Pre-pressing one-way valve assembly and all-plastic pressing pump comprising pre-pressing one-way valve assembly

Abstract

A pre-pressing one-way valve assembly is arranged in an all-plastic pressing pump and comprises a piston rod, a piston head and a piston of the all-plastic pressing pump. The pre-pressing one-way valve assembly further comprises an elastic pre-pressing piece arranged on one of the piston, the piston head and the piston rod. A first sealing part and a second sealing part are formed between the piston and the piston head or the piston rod, the second sealing part has a height in the axial direction of the all-plastic pressing pump, and the first sealing part and the second sealing part are arranged in the mode that when the piston moves upwards relative to the piston head, the first sealing part is opened first, and when the piston moves downwards relative to the piston head, the second sealing part is opened second. And after the piston is displaced upwards relative to the piston head by a distance reaching or exceeding the height of the second sealing part, the second sealing part is opened. According to the structure of the pre-pressing one-way valve assembly, the problem that the elastic pre-pressing piece is pressed for a long time and creeps can be solved, and meanwhile it can still be guaranteed that products are pumped outwards at preset pressure. The invention further relates to an all-plastic pressing pump comprising the pre-pressing one-way valve assembly.

Description

Technical Field

[0001] The present application relates to the field of packaging of liquid or semi-liquid products, and in particular to a fully plastic pump installed on a product container, and in particular to the design of a pre-pressure one-way valve in the fully plastic pump. Background Art

[0002] Press pumps are widely used in the fields of daily chemicals, food, and medicine. They are used to distribute liquid or semi-liquid products from containers for consumers. In order to improve the pumping efficiency of the product, or to achieve atomization of the product, a pre-pressing mechanism is provided in certain types of press pumps such as spray pumps. The pre-pressing mechanism presses on the piston to achieve a seal between the piston and the piston head. Only when the pressure of the product in the press pump is greater than the pressing force applied by the pre-pressing mechanism on the piston, the seal between the piston and the piston head can be released, thereby allowing the product to be pumped out. In this way, the pumped product itself has the required pressure, thereby improving the pumping efficiency of the product and achieving other requirements such as atomization of the product.

[0003] In traditional pumps, small metal springs are used as pre-stressing mechanisms. However, in order to meet the ever-increasing environmental protection requirements, more and more all-plastic pumps are used. In all-plastic pumps, plastic materials are used to make the pre-stressing mechanism. However, it was found during use that the pre-stressing mechanism made of plastic materials exhibited some problems. For example, the elastic force of the pre-stressing mechanism made of plastic is weaker than that of the metal spring, so the pre-stressing effect on the piston is not as good as that of the metal spring. Moreover, the plastic pre-stressing mechanism is more prone to creep after being compressed for a long time, resulting in a weakening or even loss of its elastic force, which leads to the attenuation of the pre-stressing function or even the eventual loss of the pre-stressing function. In specific applications such as spray pumps, this manifests itself in the generation of large droplets at the beginning and end of the distribution of the atomized product.

[0004] Therefore, in the field of press pumps, there is a demand for a further improved press pump structure to solve technical problems such as insufficient product pumping pressure and insufficient product atomization resulting in large droplets due to weak elasticity or loss of elasticity of the plastic pre-pressing mechanism. Summary of the invention

[0005] The present application is made to solve the technical problems existing in the above-mentioned prior art. The purpose of the present application is to provide a pre-compression check valve assembly for a press pump, and further to provide a fully plastic press pump including the pre-compression check valve assembly.

[0006] The present application provides a pre-stress one-way valve assembly, which is arranged in an all-plastic press pump, including a piston rod, a piston head and a piston of the all-plastic press pump, wherein the piston head is fixedly connected to the piston rod, and the piston is sleeved on the piston head. The pre-stress one-way valve assembly also includes an elastic pre-stressing member, which is arranged on one of the piston, the piston head and the piston rod. In the pre-stress one-way valve assembly, a first sealing portion is formed between the piston and the piston rod or the piston head, and a second sealing portion is also formed between the piston and the piston rod or the piston head, wherein the second sealing portion has a height along the axial direction of the all-plastic press pump, wherein the first sealing portion and the second sealing portion are arranged such that when the piston is displaced upward relative to the piston head, the first sealing portion is opened first, and after the distance of the upward displacement of the piston relative to the piston head reaches or exceeds the height of the second sealing portion, the second sealing portion is opened.

