EP2591260A1

EP2591260A1 - Clamp for fastening components

Info

Publication number: EP2591260A1
Application number: EP11724550.6A
Authority: EP
Inventors: Helmut Hiss; Jochen Caspari
Original assignee: Hydac Accessories GmbH
Current assignee: Hydac Accessories GmbH
Priority date: 2010-07-08
Filing date: 2011-05-27
Publication date: 2013-05-15
Also published as: US8550411B2; WO2012003905A1; DE102010026596A1; US20120006948A1

Abstract

The invention relates to a clamp for fastening components, in particular strand-shaped or linear parts (2), such as pipelines, hoses, or cables, comprising at least one clamp part (3), which by means of an outer contour (4) at least partially defines an accommodating space (5) for accommodating the particular component, wherein at least the one clamp part (3) has a device (6) for minimizing crevice corrosion in the accommodated component. The clamp is characterized in that the device has at least one sacrificial element (7), which is noticeably consumed upon the beginning of crevice corrosion and during continued use of the clamp fastening, and that the particular sacrificial element (7) is placed on the outer contour (4) of the associable clamp part (3) and/or inserted into the associable clamp part as an independent component and at least partially protrudes into the accommodating space (5) and/or bounds said accommodating space.

Description

Hydac Accessories GmbH, Hirschbachstrasse 2, 66280 Sulzbach / Saar Clamp for fixing components

The invention relates to a clamp for attachment of components, in particular of strand-like components, such as pipes, hoses or cables, with at least one clamp member which defines at least partially with an outer contour a receiving space for receiving the respective component, wherein at least the one clamp member means for Minimization of crevice corrosion in the respective recorded component. In electrical or hydraulic systems where hoses or cables and piping are laid on system components, static or dynamic loads (vibrations) can cause damage to the respective string-shaped components. In addition, for reasons of clarity, hoses, pipelines and the like are more systematically to be laid along system parts suitable for this purpose. It is therefore state of the art to mount the said cables and lines by means of clamps, which serve both as spacers and contribute to securing the position. Such clamps basically have means for fixing them to third-party components, for example in the form of spatially separated passage points for the passage of fastening elements. ments, such as screws and the like, wherein the clamp parts individually or in their entirety when fixing the linear elements, for example in the form of hoses or cables, surround them at least partially or along their entire circumference. The element to be fastened, which is regularly linear, is basically fixed in a form-fitting manner within the clamp with the clamp parts. In addition to the above-mentioned passage points for the fasteners describes as a further alternative embodiment, GB 1 224 535 A a clamp on which a latching device is arranged, by means of which the Schell lenkörper in einan- the approximate state while receiving the line-shaped element in a clamping manner to each other can.

In particular, when using the clamps in a corrosive environment, such as the use of electrical or hydraulic systems in the offshore sector, it can even to the use of plastic clamps that serve to secure stainless steel pipes, corrosion on the defined, linear elements, such as the stainless steel pipes due from environmental influences, such as salty air and the like come. Thus, crevice corrosion of metal parts occurs regularly in the presence of a corrosive medium in unfinished bearing gaps, for example formed by overlaps, patched webs and non-welded through joints. The driving force for the crevice corrosion is the concentration difference between the actual gap and the "outer gap area" of the corrosive medium.This difference in concentration results in a potential difference which leads to electrochemical corrosion within the gap or in the vicinity of the gap. Even otherwise stainless CrNi steels can corrode in the cited columns if there is no medium, such as oxygen, to form a protective oxide layer or if it can not form due to mechanical stress. Furthermore, in the state of the art clamps and clamp parts are known, which have a so-called device for minimizing corrosion, wherein the device is formed from a so-called inhibitor, which is introduced into the plastic material of the respective clamp part. Thus, for example, the inhibitor, consisting of ethanolamine and sulfolane, as a carrier by means of pressure impregnation in the plastic material from the outside bring. Furthermore, the pressure impregnation with a so-called gas field inhibitor (naphthenic acid derivative) can likewise be carried out from the outside. A further possibility of using corrosion inhibitors in the absence of gaps is to coat flat clamp surfaces and surfaces with organic coatings containing microcapsules, which penetrate into the surface of the clamp material accordingly. In view of this prior art, the object of the invention is to provide a clamp which is able to effectively prevent corrosion and, in particular, crevice corrosion between it and the male linear element to be accommodated. According to the invention, this object is achieved by a clamp having the features of claim 1 in its entirety.

