized in that: A label printer (500) is provided on the frame (100), and the label printer (500) is used to print a label according to the test result of the metering pump.

6. The metering pump flow detection station according to claim 1, characterized in that: A temperature sensor and a liquid level sensor are arranged in the waste liquid tank.

7. The metering pump flow detection station according to claim 1, characterized in that: The test platform (110) is provided with a waste liquid recovery funnel (112) below the measuring cup placement position (111) and the metering pump placement platform (200), a support net is provided at the inlet of the waste liquid recovery funnel (112), and the outlet of the waste liquid recovery funnel (112) is connected to the waste liquid tank.

8. The metering pump flow detection station according to claim 1, characterized in that: The rack (100) is further provided with an emptying liquid circuit, the inlet and outlet of the emptying liquid circuit are both connected to the waste liquid tank, a liquid pump is connected in series to the emptying liquid circuit, the liquid inlet nozzle (350) is connected to the test liquid circuit and the emptying liquid circuit via a second control valve, and the liquid inlet nozzle (350) is connected to the test liquid circuit or the emptying liquid circuit by controlling the second control valve.

9. The metering pump flow detection station according to claim 8, characterized in that: A first pressure gauge is provided on the liquid draining path, and a second pressure gauge is provided between the liquid outlet nozzle (340) and the first control valve.

10. The metering pump flow detection station according to claim 9, characterized in that: A first overflow valve is provided on the liquid draining path, and a second overflow valve is provided between the liquid outlet nozzle (340) and the first control valve.

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