[0007] With the pre-stressed one-way valve assembly of the above structure, in the initial stage when the piston moves upward relative to the piston head, the first sealing part opens first, while the second sealing part remains sealed. Only when the piston moves upward by a distance equal to or greater than the height of the second sealing part, the second sealing part opens, and the pre-stressed one-way valve assembly is fully opened. Therefore, when not in use, the elastic pre-stressed part can be in a completely relaxed or relatively relaxed state, and only during the process of pressing and using, the elastic pre-stressed part is converted from a relaxed state to a loaded state. Moreover, during the pressing process, the elastic pre-stressed part is gradually loaded by pressure, and the pre-stressed one-way valve assembly is fully opened only after the elastic pre-stressed part has accumulated a certain amount of pressure. In this way, the problem of creep caused by long-term pressure on the elastic pre-stressed part can be solved, while still being able to ensure that the product is pumped out at a predetermined pressure.

[0008] In addition, at the end of pumping, the piston will shift downward relative to the piston head, so that the second sealing part forms a seal first, which will generate negative pressure in the pressing pump, thereby sucking back the residual droplets in the nozzle of the pressure head, avoiding the problem of large droplets dripping at the end of pumping.

[0009] In a specific structure, the piston has an outer ring and an inner ring, the lower end of the inner ring is formed with a first inclined surface, the piston head includes a sealing sleeve, the lower end of the sealing sleeve is formed with a second inclined surface, and the first inclined surface can cooperate with the second inclined surface to form a first sealing portion. In such a structure, the first sealing portion can be opened first during the pumping process.

[0010] Regarding the second sealing portion, in one embodiment, the sealing sleeve extends downward, and the sleeve outer side surface of the sealing sleeve can cooperate with the inner side surface of the inner ring of the piston to form the second sealing portion.

[0011] In another alternative embodiment, the sealing sleeve extends upward, and a gap is formed between the sealing sleeve and the body of the piston head, the gap can accommodate the inner ring, and the second inclined surface is formed at the bottom of the gap. The inner side surface of the sleeve of the piston head can cooperate with the outer side surface of the inner ring of the piston inner ring to form a second sealing portion.

[0012] Alternatively, in another alternative embodiment, the piston has an outer ring and an inner ring, a first inclined surface is formed at the lower end of the inner ring, the piston head includes a sealing sleeve, a second inclined surface is formed on the inner side of the sealing sleeve, and the first inclined surface can cooperate with the second inclined surface to form the first sealing portion. In addition, the second sealing portion can be formed by the inner side surface of the inner ring of the piston inner ring and the outer side surface of the piston rod of the piston rod.

[0013] In addition, the first sealing portion and the second sealing portion may also be formed between the piston and the piston rod.

[0014] Preferably, an inner cylinder is formed inside the sealing sleeve, which helps to reduce the dead volume area in the pump, thereby reducing the number of empty presses during use.

[0015] In a specific structure, the elastic pre-compression element includes a plurality of elastic strips.

[0016] Preferably, the elastic strip is formed into a "J" shape. In addition, these elastic strips can be arranged equidistantly in the circumferential direction. Of course, elastic strips of other numbers and shapes are also within the scope of the present application, and the spacing between the elastic strips can also be variable.

[0017] Preferably, at least one liquid guiding groove is formed on the body of the piston rod, the liquid guiding groove extends along the axial direction of the piston rod, and the liquid guiding groove cooperates with the piston rod inner hole of the piston rod to form a channel for the product to flow through.

[0018] Preferably, the piston rod is formed integrally with the piston head.

[0019] The present application also relates to an all-plastic press pump, which includes a pressure head, a toothed sleeve and a cylinder, wherein the toothed sleeve and the cylinder are fixedly connected together. The all-plastic press pump also includes the pre-pressing one-way valve assembly as described above, wherein the piston rod is connected to the lower part of the pressure head, the piston is located inside the cylinder, and is sealed with the inner surface of the cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings show non-limiting preferred implementation structures of the present invention, and the features and advantages of the present invention can be more clearly seen in conjunction with the accompanying drawings.

[0021] Figure 1 A cross-sectional view of the pressing pump according to the first embodiment of the present application is shown, wherein the pressing pump is in an upper standby state.

[0022] Figure 2 Another cross-sectional view of the pressing pump of the first embodiment is shown, in which the pressing pump is in a state of being pressed downward.

