A pump core capable of back suction

Abstract

A back-suction pump core includes a pump shell assembly, a connecting rod, a piston rod, a piston, an elastic reset member and a steel ball. The piston rod and the connecting rod form a liquid outlet channel and are provided with a pushing part at the bottom. The piston is sleeved on the piston rod. The elastic reset member provides a reset force. The steel ball is arranged at the bottom of the liquid inlet of the pump shell assembly. When pressed, the connecting rod drives the piston rod and the piston to move downward. The pushing part and the piston form an initial interval to open the liquid outlet channel. When rebounding, the elastic reset member pushes the piston rod to move upward. The piston lags behind due to the liquid resistance to form a delayed sealing distance. The pump cavity generates negative pressure to suck the residual liquid. Then, the pushing part drives the piston to complete the sealing. The pump core optimizes the linkage structure of the piston rod and the piston, prolongs the rebound stroke to achieve delayed sealing, and combines the spring reset force with the atmospheric pressure to solve the problems of residual liquid pollution, dripping and inaccurate measurement in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of push pump technology, and in particular to a pump core with back suction capability. Background Technology

[0002] In the field of push-pump technology, the design of back-suction pump cores has always been a key research direction for preventing residue and dripping performance. Existing push-pump cores mainly drive liquid discharge through the pressing stroke, but they have significant shortcomings in back-suction function. Among them, the conventional spring return structure is the most common, but this type of structure has significant technical defects in practical applications.

[0003] Conventional spring-reset structures typically use a pressing connecting rod to move a piston rod, utilizing atmospheric pressure for liquid intake. However, during reset, they rely solely on spring force for rapid sealing, although some designs attempt to improve the back-suction design. For example, the "Top-plate Back-Suction Emulsion Pump" disclosed in Chinese Utility Model Patent Application No. 202120043463.1 (Authorization Announcement No. CN214987285U) achieves back-suction through a spring-loaded thin plate inside the cap. When pressed, the thin plate depresses to discharge liquid, and upon release, it elastically draws back residual liquid. However, this solution has drawbacks: firstly, the back-suction power depends on the elastic deformation of the thin plate, which can easily leave droplets when the liquid viscosity is high or the pressing stroke is insufficient; secondly, the planar sealing between the thin plate and the inlet hole is prone to failure due to fatigue or impurity accumulation, posing a risk of contamination in scenarios with high hygiene requirements.

[0004] In summary, the limitations of existing technologies lie in the fact that current back-suction designs do not establish a long-term mechanism of "stroke delay-air pressure coordination." For example, the aforementioned patent does not optimize the rebound stroke, but only generates instantaneous back-suction force through local deformation of the thin sheet, and cannot utilize the synergistic effect of atmospheric pressure and spring force like conventional pump cores; its sealing structure is an "instant seal," which quickly closes the flow channel after pressing stops, without setting a longer delayed sealing distance, causing liquid to continue to flow out due to inertia during the rebound process, especially when transporting viscous liquids, resulting in significant dripping problems.

[0005] Therefore, how to provide a pump core that can be drawn back by optimizing the piston rod and piston linkage structure to extend the rebound stroke to achieve delayed sealing, and combining the spring restoring force with the principle of atmospheric pressure, so as to solve the problems of residual liquid contamination, dripping and inaccurate metering in the existing technology, has become an urgent technical problem to be solved in the field of press pump technology. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a pump core that can be drawn back by optimizing the piston rod and piston linkage structure to extend the rebound stroke to achieve delayed sealing, and combining the synergistic effect of air pressure and spring force.

[0007] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: the reversible pump core includes...

[0008] The pump housing assembly has a liquid inlet at its bottom;

[0009] The connecting rod is located inside the pump housing assembly and moves up and down. Its upper end is exposed outside the pump housing assembly to connect to the external pressing component.