The peculiarity of the invention accordingly consists in that the clamp has a device for minimizing crevice corrosion to the effect that the device has at least one sacrificial element as an independent component, which gradually consumes the onset of corrosion conditions on the clamp by particular electrolytic material removal. The sacrificial element is placed on the outer contour of the assignable clamp part and / or inserted into it and at least partially projects into the receiving space and / or delimits it. The effect of the clamp according to the invention is found in extensive, scientific lent investigations have been demonstrated and it is surprising for a person of ordinary skill in the field of fastening technology that he can dispense with the use of a relatively inexpensive sacrificial element arrangement on the expensive inhibitor solutions and still achieved a significantly improved corrosion protection, as with the known solutions described above ,

According to the invention, a clamp is thus available which permanently prevents a material attack and a progressive weakening of the material of the relevant component to be fastened with the clamp. The system equipped with clamps according to the invention as a third component is thus permanently protected against operational impairments or a breakdown due to corrosive attack their strand-like components, such as pipes, cables and the like. A high operational safety of the system is also made possible by the clamp according to the invention.

A preferred embodiment of a clamp provides that the sacrificial element is formed in the manner of an electrode, such as a sacrificial anode. The sacrificial anode enables an electron flow in the direction of the line-shaped component or component fastened to the clamp, so that no material removal under corrosive influences of a corresponding environment can take place thereon. In a particularly preferred embodiment of the clamp, at least a part of the clamp has a cup-shaped depression, onto which the sacrificial element according to the invention is placed following the contour of the recess and the contour of the component to be fastened. It may also be advantageous to provide a part of the clamp or the entire clamp with chamber-like cutout areas as part of the outer contour of the clamp into which the respective sacrificial element, preferably with a predeterminable supernatant, can be used, so that insofar as the sacrificial element is also placed as an independent component on the outer contour of the assignable clamp part. In this way, the sacrificial element can be inserted segment-wise and optionally without adhesive within the clamp, which is very easy to assemble before the actual mounting of the clamp on the component to be accommodated begins. The clamp and the sacrificial element used in each case form a suitable for immediate use unit at the intended installation location. In a particularly preferred embodiment, the sacrificial element follows the shell shape of the clamp part and is also not on the edges of the bowl-shaped recess of the clamp over what space is saving. The sacrificial element is formed for the purpose of the largest possible contact with the line-shaped component to be fastened from a foil-like or plate-like, flat blank which, when brought into shape, forms a cup-shaped contour which is fixed stress-free in the corresponding contour of the clamp. The sacrificial element may preferably comprise magnesium and / or tin components and is preferably formed entirely from one of these non-ferrous metals.

The sacrificial element preferably completely clad the bowl-shaped depression in the clamp. It may be connected via an adhesive connection preferably using a hot melt adhesive to the clamp. It may also be advantageous to provide a positive connection in the manner of a clip connection between the sacrificial element and the clamp. The clamp thus forms a ready to install functional unit of clamp body and sacrificial element. The clamp is preferably composed of two half-shell-like equal components. In a particularly preferred embodiment, the two, the clamp-forming equal components are formed as block-like clamping parts, which define a receiving space - preferably in cylindrical form - and form a radial gap between itself and the male component, in which the plate-like sacrificial element can be used as an independent component. It is also possible to provide two sacrificial elements of equal size on each clamping part, which in the mounted state of the clamp and of the component to be fastened completely surround or surround it along its circumference. The block-like clamping parts can have passage points, with the aid of which fixing elements, such as hollow rivets, screws od. Like., Can be guided through the clamp in order to set the same to third components, such as plant parts and the like.

The solution according to the invention is explained in detail below with reference to the drawing. They show in a principal and not to scale representation of Fig.l a frontal front view of the clamp according to the invention in the assembled state;

Fig.l b is a perspective view of the clamp according to the illustration of Fig.l a without fixing elements, wherein the two clamp parts of the better representation are not drawn congruent;

FIG. 2 shows a perspective view of two clamp parts designed as equal components; FIG. a view of another embodiment of clamp members without sacrificial elements; a perspective view of an embodiment of a sacrificial element for the clamp parts according to the illustration of Figure 3; and a plan view of two clamp members with sacrificial elements installed after exposure to corrosive environments for an extended period of time.