[0023] Figure 3a A perspective view of a pre-compression check valve assembly in a compression pump is shown.

[0024] Figure 3b Shows Figure 3a An exploded perspective view of a pre-loaded check valve assembly.

[0025] Figure 4a A cross-sectional view of a piston rod included in a pre-compression check valve assembly is shown.

[0026] Figure 4b A cross-sectional view of a piston included in a pre-compression check valve assembly is shown.

[0027] Figure 4c A cross-sectional view of a piston head included in a pre-compression check valve assembly is shown.

[0028] Figure 5a A cross-sectional view of the pre-compression check valve assembly is shown in a closed state.

[0029] Figure 5b A cross-sectional view of the pre-compression one-way valve assembly in the process of being opened is shown, wherein the first sealing portion is opened and the second sealing portion is still in a sealing state.

[0030] Figure 5c A cross-sectional view of the pre-compression check valve assembly is shown in a fully open state.

[0031] Figure 6 A second embodiment of a pre-compression check valve assembly for a compression pump is shown.

[0032] Figure 7 Shows Figure 6 A cross-sectional view of a piston head and a piston of a pre-loaded one-way valve assembly, wherein the piston is in an upwardly displaced position relative to the piston head.

[0033] Figure 8 An exploded cross-sectional view of a pre-compression check valve assembly for a compression pump according to a third embodiment is shown.

[0034] Fig. 9 Shows Figure 8 A cross-sectional view of a pre-pressurized one-way valve assembly in an assembled state, wherein the first sealing portion and the second sealing portion are sealed.

[0035] Fig.10 Shows Figure 8 Another cross-sectional view of the pre-pressurized one-way valve assembly in an assembled state, wherein the first sealing portion and the second sealing portion are released.

[0036] (Explanation of symbols)

[0037] 1 Press the pump

[0038] 11 Pressure head

[0039] 12 Braces

[0040] 13 cylinders

[0041] 14Elastic reset mechanism

[0042] 20 piston rod

[0043] 21 Elastic preload

[0044] 22 Piston rod inner hole

[0045] 23 Outer side of piston rod

[0046] 24 feeding holes

[0047] 25 Support flange

[0048] 30 piston head

[0049] 31 Liquid guide groove

[0050] 32 Sealing sleeve

[0051] 33 second slope

[0052] 34 sleeve outer side

[0053] 35 inner cylinder

[0054] 36 sleeve inner side

[0055] 40 piston

[0056] 41 outer ring

[0057] 42 inner circle

[0058] 43 First Incline

[0059] 44 Inner side of piston inner ring

[0060] 45 Outer side of piston inner ring DETAILED DESCRIPTION

[0061] The specific implementation of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be understood that the drawings only show preferred embodiments of the present invention, which do not constitute a limitation on the scope of the present invention. Those skilled in the art can make various obvious modifications, variations, and equivalent substitutions to the present invention based on the embodiments shown in the drawings, and the technical features of the different embodiments described below can be arbitrarily combined with each other without contradiction, which all fall within the scope of protection of the present invention.

[0062] <First Embodiment>

[0063] Figure 1 A cross-sectional view of a pressing pump 1 according to a first embodiment of the present application is shown, wherein the pressing pump 1 is in an upper standby state. Figure 2 Another cross-sectional view of the press pump 1 is shown, in which the press pump 1 is in a state of being pressed downward. The press pump 1 shown in the figure is specifically a spray pump, but the press pump 1 involved in the present application may also be other types of press pumps.

[0064] The pressing pump 1 includes a pressure head 11, a toothed sleeve 12 and a cylinder 13. The toothed sleeve 12 and the cylinder 13 are connected together. A piston rod 20 is connected to the lower part of the pressure head 11, for example, the piston rod 20 can be connected to the inner sleeve of the pressure head 11. The lower end of the piston rod 20 is connected to a piston head 30, and a piston 40 is sleeved on the outer periphery of the piston head 30. One end of the piston rod 20 provided with the piston 40 extends into the interior of the cylinder 13, and the piston 40 is sealed with the inner surface of the cylinder 13.

