Gap sealing device

Abstract

The present invention relates to a gap seal device comprising a housing (2) having a guide chamber (22) filled with a fluid, and a multi-component piston (3) that is moved translationally and / or rotationally within the guide chamber (22), the piston (3) separating a high-pressure region (23) from a low-pressure region (24) of the guide chamber (22), the piston (3) forming an annular gap (9) with an inner wall (25) that bounds the guide chamber (22) and has a nominal gap width (S0). The piston (3) comprises a stepped rod (4), a sleeve (5) sliding on the stepped reduced diameter region (42) of the rod (4) and having a blind hole (54), and a coupling portion (7), wherein at least one stiffness change portion (43, 56) is provided in the stepped reduced diameter region (42) of the rod (4) or in the tubular portion (52) of the sleeve (5), and a gap width (SV) of the annular gap (9) smaller than the nominal gap width (S0) is set in the radial region of the stiffness change portion (43, 56) as a function of a set stress (F) due to stress-induced expansion in the outer diameter direction of the tubular portion (52) of the sleeve (5).

Description

[Technical Field]

[0001] The present invention relates to the gap sealing device described in the preceding part of claim 1. [Background technology]

[0002] A general gap sealing device is known, for example, from European Patent No. 1353096. In this publication, a sealing ring is used to seal a movable shaft or rod in the transition region between the high-pressure and low-pressure regions of the guide chamber of a housing that guides the rod. The sealing ring encloses the shaft or rod and is partially deformed by the high pressure applied in the high-pressure region with the help of a pressure ring. As a result of the deformation of the sealing ring, the gap between the sealing ring and the shaft is reduced to such an extent that only a desired amount of fluid leakage passes through. Such gap sealing devices have been proven effective in practice.

[0003] The objective of the present invention is to provide a gap sealing device that does not require such seal rings or pressure rings, while keeping manufacturing costs low. [Overview of the project] [Means for solving the problem]

[0004] This objective is achieved by a gap sealing device having the features of claim 1.

[0005] The gap seal device according to the present invention has a housing comprising a guide chamber filled with fluid and a piston consisting of a plurality of parts that can move translationally and / or rotationally within the guide chamber.

[0006] The piston has an inner wall of a housing that divides the guide chamber, and separates the low-pressure region from the high-pressure region of the guide chamber by forming an annular gap with a nominal gap width. The piston has a stepped rod, a sleeve with a blind hole fitted onto the stepped reduced diameter region of the rod, and a coupling.

[0007] The rod can be subjected to stress through the joint and sleeve. The tubular portion of the sleeve or the stepped diameter reduction region of the rod exhibits at least one change in stiffness, particularly a form of material weakening.

[0008] The gap width of the annular gap, which is smaller than the nominal gap width, is adjusted in the radial region of the stiffness change area as a function of the set stress, due to expansion induced by the outer diameter stress of the tubular portion of the sleeve.

[0009] In this type of gap sealing device, the gap dimension of the annular gap for sealing the low-pressure region to the high-pressure region of the guide chamber can be easily adjusted by changing the tension of the rod or sleeve, thereby easily changing the sealing effect or leakage amount of the gap sealing device.

[0010] Modifications of advantageous embodiments of the present invention are the subject matter of the dependent claims. It is desirable to apply stress to the sleeve in order to enlarge the outer diameter of the tubular portion of the sleeve.

[0011] According to the first preferred further development example, the rod can be subjected to stress through the joint and sleeve.

[0012] According to a modification of an advantageous embodiment, for this purpose the rod is configured as a hollow rod having a through hole in which a retractable rod is housed, the retractable rod is guided through the through hole of the hollow rod, and stress can be applied to the hollow rod by connecting a first end of the retractable rod to a joint and a second end of the retractable rod to a sleeve.

[0013] By configuring the rod as a hollow rod having a retractable rod housed therein, it becomes possible to apply stress to the rod or the sleeve in a simple manner.

[0014] According to a further advantageous development example, the coupling part has a blind hole provided with an internal thread, where the external thread of the first end of the retractable rod is screwed into the internal thread, and by rotation around the longitudinal axis of the retractable rod, an axially acting stress is applied to the hollow rod.

