CN218113613U - Pump core mechanism and pressing pump comprising same - Google Patents

Abstract

A pump core mechanism is arranged in a pressing pump and comprises a piston head and a piston sleeved on the piston head. The piston head includes a cylindrical portion and a skirt portion extending from an outer surface of the cylindrical portion and extending downwardly to form a sandwich between the cylindrical portion and the skirt portion. The piston comprises an outer ring and an inner ring which are connected with each other, when the piston is sleeved on the piston head, the inner ring is inserted into the interlayer, and the piston can move up and down relative to the piston head, so that the inner ring moves up and down in the interlayer. The piston is characterized in that the skirt portion is provided with a first sealing surface, the inner ring is provided with a second sealing surface, and the first sealing surface and the second sealing surface are always matched to form sealing in the range between the stroke top dead center and the stroke bottom dead center of the piston relative to the piston head. The pump core mechanism with the structure can ensure that the dimensional deviation in the manufacturing process has no influence or little influence on the function of the pressing pump, thereby improving the stability of the function of the pressing pump. Still relate to a press pump including this pump core mechanism.

Description

Pump core mechanism and pressing pump comprising same

Technical Field

The present invention relates to a push pump for dispensing a product, and more particularly to the design of a pump cartridge structure in the push pump.

Background

Push-on pumps are widely used in the packaging of many products, such as household chemicals, washing chemicals, food and beverage products, pharmaceuticals, etc., for dispensing the product from a container for use by a user. The push pump can be used to dispense flowable, semi-flowable products, which has the advantages of convenience of use, dosing, and the like.

The core component of the push pump is the pump core, which is usually a plastic part. In use, it has been found that plastic pump core parts suffer from problems, for example, the dimensions of the plastic parts are susceptible to changes in ambient temperature, the forming process, die wear, and the like. Such dimensional changes of the pump core parts can cause unstable functions of the pump core, thereby causing problems of leakage in the pressing pump, reduced pumping capacity due to weakened suction force of the pressing pump, increased times of air pressure in the using process, liquid leakage at the shaft center, no liquid discharge and the like.

The conventional means for solving the problem of dimensional change of pump core parts by the existing manufacturers mainly comprises improving the precision of a mold, strengthening the monitoring of a part forming process, improving the detection rate of products and the like so as to improve the dimensional stability of the plastic parts of the pump core. However, these measures significantly increase the process complexity in the manufacturing process of the press pump, and further increase the manufacturing cost of the press pump. On the other hand, the improvement of the dimensional stability of the pump core parts by the means is limited, and the size fluctuation of the parts in the manufacturing process cannot be completely avoided.

Therefore, in the existing manufacturing process of the pressing pump, the problem of unstable pumping function of the pressing pump caused by the size change of the plastic parts of the pump core is not fundamentally solved.

Thus, in the field of press pump manufacturing, there is a need for improvement of the structure of each part in the press pump, particularly the pump core mechanism thereof, to solve the above-described problems in the prior art.

SUMMERY OF THE UTILITY MODEL

The present invention is made in order to solve the above-mentioned problems existing in the prior art. The utility model aims at providing a pump core mechanism with improve structure, it can make according to the size deviation that the pump can not influence its pumping function because of the pump core part.

The utility model discloses a pump core mechanism is arranged in setting up according to the pressure pump, and this pump core mechanism includes that piston head and cover establish the piston on the piston head. The piston head includes a cylindrical portion and a skirt portion extending from an outer surface of the cylindrical portion and extending downwardly to form a sandwich between the cylindrical portion and the skirt portion. The piston comprises an outer ring and an inner ring which are connected with each other, when the piston is sleeved on the piston head, the inner ring is inserted into the interlayer, and the piston can move up and down relative to the piston head, so that the inner ring moves up and down in the interlayer. Wherein the skirt portion is provided with a first sealing surface, the inner ring is provided with a second sealing surface, and wherein, in the range between the stroke top dead center and the stroke bottom dead center of the piston relative to the piston head, the first sealing surface and the second sealing surface are always matched to form sealing.