[0010] The piston rod is connected to the connecting rod and together they form a liquid outlet channel, and its bottom is provided with a radially protruding pushing part;

[0011] The piston is axially movably mounted on the piston rod and can move upward under the drive of the pusher.

[0012] An elastic reset element, with its two ends abutting against the piston rod and pump housing assembly respectively, provides an upward reset force to the piston rod; a steel ball is located at the liquid inlet at the bottom of the pump housing assembly to form a one-way valve structure; wherein...

[0013] When pressed, the connecting rod moves down, causing the piston rod to move down synchronously. The lower end of the connecting rod then pushes the piston down, opening the liquid outlet channel. At this time, an initial gap is formed between the pushing part and the piston.

[0014] In the rebound state, the elastic reset member pushes the piston rod upward. The piston moves upward with lag due to liquid resistance, forming a delayed sealing distance. Within this delayed sealing distance, a negative pressure is generated in the pump chamber and the residual liquid in the outlet channel is drawn back. Subsequently, the pushing part of the piston rod contacts and drives the piston upward to complete the sealing of the outlet channel.

[0015] To ensure precise transmission between the piston, piston rod, and connecting rod, and to prevent power transmission failure during pressing, preferably, the piston has an upwardly extending connecting portion and a downwardly extending abutting portion, the abutting portion abutting against the pushing portion of the piston rod;

[0016] The connecting rod is a hollow tube with an insertion wall formed on its bottom tube wall, the diameter of which is larger than that of the tube wall. The piston rod is inserted into the tube wall of the connecting rod, and the connecting part of the piston extends upward into the interior of the insertion wall. The lower end of the connecting rod can abut against the top surface of the piston to push the piston downward when pressed.

[0017] To enhance the axial fixation strength of the connecting rod and the piston rod and prevent them from loosening during reciprocating motion, preferably, a convex ring is formed on the tube wall of the connecting rod, and a groove adapted to the convex ring is formed at the corresponding position of the piston rod, and the convex ring and the groove are engaged with each other to complete the axial fixation of the connecting rod and the piston rod.

[0018] To optimize the channel structure of the liquid outlet and ensure smooth liquid flow, preferably, the piston rod has an axial hole extending vertically and a transverse through hole communicating with it. The axial hole, the transverse through hole, and the connecting rod together constitute the liquid outlet channel.

[0019] In order to achieve precise sealing of the liquid outlet channel and prevent backflow of liquid after back suction, preferably, a first groove is formed on the top of the piston rod pushing part for the lower edge of the piston abutment part to abut; when the lower edge of the abutment part abuts against the first groove, the inner wall of the abutment part seals both ends of the transverse through hole.

[0020] To fix the installation position of the compression spring and prevent the spring from shifting during the reset process, preferably, the elastic reset member is a compression spring, and the bottom of the piston rod push part is formed with a second groove for placing the upper end of the compression spring, and the groove wall of the second groove is formed with a plurality of circumferentially spaced fixing ribs for fixing the compression spring.

[0021] To improve the flow efficiency of liquid in the pump chamber and reduce flow resistance, preferably, the peripheral wall of the piston rod push part is provided with a plurality of through grooves arranged circumferentially to increase the flow rate of liquid from bottom to top.

[0022] To limit the piston's stroke and prevent excessive piston movement that could lead to structural failure, the pump housing assembly preferably includes a bayonet seat that is inserted into the top opening of the pump housing, and the connecting rod passes through the bayonet seat and protrudes from the top of the pump housing assembly.

[0023] The lower end of the bayonet seat constitutes the upper stroke limiting structure of the piston, and the pump housing is also provided with the lower stroke limiting structure of the piston.

[0024] To ensure the effectiveness of the delayed sealing distance and guarantee the negative pressure back suction effect, preferably, the axial length of the initial interval is 3 to 5 mm.

