A liquid storage bin, a drug sustained infusion device and a drug sustained infusion method

Abstract

The present application relates to a kind of liquid medicine storage device, especially a kind of liquid storage bin, drug sustained-release infusion device and drug sustained-release infusion method.A kind of liquid storage bin, including several spiral liquid storage tanks and liquid outlet hole, the liquid outlet hole is located at the center of the spiral liquid storage tank, the liquid outlet hole with the spiral liquid storage tank one-to-one correspondence, the spiral of the spiral liquid storage tank is equidistant spiral, the spiral liquid storage tank is used to store liquid, the liquid outlet hole is used to discharge liquid.The liquid storage bin provided by the present application stores liquid by spiral spiral liquid storage tank, greatly reduces the area of cross section, thereby reducing the requirement for driving precision, is small in size, low in cost, control is simpler.

Description

TECHNICAL FIELD

[0001] The present application relates to a drug solution storage device, in particular to a drug storage container, a drug delivery device and a drug delivery method. BACKGROUND

[0002] At present, many diseases need continuous, slow and micro-dose drug delivery, such as the widely used insulin delivery for diabetes treatment, and the delivery of chemotherapy drugs for tumor treatment. By using a drug delivery pump, continuous and stable drug treatment can be achieved compared to single drug injection, physiological indicators can be smoothly controlled, and the side effects of large doses in a short time can be greatly reduced. In addition, the impact on the user's life caused by multiple drug delivery can also be avoided.

[0003] For example, in the treatment of diabetes, especially for type I diabetes patients or type II diabetes patients who need continuous drug intervention treatment, continuous wearing of an insulin pump for treatment is a very mature clinical treatment method. The principle is to continuously infuse insulin subcutaneously by an insulin pump to simulate physiological secretion of insulin to meet physiological needs, so as to control the blood glucose level in the body to remain within a suitable range, thereby avoiding the occurrence of hyperglycemia and the numerous complications caused by diabetes.

[0004] The speed and precision of drug delivery have a decisive influence on the treatment effect, adverse reactions and user experience. The dose error caused by the precision of the drug delivery system may lead to insufficient treatment effect, physiological parameter disorder, and even serious adverse reactions caused by drug overdose, resulting in medical accidents. Therefore, the liquid delivery control and drug delivery precision of such drug delivery devices are the core of the core. To achieve slow release of a specific amount of drug at a specific speed, especially at a small dose, is often a great design challenge. Usually, very complex and precise system design, as well as precise mechanical structure and driving devices, will undoubtedly increase the complexity of the device, development cost and user cost.

[0005] For example, insulin pump, such drug delivery system, usually mainly includes drug liquid storage tank, drug infusion driving device, drug infusion pipeline, electronic control module, power supply, user interaction module, etc. The current storage tank is often designed as a syringe type structure (cylindrical), including a cylindrical hollow shell, often made of plastic material, which is pre-installed with the target drug, such as insulin, etc.; wherein a push rod is installed, the push rod is installed with a plastic head at the end inside the storage tank, which can extrude the drug to extrude the drug from the storage tank while being pushed; the other end of the push rod is often designed with a threaded structure, which can be directly or through a gear set and connected with the driving device; the core of the driving device is often a micro, precision motor, which can realize high-precision motion control, and then convert into precise infusion of drug liquid. There are also no motor driving devices, which often use elastic bodies such as springs, coil springs, or deformation of memory metals to drive the gear set and then push the push rod to achieve drug extrusion. When the drug is slowly extruded from the storage tank, it will be injected into the subcutaneous target site through the drug infusion pipeline. During the whole process, the electronic control module will calculate the drug infusion rate and drug amount according to the software settings and algorithms, and then control the drug slow-release driving device. The user interaction module is often used for user input of basic information and display of system information to the user.

[0006] It can be seen that the core of controlling the precision of drug infusion is the storage tank and the driving device. Currently, there are two commonly used concentrations of insulin preparations, U100 and U40. The insulin pump usually uses U100 insulin preparation, for example, which means that each 1 milliliter of insulin solution contains 100 units of insulin. The infusion rate of the insulin pump is at least 0.1 u / hr or 0.05 u / hr, and the latter often has a higher price. At a rate of 0.1 u / hr, the entire infusion system needs to support 1 uL / hr, i.e. to achieve precise control of 1 microliter per hour, and to distribute evenly within 1 hour for continuous infusion, with an error of less than 3%. If the rate is 0.05 u / hr, the entire infusion system needs to support 0.5 uL / hr, which achieves precise control of 0.5 microliters per hour.