In the Fig.la a clamp 1 according to the invention for fastening a formed as CrNi steel pipe component 2 is shown as a component of a hydraulic offshore plant in the closed state in a schematic, not to scale. The clamp 1 consists essentially of injection-molded clamp members 3, formed from a thermoplastic material, here in the form of a polypropylene plastic. The clamp parts 3 are, as shown in FIG. 2, designed as equal components with a substantially rectangular outer planform. The envelope shape of the clamp 1 is thus cube-shaped, wherein, as the Fig.la shows, a receiving space 5 is formed in the form of a hollow cylinder of the two composite clamp parts 3. The receiving space 5 for the component 2 to be fastened is formed in the split state of the clamp 1, as shown in Fig.la, in each clamp member 3 by a semi-cylindrical part or a cup-shaped recess 9. The shell-shaped depressions 9 are formed symmetrically with respect to a longitudinal axis 15 of the clamp 1; However, they could also be asymmetrical to each other and / or formed with different diameter size. Each clamp part 3, as also shown in FIGS. 3 and 5, forms a further embodiment. play for the clamp 1 show, a block with a fictitious parting plane 16, which, as mentioned, is interrupted by the semi-cylindrical recesses 9, wherein the recesses 9 again form the said receiving space 5 in the closed state of the clamp 1.

Viewed in the radial direction to the longitudinal axis 15 of the clamp 1, the clamp parts 3 are formed of plastic with recesses 9, define their radii an excess in relation to the diameter D of the component 2 to be fastened. The outer contour 4 of the recesses 9 seen in the direction of the component to be fastened 2 are shown in the embodiments of FIGS. 1 a to 2 over the entire surface. As a result, there is a total gap between the depressions 9 of the clamp parts 3 and the outside of the line-shaped component 2 to be fastened, which can be filled with a device 6 for minimizing corrosion, in particular crevice corrosion, on the component 2 to be fastened. In the embodiments according to FIGS. 1 a to 2, the pertinent device 6 is formed by a metallic sacrificial element 7 in the form of a plate-like zinc sacrificial anode 8 introduced into the shape of the recesses 9. The sacrificial element 7 thus forms a, in their wall thickness uniform half-shell with semicircular cross section for each clamp part 3.

As particularly shown in FIGS. 1 b and 2 show further, the sacrificial element 7 is arranged both flush with the outer contour of the clamp 1 and the fictitious parting plane 16. The sacrificial element 7 is in the embodiment shown with an adhesive, in particular in the form of a hot melt adhesive, fixed non-positively on the respective clamp member 3. As a result, in total in the mounted state, a full-surface contact of the sacrificial element 7 to the component 2 to be fastened, for example in the form of a stainless steel pressure medium line of a hydraulic system, possible. Thus, throughout the investment area, the Schelle le 1 provided on the component to be fastened 2 and thus in the entire, endangered by the effects of crevice corrosion region of the component 2 to be determined a sacrificial element 7, which can prevent any corrosive removal of the component to be fastened 2. The clamp 1 forms due to their dimensions in relation to the component 2 to be fastened together with the sacrificial element 7, a clamping part 1 1 for receiving the component 2 to be fastened.

For this purpose, each clamp member 3 viewed in the radial direction to the longitudinal axis 15 between the respective recesses 9 and the radial side surfaces of each clamp member 3 on both sides and perpendicular to the respective fictitious parting plane 16 passed passage points 13 for individual fixing elements 14 of the clamp 1. The passage points 13 are preferably formed as cylindrical bores and allow the implementation of machine screws, which are preferably provided with a hexagonal head (see Fig.l a). The fixing elements 14 combine the extent of the function of the clamping of the stranded or linear component 2 in the receiving space 5 of the clamp and the determination of the clamp parts 3 to each other. In addition, the fixing elements 14 can serve for fixing the clamp 1 to a non-illustrated third or plant component.