[0065] When the pressure head 11 is pressed downward, Figure 2 As shown in FIG, the piston rod 20 and the piston head 30 and piston 40 connected thereto move downward relative to the cylinder 13, so that the volume in the cylinder 13 decreases, and the pressure of the product therein increases. In addition, during the downward movement, due to the friction between the piston 40 and the inner wall of the cylinder 13, the downward movement of the piston 40 will lag relative to the piston head 30, so that the piston 40 is displaced upward relative to the piston head 30, so that the sealing fit between the piston 40 and the piston head 30 is released, and the passage leading to the nozzle of the pressure head 11 is opened, thereby allowing the product in the cylinder 13 to flow to the nozzle of the pressure head 11 and finally be dispensed.

[0066] After the pressure applied to the pressure head 11 is removed, the pressure head 11 can move upward relative to the mouthpiece 12 to return to the Figure 1The upper standby position is shown in FIG. 1 . For example, an elastic reset mechanism 14 may be provided between the ram 11 and the toothed brace 12 or the cylinder 13 to automatically move the ram 11 upward after the pressure is removed. The elastic reset mechanism 14 is, for example, a plastic spring made of plastic. Alternatively, the ram 11 may also be manually pulled upward to its upper standby position by a user, which is also within the scope of the present application. During the upward movement, due to the friction between the piston 40 and the inner surface of the cylinder 13, the position of the piston 40 relative to the piston head 30 will move downward, thereby forming a seal between the piston 40 and the piston head 30 to prevent product leakage.

[0067] Based on the above, it can be known that in the present application, the piston rod 20 , the piston head 30 and the piston 40 together constitute a one-way valve assembly in the pressing pump 1 , in particular, an upper one-way valve of the pressing pump 1 . Figure 3a shows a three-dimensional view of the one-way valve, Figure 3b 2 is an exploded perspective view showing the components of the one-way valve. An elastic preload 21 is provided at the lower end of the piston rod 20. The elastic preload 21 is made of plastic and can be integrally formed at the lower end of the piston rod 20 as shown in the figure, or can be formed separately and then mounted on the piston rod 20.

[0068] The elastic preload member 21 may include a plurality of elastic strips, such as four elastic strips arranged at equal intervals along the circumference of the piston rod 20 as shown in the figure, and the four elastic strips may be roughly in a "J" shape. The free ends of the elastic strips may abut against the piston 40 to apply preload to the piston 40. In an exemplary structure, the free ends of the elastic strips of the elastic preload member 21 abut against the connecting web between the inner ring and the outer ring of the piston 40.

[0069] The elastic preload 21 may also include other numbers of elastic strips, such as two, three, five, etc. The elastic strips may also take other shapes, such as bow-shaped, S-shaped, etc., or the elastic preload 21 may take other structures besides elastic strips, all of which are within the scope of the present application.

[0070] Figures 4a to 4c The cross-sectional views of the piston rod 20, the piston head 30 and the piston 40 are shown respectively, from which the decoupling of the components can be more clearly seen.

[0071] like Figure 4a As shown, the lower end of the piston rod 20 is provided with an elastic pre-compression member 21, which may include, for example, at least one, preferably a plurality of elastic strips. A piston rod inner hole 22 is formed inside the piston rod 20, and the piston rod inner hole 22 preferably extends through the piston rod 20 in the longitudinal direction.

[0072] The piston 40 includes an outer ring 41 and an inner ring 42, and the outer ring 41 and the inner ring 42 are connected by a web. The outer ring 41 of the piston 40 can be sealed with the inner surface of the cylinder 13. A first inclined surface 43 is formed at the lower end of the inner ring 42 of the piston 40, and the position above the first inclined surface 43 on the lower surface of the inner ring 42 is the inner side surface 44 of the piston inner ring. The inner side surface 44 of the piston inner ring extends substantially in the longitudinal direction of the piston 40 and has a height H1 (at Figure 5a The first inclined surface 43 of the inner ring 42 and the inner side surface 44 of the piston inner ring can be sealed and disengaged with the corresponding structure on the piston head 30, so as to realize the closing and opening of the one-way valve, as will be described in more detail below.

[0073] like Figure 4c As shown, the piston head 30 includes a body and a sealing sleeve 32 formed below the body. At least one liquid guide groove 31 is formed on the body of the piston head 30, and the liquid guide groove 31 cooperates with the inner wall of the piston rod inner hole 22 of the piston rod 20 to form a liquid channel for the product to pass through. The liquid or semi-liquid product can enter the channel in the pressure head 11 through the liquid channel and reach the nozzle of the pressure head 11.