In the above pump core mechanism including the piston head and the piston, the skirt portion is formed on the piston head, and the seal between the piston head and the piston is formed by the cooperation of the skirt portion of the piston head and the inner ring of the piston. The structure has low requirement on manufacturing precision, and even if the deviation in size exists in the manufacturing process, the function of the finally manufactured pressing pump is not influenced or is slightly influenced, so that the stability of the function of the pressing pump can be improved, the requirement on manufacturing is reduced, and the manufacturing cost can be reduced.

In addition, the piston head, and in particular the cylindrical portion thereof, typically needs to be made of a material having a greater hardness, but the skirt portion on the piston head may be made of a material different from that of the cylindrical portion, such as a material having a lower coefficient of friction with the inner ring of the piston. In this way, the corresponding sensitivity of the one-way valve formed by the piston and the bore in the piston head is increased, i.e. the one-way valve can open immediately when pressed down and close quickly when the pressure is removed.

In one particular arrangement, the first sealing surface is formed on an inner surface of the skirt and the second sealing surface is formed on an outer surface of the inner ring, wherein one of the first and second sealing surfaces has an annular convex surface formed thereon that sealingly engages the other of the first and second sealing surfaces.

Preferably, an annular convex surface is formed on an upper portion of the second sealing surface. Alternatively, an annular convex surface is formed on a lower portion of the first sealing surface.

The annular convex surface helps to form an effective dynamic seal between the piston head and the piston and also reduces frictional resistance between the piston head and the piston as they move relative to one another.

In one exemplary structure, the piston further includes a web connecting the outer ring and the inner ring, the web dividing the inner ring into an upper inner ring and a lower inner ring, and at least one of the following seal surfaces is formed in the pump core mechanism:

a third sealing surface disposed on an upper portion of the first sealing surface and facing inward, wherein the upper portion of the second sealing surface is in sealing contact with the third sealing surface when the piston moves relative to the piston head to a top dead center of travel;

the fourth sealing surface is formed at the position where the upper inner ring is connected with the web plate, and when the piston moves to a stroke top dead center relative to the piston head, the lower part of the first sealing surface is in sealing contact with the fourth sealing surface; and

and a fifth sealing surface formed on the upper portion of the skirt portion and facing outward, wherein the upper portion of the second sealing surface is in sealing contact with the fifth sealing surface when the piston moves to the top dead center of the stroke relative to the piston head.

Here, the provision of the third to fifth sealing surfaces may help to further improve the seal between the piston head and the piston.

Preferably, at least one of the third, fourth and fifth sealing surfaces is a bevel, a sphere, or a combination of bevel and sphere.

Further, the piston head also comprises a head part connected below the column part, wherein an opening for communicating the inside and the outside of the piston head is formed between the column part and the head part, and the opening is matched with the inner ring of the piston to form a one-way valve.

Preferably, a first step part is formed on the head part, a second step part is formed on the lower part of the inner ring of the piston, and when the piston moves to a stroke bottom dead center relative to the piston head, the first step part is in contact with the second step part to prevent the piston from moving downwards relative to the piston head. The first and second steps are provided to prevent the piston from being withdrawn from the piston head.

Preferably, the inner diameter of the inner ring is larger than the outer diameters of the columnar part and the head part. Thus, there is substantially no frictional resistance between the inner race and the cylindrical portion and head portion as the piston moves relative to the piston head.

Preferably, the outer diameter of the columnar portion is larger than the outer diameter of the head portion. Such an arrangement facilitates, on the one hand, the ease of demolding during manufacture of the piston head and, on the other hand, the ease of mounting the piston head and piston together.

The pressing pump comprises a pressing head and a tooth socket, wherein the pressing head can move in the up-and-down direction relative to the tooth socket, and a piston rod is arranged below the pressing head. Wherein, the pump core mechanism is arranged on the piston rod.