[0015] Thereby, by turning the coupling part, the pressure on the hollow rod and thus the size of the annular gap can be easily adjusted.

[0016] According to another embodiment, the rigidity changing part is formed as a material recess on the inner circumference of the stepped part of the hollow rod. Such a material recess can be produced in a simple manner within the hollow rod.

[0017] In an alternative embodiment, the rod is configured as a stepped solid rod. In particular, the rod can also be formed integrally with the coupling part. Using a modification of such an embodiment, it is also possible to apply stress to the sleeve with respect to the rod.

[0018] In order to apply stress, in a preferred embodiment, the rod has a first end provided with an external thread, which is screwed into the internal thread of the sleeve. For stress application by a coupling part configured as a separate component, the rod preferably has a second end provided with an external thread that is screwed into the internal thread of the coupling part.

[0019] According to a modification of an alternative embodiment, the rigidity changing part is formed as a material recess on the inner circumference of the tube part of the sleeve. Thereby, a desired expansion of the outer diameter can also be achieved in a simple manner.

[0020] The material recess is preferably designed as an annular recess, thus enabling uniform changes in the circumferential direction of the outer diameter of the sleeve's tube portion.

[0021] According to a variant of a further advantageous embodiment, the sleeve is axially adjustable with respect to the draw-in rod along the longitudinal axis of the draw-in rod. Thereby, the outer diameter expansion position of the sleeve's tube portion can be adjusted axially along the draw-in rod.

Brief Description of the Drawings

[0022] Preferred exemplary embodiments will be described in more detail below with reference to the accompanying drawings. [Figure 1] A cross-sectional view according to a variant of an embodiment of the gap seal device according to the present invention is shown. [Figure 2] A partial cross-sectional view in the stress state of the gap seal device shown in FIG. 1 is shown. [Figure 3] The gap seal device corresponding to FIG. 2 is shown, indicating the pressure drop before the expansion region of the sleeve's tube portion. [Figure 4] A detailed view of the portion marked IV in FIG. 3 under additional deformation caused by the applied operating stress is shown. [Figure 5] Another variant of an embodiment of the gap seal device according to the present invention, with a rigidity change portion of the sleeve's tube portion, is shown corresponding to FIG. 1. [Figure 6] Another variant of an embodiment of the gap seal device according to the present invention, with a rigidity change portion of the sleeve's tube portion, is shown corresponding to FIG. 1. [Figure 7] Another variant of an embodiment of the gap seal device according to the present invention, with a rigidity change portion of the sleeve's tube portion, is shown corresponding to FIG. 1. [Figure 8] Another variant of an embodiment of the gap seal device according to the present invention, with a rigidity change portion of the sleeve's tube portion, is shown corresponding to FIG. 1.

Modes for Carrying Out the Invention

[0023] In the following diagram descriptions, terms such as top, bottom, left, right, front, and rear refer exclusively to exemplary representations and positions of gap seal devices, housings, pistons, rods, sleeves, couplings, retractable rods, etc., selected in each diagram. These terms should not be understood restrictively; rather, different working positions or mirror-symmetric configurations may cause variations in these references.

[0024] In Figures 1 to 3, reference numeral 2 denotes a housing having a fluid-filled guide chamber 22, within which a piston 3 consisting of multiple parts can be translated and / or rotated.

[0025] The housing 2 can be configured as a component of the vibrating plunger pump, and within the housing, as shown in Figure 1, the piston vibrates in the longitudinal direction L in the translational direction T toward the guide chamber 22 during the operating cycle (suction and pressure stroke).

[0026] The piston 3 forms an annular gap 9 having an inner wall 25, which defines the boundary of the guide chamber 22 and separates the high-pressure region 23 of the guide chamber 22 from the low-pressure region 24. As shown in Figure 1, the piston 3 is composed of several parts. The piston 3 has a stepped rod 4 in the form of a hollow rod having a through hole 46, and a sleeve 5 fitted onto a stepped reduced diameter region 42 of the hollow rod 4.

[0027] The outer diameter of sleeve 5 is equal to the outer diameter d of the guide area 41 of rod 4. K This corresponds to the stepped diameter reduction region 42 of the rod 4, which is dimensioned so that its outer diameter portion contacts the inner wall of the tubular portion 52 of the sleeve 5. The sleeve 5 further has a blind hole 54 in the head portion 51 of the sleeve 5, which is used to receive the retraction rod 6 that passes through the through hole 46 of the rod 4.

