WO2015139823A1

WO2015139823A1 - Protective lining for a process fluid-carrying inner surface of a channel of a metal part, metal housing and method for producing said protective lining

Info

Publication number: WO2015139823A1
Application number: PCT/EP2015/000530
Authority: WO
Inventors: Wilfried Drechsler; Eric Stolzenberg
Original assignee: Pfeiffer Chemie-Armaturenbau Gmbh
Priority date: 2014-03-17
Filing date: 2015-03-10
Publication date: 2015-09-24
Also published as: DE102014003856A1; DE102014003856B4

Abstract

The invention relates to a protective lining for a cover surface of a metal part (15) exposed to a process fluid, such as of a metal housing and/or a guide member of a fluid throttle device, a control valve or a ball valve, of a process system, comprising: a full-surface lining layer (11) of lining material resistant to process fluid in order to cover the entire area of the cover surface, wherein the lining layer is profiled to complement the shape of the cover surface, and a reinforcement (3) adapted to the profile of the cover surface is provided, the material of said reinforcement being more resistant to deformation than the lining material.

Description

Protective lining for a process-fluid-carrying internal channel surface of a metal part, metal housing and method for producing the protective lining

The invention relates to a protective lining for a process fluid-carrying channel inner surface of a metal part, such as a metal housing of a fluid throttling device, such as a shut-off device, a control valve or a ball valve, a process plant.

Such a protective lining is disclosed for example in German Utility Model GM 77 07 794. There, the channel inner surface of a so-called ball valve or ball valve is provided with a plate-like plastic layer of polytetrafluoroethylene (PTFE), so that the contact of the metal channel inner surfaces of the ball valve is excluded with aggressive process media of the process plant.

In recent years, the protective lining has been continuously developed by lining thermoplastics such as PFA, the channel-side inner area and / or arranged in the fluid channel functional elements of the fluid throttle device over the entire surface. For the production of the channel inside the fluid throttling device usually a spraying technique is used, in which a mold core is inserted into the housing structure of the fluid throttling device or a mold formwork for the functional member is provided. In the gap defining the gap between the channel inside or the Funktionsorganaußenseite and the respective shape of the plastic at a pressure of about 200 bar and temperatures of about 300 ° C is injected. It has been found that due to the subsequent cooling after the injection process, for example, by cooling water or a suitable cooling fluid, internal stresses arise within the plastic protective linings, depending on the channel to be covered channel side or functional element outer side profile especially at concave profile sections bulging the liner to move away from the surface to be covered. This bulging can significantly limit the operation of the fluid throttle device, because the bulging or contrasting from the metal surface to be covered lining section may not only a lining function, but also additional functions. For example, the lining portion serves on the vertical channel of the auxiliary connection piece of the ball channel according to the German Utility Model GM 77 07 794 as a sealing outer surface for a packing seal, the sealing sleeves are against the lining inner surface in circumferential sealing engagement. If the lining bulges in this sealing surface region, the curved lining section can yield to the cuff pressure due to the lack of support on the channel inner surface, which is communicated to the packing by axially acting leaf springs. It can not be ensured that the sealing function between the ball valve interior and the outside remains ensured at the bulge. The bulging of the lining and the removal of the metal surface to be covered is also to be avoided insofar as in the thereby forming hollow space and space between the lining and the metal surface to be covered diffusing constituents of the process fluid can accumulate in large quantities.

In order to avoid detachment of the protective lining from the metal surface of the valve housing to be covered, it is known per se to increase the coefficient of adhesion coefficient of the channel inner surface by means of roughening. A proven mechanical coupling between the metal surface to be covered and the lining surface is realized by means of a dovetail mold closure, wherein the lining material engages in a circumferential Einknüpfaussparung incorporated in the metal part. Such a dovetail-form closure is shown in the attached Figures 6 and 7, according to which a ball valve except for the two main connection pieces a and b includes the above-mentioned auxiliary connection piece c. The connecting pieces a, b, c are part of a ball valve housing, which is made of metal, such as gray cast iron. In the auxiliary connection pipe c an actuating spindle d is rotatably inserted, which is sealingly supported on a cloth bushing packing f. The channel inner surface of the auxiliary connecting piece c is covered over its entire surface with a lining layer g in order to protect metal surfaces from the process fluid. In order to counteract a lifting of the protective lining, a plurality of dovetail formings h are realized in the course of the channel inner surface, which holds the protective lining g despite a bulging tendency on the channel inner surface of the metal parts. In long-term tests it has been shown that due to the cooling of the lining resulting residual stress cracks can occur at sharp-edged transitions, especially in the dovetail mold closure, in the lining material. This can lead to the loss of the attachment function. lead on the dovetail mold closure, whereby the bulge of the protective lining can spread.