Drawings

The embodiments of the invention will become more apparent from the structure illustrated in the accompanying drawings, in which:

fig. 1a shows a cross-sectional view of the press pump of the present invention, wherein the press pump is in a standby state.

Fig. 1b shows another cross-sectional view of the push pump of the present invention, wherein the push pump is in a pushed state.

Figure 2a shows a cross-sectional view of the piston head of a first embodiment of the core mechanism of the invention.

Figure 2b shows a perspective view of the piston head of figure 2 a.

Fig. 3a shows a cross-sectional view of the piston of the pump core mechanism of the first embodiment of the present invention.

Fig. 3b shows a perspective view of the piston of fig. 3 a.

Fig. 4a shows a cross-sectional view of an assembled pump core mechanism of a first embodiment of the invention, with the piston in its position relative to bottom dead center of travel of the piston head.

Figure 4b shows another cross-sectional view of the assembled pump core mechanism of the first embodiment of the present invention with the piston in its top dead centre position relative to the piston head.

Figure 5 shows a cross-sectional view of a ram with a piston rod and a piston head to be mounted on the piston rod.

Fig. 6a shows a cross-sectional view of a second embodiment of the pump core mechanism of the present invention, wherein the piston is in its position relative to bottom dead center of travel of the piston head.

Figure 6b shows another cross-sectional view of the assembled pump core mechanism of the second embodiment of the present invention with the piston in its top dead centre position relative to the piston head.

Fig. 7a shows a cross-sectional view of a third embodiment of the pump core mechanism of the present invention, where the piston is at its position relative to bottom dead center of travel of the piston head.

Figure 7b shows another cross-sectional view of the third embodiment of the invention assembled pump core mechanism with the piston in its top dead centre position relative to the piston head.

Fig. 8a shows a cross-sectional view of a pump core mechanism of a fourth embodiment of the present invention, where the piston is at its position relative to bottom dead center of travel of the piston head.

Fig. 8b shows another cross-sectional view of the assembled pump core mechanism of the fourth embodiment of the present invention with the piston in its position relative to the top dead center of travel of the piston head.

Detailed Description

In order to facilitate understanding of the present invention, the following description will be made in detail of a pump according to the present invention, and particularly, a pump core mechanism thereof, with reference to the accompanying drawings. It is understood that the drawings depict only preferred embodiments of the invention and are not intended to limit the scope of the invention. Various obvious modifications, variations and equivalents of the present invention can be made by those skilled in the art on the basis of the embodiments shown in the drawings, and the technical features in the different embodiments described below can be arbitrarily combined with each other without contradiction, and these are within the scope of the present invention.

In the following detailed description of the present invention, terms indicating directions and orientations such as "upper", "lower", "inside", "outside", and the like are used with reference to the general orientation of the pressing pump shown in the drawings in a use state, and it is understood that the orientation of the pressing pump may be changed in cases such as transportation, storage, and the like.

< first embodiment >

Fig. 1a to 5 show a preferred structure of the first embodiment of the present invention. In which fig. 1a and 1b show a sectional view of the pressing pump 100 in a standby state and a pressed-down state, respectively.

The pressing pump 100 includes a pressing head 110 and a mouthpiece 120, and the pressing head 110 is movable in an up-and-down direction with respect to the mouthpiece 120. Ram 110 is provided with a piston rod 130. For example, piston rod 130 may be attached to the lower portion of ram 110, or piston rod 130 may be integrally formed on the lower portion of ram 110.

The pump core mechanism 140 of the push pump 100 is connected to the lower end of the piston rod 130. As shown, the core mechanism 140 includes a piston head 150 and a piston 160, wherein the piston 160 can be disposed outside the piston head 150 to form the core mechanism 140.