[0025] Compared with existing technologies, the advantages of this invention are as follows: By setting an axially movable piston and piston rod linkage structure within the pump housing assembly, an initial gap is formed between the piston rod's pushing part and the piston in the pressing state. In the rebound state, an elastic reset component drives the piston rod upward, while the piston lags behind due to liquid resistance, forming a delayed sealing distance. Because a negative pressure zone is continuously generated in the pump chamber within this delayed sealing distance, residual liquid in the outlet channel can be completely sucked back. Subsequently, the pushing part contacts and drives the piston upward, ultimately sealing the outlet channel. Compared to existing technologies that rely on a single rebound design using a spring-loaded sheet, this solution uses the spring's reset force and atmospheric pressure to collaboratively construct a long-lasting rebound mechanism. This not only provides stronger rebound power and higher stability, adapting to the transport of liquids of different viscosities, but also avoids inertial dripping of liquid, solving problems such as insufficient rebound power and sealing failure. Attached Figure Description

[0026] Figure 1 This is a three-dimensional structural diagram of this embodiment;

[0027] Figure 2 This is a three-dimensional exploded view of this embodiment;

[0028] Figure 3 This is a three-dimensional exploded view from another angle of this embodiment;

[0029] Figure 4 This is a cross-sectional view of this embodiment (in the pressed state);

[0030] Figure 5 This is a cross-sectional view of this embodiment (in the springback state). Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] Figures 1-5 The diagram shown is a schematic diagram of this embodiment. The backflowable pump core in this embodiment includes a pump housing assembly 1, a connecting rod 2, a piston rod 3, a piston 5, an elastic reset member 6, and steel balls 7, etc.

[0033] The structure and connection method of each component are described below.

[0034] Pump housing assembly 1: Refer to 1 to Figure 4 As shown, the pump housing assembly 1 includes a pump housing 1b and a bayonet seat 1c. The pump housing 1b is a hollow cylindrical structure with an inlet 1a at the bottom, where a steel ball 7 is placed to form a one-way valve structure. The bayonet seat 1c is inserted into the top opening of the pump housing 1b. The lower end of the bayonet seat 1c forms the upper stroke limiting structure 1d of the piston 5, and the pump housing 1b also has a lower stroke limiting structure 1e for the piston 5. A through hole is provided in the middle of the bayonet seat 1c for the connecting rod 2 to pass through.

[0035] Connecting rod 2: Refer to 2 to Figure 4 As shown, the connecting rod 2 is a hollow tube. Its upper end protrudes through the through hole of the bayonet seat 1c to the top of the pump housing assembly 1 for connecting to an external pressing component, and its lower end extends into the pump housing assembly 1. The bottom wall of the connecting rod 2 forms an insertion wall 2a with a diameter larger than the tube wall. A raised ring 2b is also provided on the tube wall for engaging and fixing with the groove 3b of the piston rod 3. The lower end of the connecting rod 2 can abut against the top surface of the piston 5, pushing the piston 5 downward when pressed.

[0036] Piston rod 3: Refer to 2 to Figure 4 As shown, the piston rod 3 is inserted into the tube wall of the connecting rod 2, forming a liquid outlet channel 4 together with the connecting rod 2. Its bottom has a radially protruding pushing part 3a, with a first groove 3e at the top and a second groove 3f at the bottom. Multiple circumferentially spaced through grooves 3g are provided on the peripheral wall of the pushing part 3a. The piston rod 3 has an axially extending hole 3c and a transverse through hole 3d, which, together with the hollow part of the connecting rod 2, constitute the liquid outlet channel 4. A raised ring 2b is formed on the tube wall of the connecting rod 2, and a corresponding groove 3b is formed on the piston rod 3 to fit the raised ring 2b. The raised ring 2b and the groove 3b are engaged to complete the axial fixation of the connecting rod 2 and the piston rod 3.