It is an object of the invention to overcome the disadvantages of the prior art, in particular to make the protective lining for process fluid-conducting metal surfaces more durable.

This object is solved by the features of claim 1.

Thereafter, a protective lining for a process fluid exposed cover surface of a metal part, such as a channel inner surface of a metal housing and / or the outer surface of a guide member of a fluid throttling device, such as a shut-off, a control valve or a ball valve, a process plant provided. The protective lining should be as close as possible, close to the cover surface. The full-surface protective lining prevents contact of the most aggressive process fluid with the metallic covering surface. The protective lining has a full-surface lining layer preferably made of plastic, such as a thermoplastic material. For example, PTFE or PFA can be used.

The lining layer is profiled in a shape complementary to the covering surface, so that it can snugly fit against the covering surface, so that cavities between the facing surfaces of the metal part and the protective lining are largely avoided. Preferably, the lining layer is so strong to form that a rigid intrinsically stable structure is formed. The intrinsically stable structure may have a uniform wall thickness of at least 3 mm, preferably 3.5 to> 10 mm. Advantageously, the lining layer is profiled plate-like. According to the invention, a stiffening in the protective lining, which also conforms substantially to the profile of the covering surface, is provided in the protective lining, the material of which being more resistant to deformation than the lining material. Thus, the stiffening, the lining layer and the profile of the covering surface can be at least profile-like and / or profile-identical, wherein dimensional differences depending on the layer position and / or thickness of the stiffening, the lining layer and the covering surface can be present to each other. In particular, the stiffening of the profiled covering surface follows at a distance from it, which is filled by the material of the lining layer and / or can vary or preferably remains substantially constant at least in sections. It who- provided according to the invention two different materials for different functions of the protective lining, namely the lining layer to protect against the aggressive process fluid on the one hand and the stronger stiffening for receiving voltage loads acting on the protective lining, for example due to temperature fluctuations. Preferably, the stiffener is coupled to the liner ply such that internal stresses of the liner ply which would cause it to deform and external load forces from the stiffener are absorbed and compensated. It has been found that with the implementation of a stiffening the protective lining as a unit is formed significantly more rigid deformation, and may have a higher modulus of elasticity. Even at higher loads, significantly lower deformations of the protective lining occur, as a result of which bulging of the protective lining away from the covering surface is avoided even in the case of long-term loads. Stress peaks due to profile jumps, such as dovetail formations, are avoided.

In a preferred embodiment of the invention, the liner ply has a substantially uniform wall thickness of preferably more than 3 mm.

In a preferred embodiment of the invention, the liner ply and the stiffener are coupled to each other to form a forceful end so that forces acting on the protective liner can be absorbed by the stiffener. The lining layer is preferably injection-molded onto the stiffening and / or injected around the stiffening, so that the stiffening is at least partially, in particular completely, embedded in the lining layer. In a preferred embodiment of the invention, an approximately circumferential portion of the stiffener, in particular an edge portion of the stiffener, be free of lining material, because this portion should be in direct abutting contact with the cover surface. Apart from this support surface, preferably all further sections are covered with the lining material in order to provide sufficient adhesion between the reinforcement and the lining layer.

In a further development of the invention, the stiffening comprises a panel profile which is adapted to the covering surface, in particular of metal, such as steel. The plate-like stiffener may comprise a constant plate thickness. Preferably, the plate thickness of the stiffening is smaller than the wall thickness of a particular sleeve-shaped lining layer. In particular, In particular, the plate thickness of the stiffening is less than 50% of the wall thickness of the lining layer.