[0007] V = πr 2 *l

[0008] Where V is the volume of drug output, r is the internal radius of the cylindrical storage tank, and l is the distance the push rod advances. Through formula conversion, the formula for the push rod advancing distance can be obtained:

[0009]

[0010] Assuming the inner diameter is 12mm, if the infusion of 1 microliter per hour is to be achieved, the driving device needs to achieve the motion accuracy of about 8.84 microns in 1 hour. This is often a very big challenge, so the insulin pump generally uses high-precision DC motor or stepper motor, and also needs to cooperate with precision reducer and encoder. For example, many manufacturers use Swiss motor, which is very expensive, and greatly increases the cost of insulin pump, limiting the promotion and use of insulin pump therapy.

[0011] In addition, the current insulin pump is single hormone infusion, if you want to achieve multi-hormone control infusion, it will greatly increase the volume of the device, and the need for double precision infusion driving device, which will greatly increase the cost.

[0012] The current technical problems are:

[0013] The current drug sustained-release infusion pump often uses a syringe type liquid storage bin (cylindrical), so in order to meet the drug sustained-release speed and control accuracy, precise driving control is needed, and the motion control accuracy needs to meet several microns per hour, which is often a great design challenge.

[0014] To achieve the above control accuracy, precise driving devices such as high-precision motors, precision gear sets, encoders, etc. are often needed, which often increases the structural complexity and volume of the driving device.

[0015] Because of the high motion control accuracy, there are high requirements for the devices used, such as motors. This also brings very high device cost, which increases the production cost and user cost of the product;

[0016] The driving device of the current traditional sustained-release infusion pump often needs to use one or more spiral push rods, and the push rod often needs to be longer than the length of the liquid storage bin, and space needs to be reserved for the push rod in the structure of the pump, which increases the volume of the overall driving device.

[0017] High complexity, high precision driving device also means high failure rate and high maintenance difficulty, which often greatly increases the user's use difficulty and use cost. SUMMARY

[0018] To solve the above problems, the present application provides a liquid storage bin with small volume, small cross section and reduced control accuracy, and the specific technical scheme is:

[0019] A liquid storage bin, comprising a plurality of spiral liquid storage grooves and liquid outlet holes, the liquid outlet holes are located at the center of the spiral liquid storage grooves, the liquid outlet holes correspond to the spiral liquid storage grooves one by one, the spiral of the spiral liquid storage groove is equidistant spiral, the spiral liquid storage groove is used for storing liquid, and the liquid outlet hole is used for discharging liquid.

[0020] A medicine slow-release infusion device comprises: the above-mentioned liquid storage bin; a base, wherein the liquid storage bin is fixed on the base; a sealing piston, wherein the sealing piston is movably inserted into the spiral liquid storage groove; a flexible push rod, wherein one end of the flexible push rod is connected with the sealing piston; a reel, wherein the reel is rotatably installed on the base, and the other end of the flexible push rod is wound on the reel; a driving wheel, wherein the driving wheel is connected with the flexible push rod, and is used for driving the flexible push rod to move, and the flexible push rod drives the sealing piston to move towards the liquid outlet hole; and a driving device, wherein the driving device is installed on the base, and is connected with the driving wheel, and the driving device is used for driving the driving wheel to rotate.

[0021] Preferably, a plurality of driving holes are arranged on the flexible push rod in an array, a plurality of driving teeth are arranged on the driving wheel in an annular array, the driving teeth are matched with the driving holes, the driving teeth are movably inserted into the driving holes, and the driving teeth are used for driving the flexible push rod to move through the driving holes.

[0022] Further, the flexible push rod is made of a metal plate or a plastic plate.

[0023] Preferably, the flexible push rod comprises a plurality of push rod blocks and a plurality of push rod shafts, the plurality of push rod blocks are sequentially hinged through the plurality of push rod shafts, the push rod blocks are provided with driving holes matched with the driving teeth, and one end of the push rod block is provided with a rotating groove, and the rotating groove enables the push rod block to bend in only one direction.