[0028] In this case, the first end 61 of the retraction rod 6 is received by the joint 7 and is located in the blind hole 72. By connecting the first end 61 of the retraction rod 6 to the joint 7 and the second end 62 of the retraction rod 6 to the sleeve 5, stress can be applied to the hollow rod 4 by bringing the joint 7 closer to the sleeve 5.

[0029] As shown in the modified embodiment of Figure 1, the rod 4, which is configured as a hollow rod, exhibits a change in rigidity in its stepped diameter reduction region 42, which in this case takes the form of material weakening 43. In addition to material weakening, which manifests as the removal of the target material, the stiffness change region can also be understood as, for example, a material cross-section with a lower modulus of elasticity.

[0030] In the modified versions of the alternative embodiments shown in Figures 5 and 6, the tubular portion 52 of the sleeve 5 has such a rigidity change portion 56. Due to these stiffness-changing sections 43 and 56, as shown in Figure 2, the width of the annular gap 9 in the radial region relative to the stiffness-changing sections 43 and 56 of the hollow rod 4 is changed from the nominal gap width S0 to the gap width S as a function of the set stress F. V It can be adjusted to the gap width S V This is smaller than the nominal gap width S0.

[0031] In the modified embodiments shown in Figures 5 and 6, the tubular portion 52 of the sleeve 5 is directly expanded by tightening the sleeve 5 against the joint 7 in the region of the stiffness change portion 56, whereas in the modified embodiments shown in Figures 1 to 3, the stepped diameter reduction region 42 of the hollow rod 4 equipped with the stiffness change portion 43 is pressed radially outward against the tubular portion 52 of the sleeve 5 as a result of stress, which leads to expansion of the outer diameter of the tubular portion 52 of the sleeve 5 in this region.

[0032] In a modified version of the preferred embodiment, a female thread 73 is provided in the blind hole 72 of the joint 7 to generate stress in the hollow rod 4, so that the first end 61 of the retraction rod 6 can be screwed into the male thread 63.

[0033] By rotating the coupling head 71 of the coupling part 7 in the rotational direction R about the longitudinal axis L of the retraction rod 6, the distance between the coupling head 71 and the sleeve 5 can be slightly reduced, and as a result, an axial force acts on the hollow rod 4, and this force covers the coupling head 71 It can be adjusted according to the rotation angle and the pitch of screws 63 and 73.

[0034] The hollow rod 4 deforms due to the force acting on it in the axial direction. The formation of the rigidity change section 43 determines the position of this deformation, similar to the deformation direction on the radially outward side.

[0035] This radially outward deformation results in an expansion of the outer diameter of the tubular portion 52 of the sleeve 5, as schematically shown in Figure 2. In the region of its second end 62, the retraction rod 6 is also preferably provided with a male thread 63 into which the sleeve 5 can be screwed. As a result, the sleeve 5 is also held axially on the retraction rod 6.

[0036] In this case, the force applied axially via the joint 7 is transmitted by the inner end wall 53 on the head portion 51 of the sleeve 5, and the pressure surface 47 of the stepped diameter reduction region 42 of the hollow rod 4 remains stationary against this force. The end face of the tubular portion 52 of the sleeve 5 is separated from the stepped portion 44 of the hollow rod 4 by a gap 10 at the transition from the guide region 41 to the stepped diameter reduction region 42.

[0037] Furthermore, it is preferable that the rigidity change portion 43 in the modified embodiment shown in Figures 1 to 3 is formed as a material recess on the inner circumference of the stepped diameter reduction region 42 of the hollow rod 4. In the modified embodiments shown in Figures 5 and 6, it is desirable that the rigidity change portion 56 be formed as a material recess on the inner circumference of the tubular portion 52 of the sleeve 5.

[0038] These stiffness-changing portions 43 and 56 are formed as material recesses, and in this case, it is preferable that they be formed as annular recesses. Furthermore, as shown in Figure 2, it is also conceivable to vary the rigidity in several steps along the longitudinal axis L to distribute the sealing effect to several pressure reduction regions, or to enlarge the guide portion of the piston 3.