Figures 2a and 2b show a cross-sectional view and a perspective view, respectively, of the piston head 150, wherein the structure of the piston head 150 is more clearly shown. The piston head 150 includes a cylindrical portion 151 and a skirt portion 152, and the skirt portion 152 extends from an outer surface of the cylindrical portion 151 and extends downward, forming an interlayer 153 that opens downward between the cylindrical portion 151 and the skirt portion 152.

The piston head 150 further includes a head portion 154, the head portion 154 being connected below the cylindrical portion 151, and an opening 157 being formed between the cylindrical portion 151 and the head portion 154. The opening 157 communicates between the exterior and interior of the piston head 150 and cooperates with the inner race 162 of the piston 160 to form a one-way valve, as will be described in greater detail below.

The piston head 150 provided with the skirt 152 is particularly advantageous for the one-way valve described above. Specifically, the cylindrical portion 151 of the piston head 150 needs to be made of a harder material, such as a PP (polypropylene) material, while the skirt portion 152 may be made of a softer material, such as a PE (polyethylene) material, as with the piston 160. When assembled together, the inner race 162 of the piston 160 does not have to contact the outer surface of the cylindrical portion 151, but rather the skirt portion 152, which reduces frictional resistance between the piston head 150 and the piston 160, thereby improving the sensitivity of the check valve.

Fig. 3a and 3b show a cross-sectional view and a perspective view, respectively, of the piston 160 to more clearly show the structure of the piston 160. The piston 160 includes an outer race 161 and an inner race 162 that are coupled together. The outer ring 161 can be interference-fitted with a cylinder wall of the pressing pump 100, as in the case of the existing pressing pump, and is not described in detail herein. The inner race 162 is configured to fit over the piston head 150, thereby mounting the piston 160 to the piston head 150, and the piston head 150 and the piston 160 are movable in an up-and-down direction relative to each other. The inner ring 162 of the piston 160 is inserted in the sandwich layer 153, and the inner ring 162 moves in the sandwich layer 153 when the piston 160 moves in the up-down direction with respect to the piston head 150.

Fig. 4a and 4b show cross-sectional views of the piston head 150 and the piston 160 mounted together, where fig. 4a shows the piston 160 in its bottom-dead-center position of travel relative to the piston head 150, and fig. 4b shows the piston 160 in its top-dead-center position of travel relative to the piston head 150. Wherein the inner surface of the skirt portion 152 of the piston head 150, i.e. the surface facing the inner ring 162 of the piston 160, constitutes a first sealing surface 155 and the outer surface of the inner ring 162 of the piston 160 constitutes a second sealing surface 163. The first sealing surface 155 and the second sealing surface 163 cooperate to form a seal between the piston head 150 and the piston 160. Also, as can be seen, the skirt 152 and inner race 162 are configured and dimensioned such that, in the range between top-dead-center travel and bottom-dead-center travel of the piston 160 relative to the piston head 150, the first and second sealing surfaces 155, 163 always cooperate to form a seal, i.e., the seal between the piston head 150 and the piston 160 is always present.

Preferably, an annular convex surface is formed on one of the first and second sealing surfaces 155, 163 that sealingly engages the other of the first and second sealing surfaces 155, 163 to form a more effective dynamic seal. Moreover, the provision of the annular convex surface also facilitates reducing frictional resistance between the piston head 150 and the piston 160 as the piston 160 and the piston head 150 move in an up-and-down direction relative to each other. For example, in the exemplary construction shown in fig. 4a and 4b, an annular convex surface 164 is formed on an upper portion of inner race 162, preferably on the top of inner race 162. In this way, the piston 160 remains sealed at its bottom dead center of travel relative to the piston head 150, i.e., when only the upper portion of the second sealing surface 163 of the inner ring 162 contacts the first sealing surface 155 on the skirt 152, thereby ensuring that the seal between the piston head 150 and the piston 160 is always present.