[0074] A second inclined surface 33 is formed at or near the lower end of the sealing sleeve 32, and the second inclined surface 33 can cooperate with the first inclined surface 43 of the inner ring 42 of the piston 40 to form a first sealing portion. In addition, above the second inclined surface 33 is a sleeve outer surface 34 of the sealing sleeve 32, and the sleeve outer surface 34 cooperates with the piston inner ring inner surface 44 of the inner ring 42 of the piston 40 to form a second sealing portion.

[0075] Next, see Figure 5a to 5c , which shows how the check valve assembly operates.

[0076] exist Figure 5a In the state shown, the one-way valve assembly is in a closed state, which corresponds to the upper standby state of the pressing pump 1. Figure 5a In the state shown, the first inclined surface 43 of the inner ring 42 of the piston 40 cooperates with the second inclined surface 33 of the sealing sleeve 32 of the piston head 30 to form a first sealing portion, and the inner ring inner surface 44 of the inner ring 42 of the piston 40 cooperates with the sleeve outer surface 34 of the sealing sleeve 32 to form a second sealing portion. At this time, the elastic preload member 21 is in a relaxed state.

[0077] Next, when the pressure head 11 is pressed downward, the pressure head 11 moves downward with the piston rod 20 and the piston head 30. There is friction between the piston 40 and the inner surface of the cylinder 13, so the piston 40 moves upward relative to the position of the piston head 30, and the first inclined surface 43 of the piston 40 is out of contact with the second inclined surface 33 of the piston head 30, thereby releasing the first sealing portion, such as Figure 5bAt this time, the outer side surface 34 of the sleeve and the inner side surface 44 of the inner ring of the piston are still in contact, thereby maintaining the second sealing portion. In this process, the elastic pre-pressing member 21 enters the loaded state from the relaxed state, and because the second sealing portion is still sealed, the product that is not fully pressurized will not flow out.

[0078] Then, if Figure 5c As shown, as the piston 40 continues to shift upward relative to the piston head 30, when the distance that the piston 40 shifts upward relative to the position of the piston head 30 reaches or exceeds the height H1 of the inner side surface 44 of the piston inner ring, the inner side surface 44 of the piston inner ring is separated from the contact with the outer side surface 34 of the sleeve, so that the second sealing portion is released. At this time, the one-way valve assembly is fully opened, allowing liquid or semi-liquid products to flow through. In the process of the piston 40 shifting upward relative to the piston head 30 to a distance equal to the height H1, the elastic preload 21 is gradually loaded, and the pressure of the product in the cylinder 13 is gradually accumulated. When both the first sealing portion and the second sealing portion are released, the product pressure reaches the required pressure and can flow through the one-way valve assembly.

[0079] When pumping is finished, the piston 40 moves downward relative to the piston head 30, the inner side surface 44 of the piston inner ring contacts the outer side surface 34 of the sleeve first, and the second sealing part is sealed. At this time, the volume of the space in the cylinder 13 increases and the pressure decreases, thereby forming a negative pressure, which can suck back the droplets in the nozzle of the pressure head 11, thereby preventing the problem of large droplets leaking at the end of pumping.

[0080] Therefore, in the above-mentioned one-way valve assembly, in the standby state ( Figure 5a ), the elastic pre-compression member 21 can be in a relaxed state, and during the pressing process, the elastic pre-compression member 21 is gradually loaded during the initial pressing process, and the one-way valve assembly is not fully opened during this process, thereby allowing the product in the cylinder 13 to be gradually pressurized. When the one-way valve assembly is fully opened, the product also reaches the required pressure. Therefore, in the standby state, the elastic pre-compression member 21 can be in a completely relaxed or relatively relaxed state, and the elastic pre-compression member 21 is only loaded during the pressing process, thereby preventing or at least alleviating the problem of creep of the elastic pre-compression member 21 due to long-term pressure, while still ensuring that the pumped product has a predetermined pressure. In addition, when pumping is finished, the second sealing portion first realizes sealing to form a negative pressure, so that the product droplets remaining in the nozzle of the pressure head 11 can be sucked back to avoid the problem of large droplets dripping.

[0081] Preferably, as shown in the figure, an inner cylinder 35 is further provided inside the sealing sleeve 32. By providing the inner cylinder 35, the dead volume in the cylinder 13 can be reduced, and the number of air compression times when pumping the product can be reduced.