In a further development of the invention, the stiffening has a plurality of passages for anchoring or clawing the lining layer to the stiffening. The plurality of passages are completely penetrated by the lining material for sufficient anchoring of the liner ply. The lining material may extend from a completely covered with the lining material, the cover surface facing side of the stiffening through the passages to a completely covered with the lining material, facing away from the cover surface side of the stiffening without interruption. In particular, a plurality of uniformly distributed through holes, preferably of the same cross-sectional dimension, may be provided in the stiffening in order to achieve a uniform anchoring of the stiffening to the lining layer.

In a preferred embodiment of the invention, the protective lining, in particular the lining layer and the stiffening, is rotationally symmetrical. Preferably, the protective lining, in particular the lining layer and the stiffening, is cylindrical and / or hemispherical. The stiffener may be provided with a slot extending along the axis of rotational symmetry in order to be radially elastically expanded or compressed in a manner similar to a snap ring.

In a preferred embodiment of the invention, the lining layer is stiffened by means of the stiffening, in particular on the process fluid side concave channel portion of a metal housing part, wherein preferably in the region of a process fluid side convex channel portion, the liner layer may be formed without stiffening.

In a preferred embodiment of the invention, the stiffener is an assembly of a plurality of separate stiffening elements coupled together to form a structure of a formed protective liner through the liner layer. As an assembly aid between the stiffening elements may be narrow coupling webs, which are not or hardly to serve for power transmission between the stiffening elements.

Furthermore, the invention relates to a metal part, such as a metal housing and / or a functional member for a fluid throttle device, such as a shut-off, a control valve or a Ball valve, a process engineering plant. The metal part according to the invention has a covering surface exposed to a process fluid and a protective lining according to the invention covering the covering surface.

Preferably, the lining layer is molded onto the covering surface, wherein the stiffening is at least partially encapsulated during injection molding. Preferably, the stiffener is biased in particular before the gating due to elastic shaping during assembly for exerting a pressing force against the cover surface.

In a further development of the invention, the covering surface is formed with a recess, such as a groove, so that the stiffening element applied to the covering surface is positioned to form the bottom of the recess, forming a particularly annular gap. Preferably, the gap is occupied, for example, by spraying technique for surrounding the stiffening with the lining material. At a circumferential boundary edge of the recess, a positioning shoulder is formed on the cover surface on which the stiffener rests and against which an axial outer edge of the stiffener can abut during assembly.

Furthermore, the invention relates to a method for producing a particular protective lining according to the invention for a process fluid exposed cover surface of a metal part, such as a metal housing and / or a functional organ of Fluiddrossel- device, such as a shut-off, a control valve or a ball valve, a process plant. According to the method, the metal part is provided with the cover surface. Subsequently, a separate stiffener is positioned in a stationary manner on the covering surface to be covered by the protective lining. It is also possible to position several stiffening elements separately. Subsequently, the stiffening with lining material, such as plastic, reshaped, in particular lined or overmolded, so that a Formund raftschluss between the stiffener and the surrounding lining layer is realized.

It is clear that the method according to the invention can be designed such that the protective lining according to the invention and the metal part according to the invention can be produced. Further features, advantages and features of the invention will become apparent from the following description of preferred embodiments of the invention with reference to the accompanying drawings, in which:

1 shows a cross-sectional view of a protective lining according to the invention in a first embodiment, unmounted on the process fluid-carrying metal part.

FIG. 2 is a perspective sectional view of the protective lining of FIG. 1; FIG.

3 is a perspective view of a single stiffening element of a protective lining according to the invention;

4 shows a metal housing part according to the invention of a fluid throttling device with two stiffening elements already mounted before a lining layer is overmolded;

5 shows the metal housing part according to FIG. 5 with a protective lining according to the invention in a further embodiment, in which the stiffening elements are encapsulated with the lining material.

Fig. 3 shows a detail of a stiffening element, which is provided with the reference numeral 1. The stiffening element 1 in Fig. 3 is designed as a slotted cylindrical metal sleeve 3, which comprises an axially extending longitudinal slot 5 for a snap ring-like mounting of the stiffening element 1 to be covered channel inner surface 25, 43.