Preferably, as shown in fig. 4a and 4b, an inwardly facing third sealing surface 156 is also formed on the upper portion of the first sealing surface 155. When the piston 160 moves to its top dead center of travel relative to the piston head 150, a corresponding portion on the inner race 162, such as the top of the inner race 162, will be in sealing contact with the third sealing surface 156. Thereby, the sealing effect between the piston head 150 and the piston 160 can be further improved.

As shown, the third sealing surface 156 is preferably a beveled surface. In addition, the third sealing surface 156 may take other forms, for example, the third sealing surface 156 may be a spherical surface or an arcuate transition surface of varying diameter.

Returning to fig. 2a and 3a, it can be seen that a first step 158 (fig. 2 a) is formed on the head 154 of the piston head 150, and correspondingly a second step 165 is formed on the lower portion of the inner ring 162 of the piston 160. When the piston 160 is at its bottom dead center of travel relative to the piston head 150, the second step 165 cooperatively abuts the first step 158, thereby preventing the piston 160 from continuing to move downward relative to the piston head 150 and disengaging from the piston head 150. Also, the fit between second step 165 and first step 158 may also serve as a seal.

Preferably, the inner diameter of the inner ring 162 of the piston 160 is set to be larger than the outer diameter of the piston head 150, particularly the outer diameter of the column portion 151, so that no frictional resistance is generated between the inner ring 162 and the column portion 151/head portion 154 when the piston 160 moves relative to the piston head 150. Thus, relative movement between the piston 160 and the piston head 150 may be facilitated, and wear on various components of the pump core mechanism 140 during use may also be reduced.

Preferably, the outer diameter a of the cylindrical portion 151 of the piston head 150 is designed to be larger than the outer diameter B of the head portion 154. Such a design facilitates demolding in the manufacture of piston head 150. Moreover, during installation of the piston 160 to the piston head 150, the piston 160 is sleeved onto the piston head 150 from the direction of the head 154, and thus making the outer diameter of the head 154 smaller may facilitate assembly of the piston 160 and the piston head 150 together.

In the preferred construction shown in the figures, the pump core mechanism 140 is mounted to the piston rod 130 by the cooperation of the piston head 150 with the piston rod 130. As shown in fig. 5, a plurality of female rings 159 may be provided on the inner surface of the cylindrical portion 151 of the piston head 150, and a plurality of male rings 131 may be provided on the outer surface of the lower portion of the piston rod 130, respectively. Female ring 159 and male ring 131 can snap fit into each other, thereby connecting piston head 150 to piston rod 130.

The operation of the push pump 100 of the above-described structure will be described in detail.

When the pressing pump 100 is pressed downward, the pressing head 110 of the pressing pump 100 is pressed to move downward, so that the piston rod 130 and the piston head 150 connected to the piston rod 130 also move downward. At this time, there is a frictional force between the outer ring 161 of the piston 160 and the cylinder wall, so that the piston 160 is kept stationary with respect to the cylinder and moves upward with respect to the piston head 150. During this process, the opening 157 in the piston head 150 is exposed, and the check valve is opened. Since the second sealing surface 163 includes the annular convex surface 164, only the annular convex surface 164 contacts the first sealing surface 155 when the piston 160 moves upward relative to the piston head 150, so that the resistance to movement between the piston 160 and the piston head 150 can be reduced.

Then, when the piston 160 moves to the top dead center of its stroke relative to the piston head 150, the top of the inner ring 162 contacts the third sealing surface 156, and the piston 160 moves downward relative to the cylinder along with the piston head 150. As the piston 160 moves downwardly relative to the cylinder, the pressure pressing the product within the pump 100 increases, thereby applying an upward thrust to the piston 160, which further compresses the sealing contact between the upper portion of the inner race 162 of the piston 160 and the third sealing surface 156.