[0024] Preferably, the flexible push rod further comprises a connecting block, the connecting block is fixed on one end of the flexible push rod, the connecting block is provided with a connecting buckle or a connecting slot, the sealing piston is provided with a connecting slot or a connecting buckle, and the connecting buckle is inserted into the connecting slot.

[0025] Further, the flexible push rod further comprises a magnet, the magnet is fixed at the bottom of the connecting slot and the connecting buckle respectively, and is oppositely arranged, and is used for enabling the connecting buckle to be inserted into the connecting slot.

[0026] Preferably, when the spiral liquid storage groove is provided with two, the sealing piston, the flexible push rod, the driving wheel and the driving device are all provided with two, and the spiral liquid storage groove, the sealing piston, the flexible push rod, the driving wheel and the driving device are one-to-one corresponding.

[0027] Preferably, when the spiral liquid storage groove is provided with two, the sealing piston and the flexible push rod are both provided with two, and the spiral liquid storage groove, the flexible push rod and the sealing piston are one-to-one corresponding, and the driving wheel is slidably installed on the base, and is used for being connected with the two flexible push rods respectively.

[0028] A medicine slow-release infusion method, which uses a spiral liquid storage tank with small cross section to store liquid, and a flexible push rod to push a sealing piston inserted in the spiral liquid storage tank to quantitatively output liquid, and the flexible push rod is driven by a driving wheel and a driving device.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The spiral liquid storage tank is arranged in a spiral manner to store liquid, so that the cross section area is greatly reduced, and the requirement for driving precision is reduced, and the volume is small, the cost is low, and the control is simpler. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a structural schematic view of a liquid storage bin;

[0032] Figure 2 is a sectional view of a liquid storage bin;

[0033] Figure 3 is a structural schematic view of a liquid storage bin provided with two spiral liquid storage tanks;

[0034] Figure 4 is a sectional view of a liquid storage bin provided with two spiral liquid storage tanks;

[0035] Figure 5 is a structural schematic view of a medicine slow-release infusion device;

[0036] Figure 6 is a structural schematic view of a flexible push rod;

[0037] Figure 7 is a structural schematic view of a flexible push rod bending;

[0038] Figure 8 is an exploded schematic view of a flexible push rod connected with a sealing piston through a connecting block;

[0039] Figure 9 is a schematic view of a flexible push rod connected with a sealing piston through a connecting block;

[0040] Figure 10 is a structural schematic view of example three;

[0041] Figure 11 is a structural schematic view of example four, and a driving wheel is located at one of the flexible push rods;

[0042] Figure 12 is a schematic view of a driving wheel located at another flexible push rod in example four. DETAILED DESCRIPTION

[0043] The present application will be further described with reference to the accompanying drawings.

[0044] Embodiment One

[0045] The liquid storage bin 1 has a spiral rotating liquid storage tank, which can greatly reduce the cross-sectional area of the liquid storage tank while fully utilizing the volume of the liquid storage bin 1, thereby significantly reducing the requirement for the movement precision of the liquid slow-release infusion pump driving device. In addition, the rotating structure can greatly shorten the volume occupied by the push rod in the traditional pump driving device, thereby reducing the volume of the overall driving device, and is more suitable for the demand of modern miniaturized pumps.

[0046] Specifically, as shown in Figure 1 and Figure 2 , a liquid storage bin includes a spiral liquid storage tank 11 and a liquid outlet hole 12, the liquid outlet hole 12 is located at the center of the spiral liquid storage tank 11, the liquid outlet hole 12 corresponds to the spiral liquid storage tank 11 one by one, the spiral of the spiral liquid storage tank 11 is equidistant spiral, the spiral liquid storage tank 11 is used for storing liquid medicine, and the liquid outlet hole 12 is used for discharging liquid.

[0047] Compared with the traditional syringe type liquid storage cavity, the embodiment greatly reduces the cross-sectional area of the liquid storage cavity and the push rod. For example, compared with the currently used cylindrical liquid storage cavity with an internal diameter of 12mm, the cross-sectional area of the liquid storage cavity is about 113.1mm 2 , and the cross-sectional area of the spiral liquid storage tank 11 is 6mm 2 , which is only 5.3% of the cross-sectional area of the existing liquid storage cavity. The cross-sectional area is greatly reduced, and the distance that the infusion push rod needs to advance for the same volume of medicine is 18.85 times that of the existing one. For the driving screw and motor, the movement precision of the embodiment can be reduced to 1 / 18.85 of the previous precision requirement. By adjusting the shape and size of the cross section, the cross-sectional area can be further reduced, thereby further reducing the precision requirement of the driving device. This is a big difference, more cost-effective motors can be considered and used, which can greatly reduce the cost. At the same time, the reduction of movement precision can greatly reduce the complexity and number of devices of the driving device, thereby reducing the cost and improving the stability of the system.