[0082] <Second Embodiment>

[0083] Figure 6 and 7 The one-way valve assembly used in the pressing pump 1 of the second embodiment of the present application is shown. Unless otherwise stated or obviously contradictory, the technical features described in the first embodiment above are also applicable to the second embodiment, and vice versa. Here, the technical features identical to those in the first embodiment will not be described in detail, and only the technical features not mentioned in the first embodiment will be disclosed in detail.

[0084] In the one-way valve assembly of the second embodiment, a sealing sleeve 32 is provided at the lower end of the piston head 30, and the sealing sleeve 32 extends upward. A gap is formed between the sealing sleeve 32 and the body of the piston head 30, and the inner ring 42 of the piston 40 can be received in the gap. A second inclined surface 33 is formed at the bottom of the gap, and the second inclined surface 33 can cooperate with the first inclined surface 43 of the inner ring 42 to form a first sealing portion. The inner ring 42 also includes a piston inner ring outer side surface 45 with a certain height, and the piston inner ring outer side surface 45 can cooperate with the sleeve inner side surface 36 of the sealing sleeve 32 to form a second sealing portion.

[0085] Similar to the first embodiment, during the pressing process, the piston 40 moves upward relative to the piston head 30, the first inclined surface 43 is disengaged from the second inclined surface 33, and the first sealing portion is released first. As the piston 40 continues to move upward for a distance, the outer side surface 45 of the piston inner ring is disengaged from the inner side surface 36 of the sleeve, so that the second sealing portion is released.

[0086] <Third Embodiment>

[0087] Figures 8 to 10 The one-way valve assembly used in the pressing pump 1 of the third embodiment of the present application is shown. Unless otherwise stated or obviously contradictory, the technical features described in the first and second embodiments above are also applicable to the third embodiment, and vice versa. Here, the technical features that are the same as those in the first and second embodiments are not described in detail, and only the technical features that are not mentioned in the first and second embodiments are disclosed in detail.

[0088] Figure 8 , which is a disassembled cross-sectional view of the one-way valve assembly. Similar to the first and second embodiments, a first inclined surface 43 is formed on the outer surface of the lower portion of the inner ring 42 of the piston 40. In addition, in the third embodiment, a sealing sleeve 32 extending upward is provided on the upper portion of the piston head 30, and a second inclined surface 33 is formed on the inner side of the sealing sleeve 32. The first inclined surface 43 can cooperate with the second inclined surface 33 to form a first sealing portion, such as Fig. 9 The status shown in .

[0089] In addition, the inner side surface 44 of the inner ring of the piston 40 has a certain height and can cooperate with the outer side surface 23 of the piston rod 20 to form a second sealing portion, such as Fig. 9 The status shown in .

[0090] An elastic preload piece 21 is disposed at the upper end of the piston 40 , and the upper end of the elastic preload piece 21 is a free end. A radially extending support flange 25 is formed on the outer peripheral surface of the piston rod 20 , and the free end of the elastic preload piece 21 is supported on the support flange 25 .

[0091] For the structure of the one-way valve assembly of the third embodiment, during the pressing and using process, the piston 40 moves upward relative to the piston head 30 and the piston rod 20, and first the first inclined surface 43 and the second inclined surface 33 are disengaged from each other, so that the first sealing portion is released. As the piston 40 continues to move upward until the feed hole 24 on the piston rod 20 leading to the inner hole 22 of the piston rod is exposed, the second sealing portion is released.

[0092] The above describes the structure of the specific embodiment of the present application in detail. It is known to those skilled in the art that various obvious modifications, variations and combinations can be made based on the disclosed structure, which are also within the scope of the present application.

[0093] For example, the piston head 30 and the piston rod 20 may be connected in various ways, such as the retaining ring-retaining groove structure shown in the figure, or a threaded connection structure, or the piston head 30 may be formed integrally with the piston rod 20.

[0094] The elastic preload 21 can be formed integrally on the piston rod 20, or can be manufactured separately and then mounted on the piston rod 20. The elastic preload 21 can include any desired number and shape of elastic strips, and the multiple elastic strips can be equally spaced or have varying spacing.

[0095] In the embodiments disclosed above, the first sealing portion and the second sealing portion are formed between the piston 40 and the piston head 30, or one is formed between the piston 40 and the piston head 30, and the other is formed between the piston 40 and the piston rod 20. In addition, the first sealing portion and the second sealing portion may also be formed between the piston 40 and the piston rod 20, which is also within the scope of the present application.