When the pressing force on the ram 110 is removed, the ram 110 will return upward. At this time, the piston 160 remains stationary with respect to the cylinder and moves downward with respect to the piston head 150 by the frictional force between the outer race 161 of the piston 160 and the cylinder wall. Thereby, the upper portion of the inner ring 162 is out of contact with the third sealing surface 156, but the first and second sealing surfaces 155 and 163 are always in sealing contact. When the second step 165 of the piston 160 abuts the first step 158 of the piston head 150, the opening 157 is covered by the inner ring 162, so that the check valve is closed and the piston 160 will move upward along with the piston head 150. In the process, as the piston 160 moves upward relative to the cylinder, the space within the cylinder becomes larger, creating a negative pressure that draws the product in the container into the cylinder for the next use.

< second embodiment >

Fig. 6a and 6b show the structure of a pump core mechanism of a second embodiment of the present invention. The specific structure described above with respect to the first embodiment also applies to the second embodiment without a contrary description or conflict. The structure of the second embodiment different from the first embodiment will be specifically described below.

As with the first embodiment, in the second embodiment, the pump core mechanism includes a piston head 250 and a piston 260 mounted together, with the piston 260 being disposed over the piston head 250. The piston head 250 includes a cylindrical portion 251 and a skirt portion 252 depending from the cylindrical portion 251 and extending downwardly. The inner ring 262 of the piston 260 is movable up and down in the sandwich between the column portion 251 and the skirt portion 252.

Unlike the first embodiment, in the second embodiment, an annular convex surface 253 is formed on the inner surface of the skirt portion 252. When the inner ring 262 is sandwiched between the cylindrical portion 251 and the skirt portion 252, the annular convex surface 253 comes into contact with the outer surface of the inner ring 262, thereby achieving dynamic sealing between the piston head 250 and the piston 260.

Preferably, the annular convex surface 253 is disposed at or near a lower end of the inner surface of the skirt portion 252. In this way, it is ensured that there is always a seal between the piston head 250 and the piston 260.

< third embodiment >

Fig. 7a and 7b show the structure of a pump core mechanism according to a third embodiment of the present invention. The specific structures described above with respect to the first and second embodiments also apply to the third embodiment, without an adverse description or conflict. The structure of the third embodiment different from the first and second embodiments will be specifically described below.

In the third embodiment, the core mechanism includes a piston head 350 and a piston 360. Wherein the inner ring 362 is divided into an upper inner ring 365 and a lower inner ring 366. Specifically, web 367 connecting outer race 361 and inner race 362 serves as a boundary between upper inner race 365 and lower inner race 366. The inner surface of the skirt 352 forms a first sealing surface 355 and the outer surface of the upper inner ring 365 forms a second sealing surface 363.

Further, in the third embodiment, a fourth sealing surface 364 is formed at the connection between the upper inner ring 365 and the web 367. The fourth sealing surface 364 is preferably beveled. When the piston 360 moves relative to the piston head 350 to the point where it forms top dead center, a corresponding portion of the first sealing surface 355, such as the lower portion of the first sealing surface 355, will abut the fourth sealing surface 364, thereby achieving an additional sealing effect.

Of course, the fourth sealing surface 364 may have other forms than a beveled surface, such as a spherical surface, or an arcuate transition surface of varying diameter, and so forth.

< fourth embodiment >

Fig. 8a and 8b show the structure of a pump cartridge mechanism according to a fourth embodiment of the present invention. The specific structures described above with respect to the first to third embodiments also apply to the fourth embodiment without a contrary description or conflict. The structure of the fourth embodiment different from the first to third embodiments will be specifically described below.

In the fourth embodiment, the pump core mechanism includes a piston head 450 and a piston 460. Wherein an upper portion of the skirt portion 452 of the piston head 450 is formed with an outwardly facing fifth sealing surface 453, the fifth sealing surface 453 being formed, for example, at a location where the cylindrical portion 451 and the skirt portion 452 are joined.

When the piston 460 moves relative to the piston head 450 to the point where it forms the top dead center, a corresponding portion of the piston 460, for example, an upper portion of the inner ring 462, particularly a portion near the top thereof, will abut the fifth sealing surface 453, thereby obtaining an additional sealing effect.