[0048] The liquid outlet hole 12 can be connected to the drug slow-release pipeline 13 through a threaded joint or a luer joint 14 or directly sleeved.

[0049] The liquid storage bin 1 can be made of medical grade plastics commonly used in medical devices, such as PP, PVC and other materials, and can be manufactured by mold injection, ultrasonic welding, gluing and other processes to form equidistant spiral liquid storage tanks 11 for storing liquid medicine, hormones and other liquids.

[0050] Embodiment Two

[0051] The liquid storage bin 1 can be expanded to store two or more drugs. Figure 3 and Figure 4 As shown, a double helix rotating structure is adopted to obtain two helix liquid storage grooves 11, realizing the isolated storage of two drugs, and two liquid outlet holes 12 are also provided, respectively located at the centers of the two helix liquid storage grooves 11, and the helix liquid storage grooves 11 correspond to the liquid outlet holes 12 one by one.

[0052] More helix liquid storage grooves 11 can also be provided according to needs.

[0053] Example Three

[0054] Based on the above-mentioned example one, as shown in Figure 5 and Figure 6 A drug slow-release infusion device includes a liquid storage bin, a base, a sealing piston 2, a flexible push rod 3, a reel 5, a driving wheel 4 and a driving device. The liquid storage bin 1 is fixed on the base, the reel 5 is rotatably installed on the base and located at one side of the liquid storage bin 1; the sealing piston 2 is movably inserted into the helix liquid storage groove 11; one end of the flexible push rod 3 is connected with the sealing piston 2, and the other end of the flexible push rod 3 is wound on the reel 5; the driving wheel 4 is connected with the flexible push rod 3 for pushing the flexible push rod 3 to move, and the flexible push rod 3 pushes the sealing piston 2 to move towards the liquid outlet hole 12; the driving device is installed on the base and connected with the driving wheel 4 for driving the driving wheel 4 to rotate.

[0055] The sealing piston 2 is inserted from the opening of the helix liquid storage groove 11, and the sealing piston 2 can be made of non-toxic and harmless medical rubber.

[0056] The flexible push rod 3 extrudes and pushes the sealing piston 2 to move along the helix liquid storage groove 11, thereby extruding the liquid in the helix liquid storage groove 11 to make the liquid extrude from the liquid outlet hole 12. The unused flexible push rod 3 is in a wound state, and as the drug is slowly infused, the wound flexible push rod 3 is stretched out by the driving wheel 4 and pushed into the helix liquid storage groove 11, thereby pushing the sealing piston 2 to move forward and extruding the drug.

[0057] The flexible push rod 3 can be made of a metal plate or a plastic plate, such as a stainless steel plate, a titanium alloy plate, a nickel alloy plate, etc. The thickness of the plate is less than the width of the helix liquid storage groove 11, and the plate has a certain flexibility and rigidity, which can bend along the helix liquid storage groove 11 and also push the sealing piston 2 to move. As shown in Figure 6 and Figure 7As shown, the flexible push rod 3 possesses good mechanical strength and rigidity in the X and Y axes, and good toughness and flexibility in the Z axis direction. Under certain stress conditions, it can deflect and bend to a certain extent in the Z axis direction. The flexible push rod 3 has an array of drive holes 31, and the drive wheel 4 has an annular array of drive teeth 41. The drive teeth 41 match the drive holes 31 and are movably inserted into them. The drive teeth 41 mesh with the drive holes 31, allowing the flexible push rod 3 to advance or retract along the X-axis direction via the drive teeth 41 and the drive holes 31.

[0058] Driven by the drive wheel 4, the flexible push rod 3 unfolds from its preset coiled shape and enters the spiral liquid storage tank 11, pushing the sealed piston 2 towards the liquid outlet 12. The flexible push rod 3 bends along the Z-axis direction with the spiral liquid storage tank 11, and as it gradually goes deeper, the flexible push rod 3 coils up inside the spiral liquid storage tank 11. Since both ends of the flexible push rod 3 are in a coiled state, the volume it occupies is greatly reduced.