In Figure 3, a further advantageous embodiment of the clamp 1 according to the invention is shown. The outer contour 4 in the region of the recesses 9 is formed as a chamber-like cutout region 10 in the case of the two clamp parts 3 shown. The pertinent outer contour is fanned out for this purpose in a total of five ribs 1 7, whereby the contact surface of the clamp parts 3 is reduced to the component to be fastened 2, which can lead to higher clamping forces compared to the full-surface embodiment shown in Figures 1 and 2 , The ribs 1 7 essentially have a constant wall thickness over their entire side projection area. In addition to the Klemmkrafterhöhung beyond there is the possibility, disc-like sacrificial elements 7, as shown in a view in Figure 4, to push between the chamber-like cutout areas 10 so that in turn the Opferele- elements are placed on the outer contour of the assignable clamp part 3. As a result, a strip-like installation of the sacrificial elements 7 on the component 2 to be fastened can be achieved. The ribs 17 have the same free side surface shape as that shown in Figure 4 in a perspective view disc-shaped sacrificial element 7. The disc-shaped sacrificial elements 7 have over its entire side surface viewed on a consistent material thickness. The material thickness of these sacrificial elements 7 is chosen in particular such that they can be pushed with a defined bias into the chamber-like cut-out regions 10 of the clamp 1, so as to be fixed captive in the chamber-like cut areas 10. You can be exchanged for a defined material removal at their, the clamp to be fastened with the component 2 facing end face. The clamp 1 itself can be preserved. 5 illustrates in this context the optical state of the sacrificial elements 7 after a corrosive attack over a longer period of use. The material exchange of the sacrificial element 7 with the attacking electrolyte causes a surface area of the active surface of the sacrificial elements 7 with the component to be fastened 2, for example in the form of a stainless steel tube. Instead of a subsequent introduction of sacrificial elements 7 in the respective clamp member 3 by pressing or gluing the sacrificial elements 7 in the chamber-like cutout areas 10 can also be an arrangement of the sacrificial elements 7 in the respective injection mold before making the clamp parts 3 itself. The sacrificial elements 7 represent disposable cores in the respective injection mold, which are entrained during demolding of the clamp parts 3. The sacrificial elements 7 can thereby be suitable, preferably lateral undercut areas (not shown), which allow a partial encapsulation of the sacrificial elements 7 with plastic or other clamp material. The clamp 1 may also be formed in one piece in the sense of a single clamp member 3, in which case preferably the wrap angle of the receiving space 5 to the component to be fastened 2 is greater than 180 °. It may also be advantageous to connect two clamp parts 3 via a hinge, in particular a film hinge, so that then a total of a one-piece clamp 1 (not shown) can be formed. Instead of the described hotmelt adhesive, a special adhesive with a release strip may alternatively be used, which is specially designed for polypropylene with a low-energy surface in cooperation with the zinc surface.

Claims

P a t e n t a n s p r u c h e

Clamp for fastening components, especially strand-shaped or linear components

(2), such as pipelines, hoses or cables, with at least one clamp part (3), which at least partially delimits a receiving space (5) with an outer contour (4) for receiving the respective component, at least the one clamp part (3) being a device (6) for minimizing crevice corrosion in the respective component, characterized in that the device has at least one sacrificial element (7), which becomes increasingly worn out as crevice corrosion sets in and the duration of use of the clamp fastening increases, and that the respective sacrificial element (7) is placed as an independent component on the outer contour (4) of the assignable clamp part (3) and/or introduced into it and at least partially protrudes into the receiving space (5) and/or delimits it.

Clamp according to claim 1, characterized in that the sacrificial element (7) is designed in the form of an electrode, in particular in the form of a sacrificial anode (8).

Clamp according to one of the preceding claims, characterized in that the clamp part (3) has a bowl-shaped recess (9) onto which the respective sacrificial element (7) is placed and/or that the clamp part

(3) has chamber-like cutout areas (10) as part of the outer contour (4), into which the respective sacrificial element (7) is inserted, preferably with a projection.

4. Clamp according to one of the preceding claims, characterized in that the respective sacrificial element (7) has the shell shape of the Clamp part (3) follows and is accommodated in the recess without protruding relative to the edge-side outer contour of the clamp part (3).

Clamp according to one of the preceding claims, characterized in that the sacrificial element (7) is formed from a film or plate-like flat blank which, when shaped, forms a bowl-shaped contour which follows the recess (9) in the assignable clamp parts (3). .

6. Clamp according to one of the preceding claims, characterized in that the sacrificial element (7) has magnesium and / or zinc components, preferably is constructed entirely from at least one of these materials.

7. Clamp according to one of the preceding claims, characterized in that the respective cup-shaped sacrificial element (7) completely lines the cup-shaped recess (9) in the clamp part (3).

8. Clamp according to one of the preceding claims, characterized in that the sacrificial element (7) is firmly connected to the associated clamp part (3) via an adhesive connection, preferably by means of a hot melt adhesive.

9. Clamp according to one of the preceding claims, characterized in that the clamp parts (3) together with the associated sacrificial elements (7) are designed as identical components and that preferably two clamp parts (3) are designed in the manner of block-like clamping parts (1 1). limit the receiving space (5), and that the assigned sacrificial element (7) is inserted in the gap (12) between the component to be received and the respective clamping part (1 1).

10. Clamp according to one of the preceding claims, characterized in that the block-like clamping parts (1 1) are formed, in particular injection molded, from a plastic material, which have passage points (13) outside the receiving space (5) which are subject to the engagement of fixing elements, such as screws or the like, serve to clamp the clamp parts (3) together.