[0037] Piston 5: Piston 5 is sleeved on piston rod 3 and can move axially along piston rod 3. Piston 5 has an upwardly extending connecting portion 5a at its upper end and a downwardly extending abutting portion 5b at its lower end. The connecting portion 5a extends into the insertion wall 2a of the connecting rod 2, and the abutting portion 5b abuts against the first groove 3e of the pushing portion 3a. In the pressed state, the connecting rod 2 moves downward, causing the piston rod 3 to move downward synchronously. The lower end of the connecting rod 2 then pushes the piston 5 downward, opening the liquid outlet channel 4. At this time, an initial gap is formed between the pushing portion 3a and the piston 5. (Refer to...) Figure 4 As shown, the axial length A of the initial interval is 3-5 mm, and the optimal length is 3.7 mm.

[0038] Elastic reset element 6: Refer to 2 to Figure 4 As shown, the elastic reset member 6 is a compression spring. The upper end of the compression spring is placed in the second groove 3f at the bottom of the push part 3a. The groove wall of the second groove 3f is provided with circumferentially spaced fixing ribs 3f1 to fix the compression spring. The lower end of the compression spring abuts against the stepped surface inside the pump housing assembly 1 to provide an upward reset force for the piston rod 3.

[0039] The working principle of the backflow-capturing pump core in this embodiment is as follows:

[0040] 1. Pressing state

[0041] When pressing the external pressing part, refer to Figure 4As shown, the connecting rod 2 moves downward, and the piston rod 3 moves downward synchronously through the engagement of the convex ring 2b and the slot 3b. After the connecting rod 2 moves downward to the set position, the lower end of the connecting rod 2 abuts against the top surface of the piston 5, and begins to push the piston 5 downward. At this time, the abutting part 5b of the piston 5 separates from the first groove 3e of the pushing part 3a, the two ends of the transverse through hole 3d open, and the liquid outlet channel 4 is opened. An initial gap with an axial length A of 3.7mm is formed between the pushing part 3a and the piston 5. This dimension is optimized to ensure the balance between the change in pump chamber volume and the negative pressure back suction efficiency. At this time, the pump chamber volume decreases, the liquid is discharged through the liquid outlet channel 4, the steel ball 7 is pushed open, and the liquid enters the pump chamber from the liquid inlet 1a.

[0042] 2. Rebound state

[0043] After releasing the pressing part, refer to Figure 5 As shown, the compression spring releases its elastic potential energy, pushing the piston rod 3 upward. The piston 5 lags behind the piston rod 3 due to liquid resistance, creating a delayed sealing distance. This generates negative pressure within the pump chamber, driving the residual liquid in the outlet channel 4 back into the pump chamber. When the piston rod 3 moves upward to the set distance, the first groove 3e of the pushing part 3a contacts the abutment part 5b of the piston 5, causing the piston 5 to move upward. The inner wall of the abutment part 5b seals the transverse through hole 3d, completing the sealing of the outlet channel 4. The piston 5 stops when it reaches the upper stroke limiting structure 1d of the bayonet seat 1c, completing the back-suction process.

[0044] This embodiment optimizes the initial gap between the pusher 3a and the piston 5 to 3.7mm, and precisely controls the duration of negative pressure generation within the delayed sealing distance, which can significantly improve the back suction efficiency of high-viscosity liquids. It effectively solves the problems of residual liquid contamination, dripping and inaccurate measurement in the prior art, and is applicable to fields such as pharmaceuticals, high-precision measurement and high-end consumer products.