[0059] like Figure 6 The diagram shows a flexible push rod 3 with one end curled 180° towards the Z-axis at a certain radius.

[0060] Example 4

[0061] like Figure 7 and Figure 8 As shown, to facilitate connection with the sealing piston 2, a connecting block 7 and a magnet 73 are also included. The connecting block 7 is fixed to one end of the flexible push rod 3, and a connecting buckle 71 is provided on the connecting block 7. The sealing piston 2 is provided with a connecting groove 72, and the connecting buckle 72 is inserted into the connecting groove 72. The magnet 73 is fixed to the bottom of the connecting groove 72 and the connecting buckle 71 respectively, and is arranged opposite to each other, for inserting the connecting buckle 71 into the connecting groove 72.

[0062] When the connecting block 7 approaches the sealing piston 2, the connecting block 7 will be attracted together by the attraction of the two magnets 73, so that the connecting buckle 71 is inserted into the connecting slot 72, achieving a positional alignment and a stable connection.

[0063] Example 5

[0064] The difference between this embodiment and embodiment three is that, as Figure 9 As shown, the flexible push rod 3 includes several push rod blocks 32 and push rod shafts 33. The several push rod blocks 32 are hinged in sequence through several push rod shafts 33. The push rod blocks 32 are provided with drive holes 31. One end of the push rod blocks 32 is provided with a rotating groove 34. The rotating groove 34 allows the push rod blocks 32 to bend in only one direction.

[0065] The push rod block 32 and the push rod shaft 33 make the flexible push rod 3 form a chain structure and can only bend in one direction, so that the Z-axis has a certain stiffness and can be pushed by the driving wheel 4.

[0066] In order to ensure reliable pushing, guide plates can also be installed on both sides of the flexible push rod 3, adjacent to the inlet of the spiral liquid storage tank 11, so that the flexible push rod 3 is always located in the tank, enabling the flexible push rod 3 to push the sealing piston 2 to move, avoiding the bending of the chain-type flexible push rod 3 during work.

[0067] Embodiment six

[0068] On the basis of any of the above embodiments, as Figure 10 indicated, it can be extended to an independent double-drug sustained infusion, the liquid storage bin 1 is provided with two spiral liquid storage tanks 11, two sealing pistons 2 are respectively installed in the two spiral liquid storage tanks 11, and the flexible push rod 3, the driving wheel 4 and the driving device are all provided with two. The spiral liquid storage tank 11, the sealing piston 2, the flexible push rod 3, the driving wheel 4 and the driving device correspond one by one.

[0069] Embodiment seven

[0070] The difference between this embodiment and embodiment six is that only one driving wheel 4 is provided, as Figure 11 and Figure 12 indicated, when the spiral liquid storage tank 11 is provided with two, the sealing piston 2 and the flexible push rod 3 are both provided with two, and the spiral liquid storage tank 11, the flexible push rod 3 and the sealing piston 2 correspond one by one, the driving wheel 4 is slidingly installed on the base and used for being connected with the two flexible push rods 3 respectively. The distance between the two flexible push rods 3 is greater than the outer diameter of the driving wheel 4, the driving wheel 4 can only be in contact with one of the flexible push rods 3 by moving the driving wheel 4, so as to realize the control of the two flexible push rods 3 respectively.

[0071] Embodiment eight

[0072] A drug sustained infusion method, using a spiral liquid storage tank 11 with a small cross section to store liquid, a flexible push rod 3 to push a sealing piston 2 movably inserted in the spiral liquid storage tank 11 to quantitatively output liquid, and the flexible push rod 3 being driven by a driving wheel 4 and a driving device.

[0073] A liquid storage bin with several spiral liquid storage tanks 11 can make full use of the volume of the liquid storage bin 1 while greatly reducing the cross-sectional area of the liquid storage bin 1, thereby reducing the precision requirement of the driving device for driving the liquid sustained infusion, and further reducing the complexity and the number of components of the driving device, avoiding the use of precise driving devices such as high-precision motors, precise gear sets and encoders, which not only reduces the overall size, improves the stability of the system and reduces the difficulty of equipment maintenance.