[0039] In a further embodiment, the sleeve 5 is axially adjustable relative to the retraction rod 6 with respect to the longitudinal axis L of the retraction rod 6.

[0040] Furthermore, the deformation 55 in the outer diameter portion of the tubular section 52 of the sleeve 5 is adjusted so that the gap width becomes smaller than the nominal gap width S0 after the stress is set via the joint 7, and in an exemplary use of a gap sealing device in an oscillating plunger pump, the high-pressure region 23 can be filled with fluid in the suction stroke and compression can be performed in the pressure stroke.

[0041] During this pressure stroke, as shown in Figures 3 and 4, the high pressure acting on the end face 57 of the sleeve 5 causes further deformation of the tubular portion 52 of the sleeve 5, further reducing the annular gap 9 to a gap width S. K This reduces the pressure, further promoting fluid sealing in the compressed space that forms the high-pressure region 23, and further reducing leakage.

[0042] Figure 3 schematically shows a pressure curve p to illustrate the pressure drop on the inner surface of the main body 21 of the housing 2, which marks the boundary of the guide chamber 22. It is intended to represent the gradually decreasing high pressure p acting on the inner surface of the housing 2, and follows the function p = f(x), where the high pressure p depends on the expansion of the gap S in the longitudinal direction X.

[0043] In principle, such a gap seal device could also be used in a rotating system in which the piston 3 rotates within the housing 2, and the high-pressure space, in this case the high-pressure region 23, must be sealed away from the low-pressure region 24.

[0044] In a modification of the embodiment shown in FIGS. 5 and 6, a rigidity change portion 56 is provided on the inner periphery of the pipe portion 52 of the sleeve 5, and the pressure surface 47 to which the stress applied by the coupling portion 7 is applied is equal to the stepped portion 44 of the hollow rod 4 in the transition region between the guide region 41 and the stepped reduced-diameter region 42.

[0045] Here, the end face of the stepped reduced-diameter region 42 of the hollow rod 4 is separated from the inner end wall 53 of the sleeve 5 by a gap 10. FIG. 6 also shows two modifications 55, 55' of different sizes, where modification 55 is generated by stress application and modification 55' is generated by further compression of the fluid under high pressure.

[0046] The pressure is preferably between 150 bar (152.9 Kg / cm 2 ) and 8000 bar (8157.7 Kg / cm 2 ), particularly preferably between 1500 bar (1529.5 Kg / cm 2 ) and 6000 bar (6118.3 Kg / cm 2 ). In the low-pressure region 24, the fluid is preferably under a pressure of 1 bar to 16 bar. Due to the high pressure in the high-pressure region 23 extending through the high-pressure chamber 8 into the guide chamber 22 of the housing 2, this pressure difference causes a slight deformation on the inside of the housing 2 as shown in FIG. 4.

[0047] In response to the presence of high pressure, the deformation 55 in the pipe portion 52 of the sleeve 5 increases as the width S of the remaining sealing gap K approaches zero, and thus leakage of the fluid from the high-pressure state into the low-pressure region can be completely or almost completely prevented.

[0048] FIGS. 7 and 8 further show modifications of two further alternative embodiments of the gap seal device according to the present invention, in which case they each comprise a solid rod or a mass-formed rod. In these modifications, the rod 4 has a first end portion 48 provided with a male thread, and the first end portion 48 is screwed into the female thread of the sleeve 5.

[0049] Therefore, the rod 4 also has a second end 49 with a male thread that is screwed into the female thread 73 of the joint 7. Other joint configurations that can apply stress to or connect the rod 4 in the axial direction L are also conceivable.

[0050] At this time, the two ends 48 and 49 are the guide area of ​​the rod 4. 41 Protruding from the end face, guide area 41 diameter d K It has a smaller diameter than that. In the modified example shown in Figure 7, the outer surface of the stepped diameter reduction region 42 surrounded by the sleeve 5 is in contact with the inner surface of the tubular portion 52 of the sleeve 5, except for the rigidity change portion 56 formed as a material recess.