[0045] It should be noted that in the description of this embodiment, the terms "front," "rear," "left," "right," "inner," "outer," "upper," and "lower," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A back siphonable pump cartridge, comprising: include Pump housing assembly (1), with a liquid inlet (1a) at its bottom; The connecting rod (2) is located inside the pump housing assembly (1) and moves up and down. Its upper end is exposed outside the pump housing assembly (1) to connect to the external pressing component. The piston rod (3) is connected to the connecting rod (2) and together they form a liquid outlet channel (4), and its bottom is provided with a radially protruding pushing part (3a); The piston (5) is axially movably sleeved on the piston rod (3) and can move upward under the drive of the pusher (3a); The elastic reset member (6) abuts against the piston rod (3) and the pump housing assembly (1) at both ends to provide an upward reset force to the piston rod (3); A steel ball (7) is provided at the bottom inlet (1a) of the pump housing assembly (1) to form a one-way valve structure; in When pressed, the connecting rod (2) moves down and drives the piston rod (3) to move down synchronously. The lower end of the connecting rod (2) pushes the piston (5) down and opens the liquid outlet channel (4). At this time, an initial gap A is formed between the pushing part (3a) and the piston (5). In the rebound state, the elastic reset member (6) pushes the piston rod (3) to move upward, and the piston (5) moves upward with lag due to liquid resistance, forming a delayed sealing distance. Within this delayed sealing distance, negative pressure is generated in the pump chamber and the residual liquid in the liquid outlet channel (4) is sucked back. Then the pushing part (3a) of the piston rod (3) contacts and drives the piston (5) to move upward to complete the sealing of the liquid outlet channel (4).

2. The suction-removable pump core according to claim 1, characterized in that The piston (5) has an upwardly extending connecting portion (5a) and a downwardly extending abutting portion (5b), the abutting portion (5b) abutting against the pushing portion (3a) of the piston rod (3); The connecting rod (2) is a hollow tube, and an insertion wall (2a) with a diameter larger than the tube wall is formed on the bottom tube wall; The piston rod (3) is inserted into the tube wall of the connecting rod (2), and the connecting part (5a) of the piston (5) extends upward into the interior of the insertion wall (2a); The lower end of the connecting rod (2) can abut against the top surface of the piston (5) to push the piston (5) downward when pressed.

3. The suction-removable pump core according to claim 1, characterized in that: A convex ring (2b) is formed on the tube wall of the connecting rod (2), and a groove (3b) adapted to the convex ring (2b) is formed at the corresponding position of the piston rod (3). The convex ring (2b) and the groove (3b) are engaged with each other to complete the axial fixation of the connecting rod (2) and the piston rod (3).

4. The suction-removable pump core according to claim 1, characterized in that: The piston rod (3) has an axial hole (3c) extending vertically and a transverse through hole (3d) communicating with it. The axial hole (3c), the transverse through hole (3d) and the connecting rod (2) together constitute the liquid outlet channel (4).

5. The suction-removable pump core according to claim 4, characterized in that The top of the piston rod (3) push part (3a) has a first groove (3e) for the lower edge of the piston (5) abutting part (5b) to abut; When the lower edge of the abutting part (5b) abuts against the first groove (3e), the inner wall of the abutting part (5b) closes both ends of the transverse through hole (3d).

6. The backflow-capable pump core according to claim 1, characterized in that: The elastic reset member (6) is a compression spring. The bottom of the piston rod (3) push part (3a) has a second groove (3f) for placing the upper end of the compression spring, and a plurality of circumferentially spaced fixing ribs (3f1) for fixing the compression spring are formed on the groove wall of the second groove (3f).

7. The backflow-capable pump core according to claim 1, characterized in that: The piston rod (3) pusher (3a) has a plurality of through grooves (3g) arranged circumferentially to increase the flow rate of liquid from bottom to top.

8. The backflowable pump core according to any one of claims 1 to 7, characterized in that: The pump housing assembly (1) includes a bayonet seat (1c) that is inserted into the top opening of the pump housing (1b), and the connecting rod (2) passes through the bayonet seat (1c) and protrudes from the top of the pump housing assembly (1). The lower end of the bayonet seat (1c) forms the upper stroke limiting structure (1d) of the piston (5), and the pump housing (1b) is also provided with the lower stroke limiting structure (1e) of the piston (5).

9. The backflowable pump core according to claim 1, characterized in that: The axial length A of the initial interval is 3 to 5 mm.

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