[0074] The rotary structure of the spiral liquid storage tank 11 can greatly shorten the volume occupied by the push rod in the conventional pump driving device, thereby reducing the volume of the overall driving device, and is more suitable for the demand of modern miniaturized pumps.

[0075] It is easy to expand to double-drug or multi-drug storage and driving.

[0076] The technical principles of the present application are described above in combination with specific embodiments. These descriptions are only for the purpose of explaining the principles of the present application and cannot be interpreted in any way as a limitation on the scope of protection of the present application. Based on the explanations herein, other specific embodiments of the present application can be conceived by those skilled in the art without creative labor, and these embodiments will fall within the scope of protection of the claims of the present application.

Claims

1. A drug sustained-release infusion device, characterized in that, include: The liquid storage tank includes several spiral liquid storage tanks (11) and liquid outlet holes (12). The liquid outlet holes (12) are located at the center of the spiral liquid storage tanks (11). The liquid outlet holes (12) correspond one-to-one with the spiral liquid storage tanks (11). The spiral of the spiral liquid storage tanks (11) is an equidistant spiral. The spiral liquid storage tanks (11) are used for storing liquid, and the liquid outlet holes (12) are used for discharging liquid. The spiral storage tank (11) and the outlet hole (12) are each provided in at least two forms for the isolated storage of drugs; The base, the liquid storage tank (1) is fixed on the base; A sealing piston (2) is movably inserted into the spiral liquid storage tank (11); A flexible push rod (3), one end of which is connected to the sealing piston (2); A reel (5) is rotatably mounted on the base, and the other end of the flexible push rod (3) is wound around the reel (5); A drive wheel (4) is connected to the flexible push rod (3) for pushing the flexible push rod (3) to move, and the flexible push rod (3) pushes the sealing piston (2) toward the liquid outlet (12); and A driving device is mounted on the base and connected to the driving wheel (4). The driving device is used to drive the driving wheel (4) to rotate.

2. The drug sustained-release infusion device according to claim 1, characterized in that, The flexible push rod (3) is provided with a plurality of drive holes (31) in an array, and the drive wheel (4) is provided with a plurality of drive teeth (41) in an annular array. The drive teeth (41) are matched with the drive holes (31), and the drive teeth (41) are movably inserted into the drive holes (31). The drive teeth (41) are used to push the flexible push rod (3) to move through the drive holes (31).

3. The drug sustained-release infusion device according to claim 2, characterized in that, The flexible push rod (3) is made of a metal plate or a plastic plate.

4. The drug sustained-release infusion device according to claim 2, characterized in that, The flexible push rod (3) includes several push rod blocks (32) and push rod shafts (33). The several push rod blocks (32) are hinged in sequence through the several push rod shafts (33). The push rod blocks (32) are provided with drive holes (31). One end of the push rod blocks (32) is provided with a rotating groove (34). The rotating groove (34) allows the push rod blocks (32) to bend in only one direction.

5. The drug sustained-release infusion device according to claim 1, characterized in that, It also includes a connecting block (7), which is fixed to one end of the flexible push rod (3). The connecting block (7) is provided with a connecting buckle and the sealing piston (2) is provided with a connecting groove, or the connecting block (7) is provided with a connecting groove and the sealing piston (2) is provided with a connecting buckle, and the connecting buckle is inserted into the connecting groove.

6. The drug sustained-release infusion device according to claim 5, characterized in that, It also includes a magnet (73), which is fixed to the bottom of the connecting slot and the connecting buckle respectively and is arranged opposite to each other, for inserting the connecting buckle into the connecting slot.

7. A drug sustained-release infusion device according to any one of claims 1 to 6, characterized in that, Two spiral liquid storage tanks (11) are provided, and two sealing pistons (2), flexible push rods (3), drive wheels (4) and drive devices are provided, and the spiral liquid storage tanks (11), sealing pistons (2), flexible push rods (3), drive wheels (4) and drive devices correspond one to one.

8. A drug sustained-release infusion device according to any one of claims 1 to 6, characterized in that, Two spiral liquid storage tanks (11) are provided, two sealing pistons (2) and two flexible push rods (3) are provided, and the spiral liquid storage tanks (11), flexible push rods (3) and sealing pistons (2) correspond one to one. The drive wheel (4) is slidably installed on the base and is used to connect to the two flexible push rods (3) respectively.

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