In the configuration shown, the fifth sealing surface 453 is a chamfer. In addition, the fifth sealing surface 453 can be another type of surface, such as a spherical surface, an arcuate transition surface of varying diameter, or the like.

Claims (11)

1. A pump core mechanism is arranged in a pressing pump and comprises a piston head and a piston sleeved on the piston head, and is characterized in that,

the piston head comprises a column part and a skirt part, wherein the skirt part extends out of the outer surface of the column part and extends downwards to form an interlayer between the column part and the skirt part; and

the piston comprises an outer ring and an inner ring which are connected with each other, when the piston is sleeved on the piston head, the inner ring is inserted into the interlayer, and the piston can move up and down relative to the piston head, so that the inner ring can move up and down in the interlayer;

wherein the skirt is provided with a first sealing surface and the inner ring is provided with a second sealing surface, wherein the first sealing surface and the second sealing surface always cooperate to form a seal in a range between a stroke top dead center and a stroke bottom dead center of the piston relative to the piston head.

2. The pump cartridge mechanism of claim 1, wherein the first sealing surface is formed on an inner surface of the skirt and the second sealing surface is formed on an outer surface of the inner race, wherein one of the first and second sealing surfaces has an annular convex surface formed thereon that sealingly engages the other of the first and second sealing surfaces.

3. The pump cartridge mechanism of claim 2, wherein the annular convex surface is formed on an upper portion of the second sealing surface.

4. The pump cartridge mechanism of claim 2, wherein the annular convex surface is formed on a lower portion of the first sealing surface.

5. The core mechanism as claimed in claim 1, wherein said piston further includes a web connecting said outer ring with said inner ring, said web dividing said inner ring into an upper inner ring and a lower inner ring, and wherein at least one of the following sealing surfaces is further formed in said core mechanism:

a third sealing surface disposed on an upper portion of the first sealing surface and facing inward, wherein an upper portion of the second sealing surface is in sealing contact with the third sealing surface when the piston moves to a top dead center of travel relative to the piston head;

a fourth sealing surface formed at a position where the upper inner ring is connected to the web, wherein a lower portion of the first sealing surface is in sealing contact with the fourth sealing surface when the piston moves to a stroke top dead center with respect to the piston head; and

a fifth sealing surface formed on the upper portion of the skirt and facing outward, wherein the upper portion of the second sealing surface is in sealing contact with the fifth sealing surface when the piston moves to a top dead center of travel relative to the piston head.

6. The pump cartridge mechanism of claim 5, wherein at least one of the third seal face, the fourth seal face, and the fifth seal face is a ramped surface, a spherical surface, or a combination of a ramped surface and a spherical surface.

7. The pump core mechanism according to claim 1, wherein the piston head further comprises a head portion connected below the cylindrical portion, wherein an opening communicating an inside and an outside of the piston head is formed between the cylindrical portion and the head portion, and the opening cooperates with the inner race of the piston to form a check valve.

8. The pump core mechanism according to claim 7, wherein a first step portion is formed on the head portion, and a second step portion is formed on a lower portion of the inner race of the piston, and when the piston moves to a stroke bottom dead center with respect to the piston head, the first step portion comes into contact with the second step portion, preventing the piston from moving further downward with respect to the piston head.

9. The pump cartridge mechanism of claim 8, wherein an inner diameter of the inner race is greater than an outer diameter of the cylindrical portion and the head portion.

10. The pump cartridge mechanism of claim 8, wherein the cylindrical portion has an outer diameter greater than an outer diameter of the head portion.

11. A press pump comprising a press head and a mouthpiece, wherein the press head is movable in an up-and-down direction with respect to the mouthpiece, and a piston rod is provided below the press head, characterized in that a pump core mechanism according to any one of claims 1 to 10 is mounted on the piston rod.

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