[0051] Next, this stepped diameter reduction region 42 is at the first end of the rod 4 48 Adjacent to this first end 48 It is screwed into the head portion 51 of sleeve 5. In the modified embodiment shown in Figure 8, the stepped diameter reduction region 42 is smoothly formed at the first end 48 The tubular portion 52 of the sleeve 5, which is coupled to the sleeve 5 and as a result has a rigidity change portion 56 formed on its inner side surface, does not come into contact with the outer side surface of the stepped diameter reduction region 42 surrounded by the sleeve 5.

[0052] Alternatively, the rod could be constructed as an integral part of the joint. Furthermore, in the modified embodiments of these embodiments, the stress in the rod 4 changes from the nominal gap width S0 to the stress gap width S V This allows for an initial reduction in the width of the annular gap 9 up to the point where pressure is applied, and the gap width S K It is important that this can be further reduced. [Explanation of symbols]

[0053] 2 Housing 21 Main unit 22 Guide Chamber 23 High-voltage area 24 Low-pressure area 3 pistons 4 rods 41 Guidance Area 42 stepped reduced diameter region 43. Part where stiffness changes 44 Step part 45 First end face 46 Through hole 47 Pressure surface 48 First end 49 Second end 5 sleeves 51 Head section 52 Pipe section 53 Internal end wall 54 blind holes 55 Deformed part 56. Part where stiffness changes 57 End face 6 Retractable rod 61 First end 62 Second end 63 Male screw 7 Joint 71 Joint head 72 blind holes 73 Female thread 8. High-pressure chamber 9. Ring Gap 10 Gap S Gap width S0 Nominal Gap Width S V Gap width S K The gap width under stress and with high pressure applied. L Longitudinal axis T translational direction R rotation direction X direction Y direction d K diameter p pressure

Claims

1. A housing (2) having a guide chamber (22) filled with fluid, The piston (3) comprises a plurality of parts that can be moved translationally and / or rotationally within the guide chamber (22), In a gap sealing device, the piston (3) separates the high-pressure region (23) of the guide chamber (22) from the low-pressure region (24) of the guide chamber (22), and the piston (3), together with the inner wall (25) that partitions the guide chamber (22), forms an annular gap (9) having a gap width (S0). The piston (3) comprises a stepped rod (4), a sleeve (5) that slides on a stepped reduced diameter region (42) of the rod (4) and has a blind hole (54), and a connecting portion (7). At least one recess (43, 56) is provided in the stepped diameter reduction region (42) of the stepped rod (4) or in the tubular portion (52) of the sleeve (5), The stepped rod (4) is formed as a hollow rod having a through hole (46), and a retractable rod (6) is housed in the through hole (46). The retractable rod (6) is guided through the through hole (46) of the stepped rod (4), and the first end (61) of the retractable rod (6) is connected to the coupling (7), and the second end (62) of the retractable rod (6) is connected to the sleeve (5). By bringing the coupling (7) closer to the sleeve (5), an axial stress is applied to the stepped rod (4), and as a result of the stress, the tubular portion (52) of the sleeve (5) is pressed radially outward. Due to the expansion induced by the outer diameter stress of the tubular portion (52) of the sleeve (5), the gap width (S) of the annular gap (9) is smaller than the gap width (S0). Ｖ A gap sealing device characterized in that the recess (43, 56) is set in the radial region of the recess.

2. The gap seal device according to claim 1, wherein the connecting portion (7) has a blind hole (72) with a female thread (73), the male thread (63) at the first end (61) of the retraction rod (6) is screwed into the female thread (73), and the pressure acting in the axial direction on the retraction rod (6) on the stepped rod (4) which is configured as a hollow rod from the connecting portion (7) is set by rotation of the retraction rod (6) about its longitudinal axis (L).

3. The gap sealing device according to claim 1 or 2, wherein the recess is formed on the inner circumference of the stepped reduced diameter region (42) of the stepped rod (4).

4. The gap seal device according to any one of claims 1 to 3, wherein the sleeve (5) is adjustable in the axial direction relative to the retraction rod (6) with respect to the longitudinal axis (L) of the retraction rod (6).

5. The gap sealing device according to claim 1 or 2, wherein the recess is formed on the inner circumference of the pipe portion (52) of the sleeve (5).

6. The gap sealing device according to claim 3 or 5, characterized in that the recess is formed as an annular recess.

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