[0096] In the structures disclosed above, in the first and second embodiments, the elastic preload 21 is formed or connected to the piston rod 20, or as in the third embodiment, the elastic preload 21 is formed on the piston 40, and a supporting flange for the elastic preload 21 to abut is provided on the piston rod 20. In addition, the elastic preload 21 may also be formed on the piston head 30. Alternatively, in the case where the elastic preload 21 is formed on the piston 40, a supporting portion cooperating with the elastic preload 21 may also be provided on the piston head 30. These variations are also within the scope of the application.

Claims

1. A pre-compression check valve assembly, the pre-compression check valve assembly is arranged in an all-plastic press pump, the pre-compression check valve assembly comprises a piston rod, a piston head and a piston of the all-plastic press pump, the piston head is fixedly connected to the piston rod, the piston sleeve is arranged on the piston head, the pre-compression check valve assembly also comprises an elastic pre-compression member, the elastic pre-compression member is arranged on one of the piston, the piston head and the piston rod, characterized in that: A first sealing portion is formed between the piston and the piston rod or the piston head, and a second sealing portion is also formed between the piston and the piston rod or the piston head, wherein the second sealing portion has a height along the axial direction of the all-plastic pressure pump, wherein the first sealing portion and the second sealing portion are arranged such that when the piston is displaced upward relative to the piston head, the first sealing portion is opened first, and after the distance that the piston is displaced upward relative to the piston head reaches or exceeds the height of the second sealing portion, the second sealing portion is opened.

2. The pre-compression check valve assembly according to claim 1, characterized in that: The piston has an outer ring and an inner ring, the lower end of the inner ring is formed with a first inclined surface, the piston head includes a sealing sleeve, the lower end of the sealing sleeve is formed with a second inclined surface, and the first inclined surface can cooperate with the second inclined surface to form the first sealing portion.

3. The pre-compression check valve assembly according to claim 2, characterized in that: The sealing sleeve extends downward, and the outer side surface of the sealing sleeve can cooperate with the inner side surface of the inner ring of the piston to form the second sealing portion.

4. The pre-compression check valve assembly according to claim 2, characterized in that: The sealing sleeve extends upward, a gap is formed between the sealing sleeve and the body of the piston head, the gap can accommodate the inner ring, and the second inclined surface is formed at the bottom of the gap; and The inner side surface of the sleeve of the piston head can cooperate with the outer side surface of the piston inner ring of the inner ring to form the second sealing portion.

5. The pre-compression check valve assembly according to claim 1, characterized in that: The piston comprises an outer ring and an inner ring, a first inclined surface is formed at the lower end of the inner ring, the piston head comprises a sealing sleeve, a second inclined surface is formed on the inner side of the sealing sleeve, and the first inclined surface can cooperate with the second inclined surface to form the first sealing portion; and / or The inner side surface of the inner ring of the piston inner ring can cooperate with the outer side surface of the piston rod of the piston rod to form the second sealing portion.

6. The pre-compression check valve assembly according to claim 2, characterized in that: An inner cylinder is formed inside the sealing sleeve.

7. The pre-compression check valve assembly according to any one of claims 1 to 6, characterized in that: The elastic pre-pressing member comprises a plurality of elastic strips.

8. The pre-compression check valve assembly according to claim 7, characterized in that: The elastic strips are formed in a "J" shape, and / or the elastic strips are arranged equidistantly along the circumferential direction.

9. The pre-compression check valve assembly according to any one of claims 1 to 6, characterized in that: At least one liquid guiding groove is formed on the body of the piston rod. The liquid guiding groove extends along the axial direction of the piston rod and cooperates with the piston rod inner hole of the piston rod to form a channel for the product to flow through.

10. The pre-compression check valve assembly according to any one of claims 1 to 6, characterized in that: The piston rod is formed integrally with the piston head.

11. An all-plastic compression pump, comprising a pressure head, a toothed sleeve and a cylinder, wherein the toothed sleeve and the cylinder are fixedly connected together, characterized in that: The all-plastic pressing pump comprises a pre-pressure one-way valve assembly as described in any one of claims 1 to 10, wherein the piston rod is connected to the lower part of the pressure head, and the piston is located inside the cylinder and is sealed with the inner surface of the cylinder.

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