The cylindrical metal sleeve 3 is provided with uniformly distributed through holes 7, which extend from one of the channel inner surface 25, 43 facing outside 9 toward the side facing away from the channel inner surface 25, 43 inner side 10 therethrough. As can be seen in FIG. 3, the through-holes 7 are arranged in axial rows around the entire circumference of the metal sleeve 3.

It is clear that a stiffening element 1 can also have other circumferential or slotted profiles. When using a stiffening element for a protective lining on a nem functional element of the control valve, such as a valve member, also plate and cup-shaped stiffening element shapes can be used.

It should be understood that the stiffener may also be composed of a plurality of separate stiffening elements, for example, first loosely applied to the channel inner surface 25, 43 and then coupled together to form a structural unit as the liner ply 11 is sprayed around the separate stiffening elements 1 is (see Fig. 1 and 2). The stiffening element may be metal, in particular steel, and is necessarily more resistant to deformation than the material of the lining layer.

For preassembling the stiffening element 1 on the channel inner surface 25, 43, the slotted metal sleeve 3 is compressed resiliently in the radial direction like a snap ring. The slit 5 decreases, and the circumference of the metal shell 3 is reduced. In this way, the metal sleeve 3 can be axially inserted into a correspondingly cylindrical channel inner surface 25, 43 of the metal part 15. The elastic restoring forces of the metal sleeve 3 cause a frictional engagement of edge portions of the outside 9 of the metal sleeve 3 at the respective channel inner surface 25, 43, whereby the metal sleeve 3 rests fixedly against the metal housing part 15 according to a first assembly step.

For a subsequent injection-molding step, a mold core (not shown) is used to internally profile the liner ply 11, and the liner ply 11 is overmolded with plastic around the stiffener member 1 so that all through-holes 7 are penetrated by the liner material and approximately approach the metal shell 3 completely embedded in the lining layer 11 is located. The lining material abuts directly on the metal sleeve 3, so that the occupation of the hole walls, hole edges, side edges of the metal sleeve 3 causes an anchoring or clawing of the lining layer 11 with the stiffening element 1.

The material, such as metal, preferably steel, for the stiffening element 1 is significantly stiffer and more resistant to deformation than the lining material. In this way, the protective lining 13 has a higher modulus of elasticity than a protective lining consisting exclusively of a lining layer 11 of fluid-process-resistant plastic. Loads acting on the protective lining 13, such as internal stress, process forces due to temperature fluctuations, are absorbed by the stiffening element that is more resistant to deformation, so that the lining material of the lining layer 11 is spared. In this way, a functional separation of the protective lining 13 is effected so that mechanical loads are compensated by the stiffening element 1, while process chemical stresses are endured by the lining material.

In Fig. 1 and 2, the stiffening is realized with two separate stiffening elements 1, the metal sleeves 3 have different diameters. In this way, a profiled in the axial direction protective liner 13 can be realized, which may have, for example, a centrally radially projecting shoulder 14. Both stiffening elements 1 are separated from each other on the channel inner surface 25, 43 pre-assembled on the metal housing part and molded in a single manufacturing step with the lining material. In this way, different moduli of elasticity can be realized at respective portions of the one-piece protective lining 13, by correspondingly stiffening elements 1 of different forming strength are used. In FIGS. 1 and 2, it can be seen that the smaller diameter stiffening element 1 has a smaller cross sectional area between the through holes 7 than the larger diameter stiffening element 1.

In order to cover the outer surface 9 of the metal sleeve 3 over the entire surface with the lining material, a cylindrical, radially outward projection 19 or crown can be formed on the outer side of the lining layer 11, which can optionally be finished to form a sealing surface. At least in the region of the outer projection 19, the metal sleeve 3 is covered over its entire surface. Only for the installation of the metal sleeve 3 on the channel inner surface 25, 43 remain axial edges 23, 24 of the respective metal sleeve 3 of lining material unoccupied (Fig. 1, 2), since the axial edge for positioning of the metal sleeve 3 should abut directly against the metal housing part 15 before the injection step ,

In addition, a complete penetration of the through holes 7 is ensured by the outer projection 19, whereby the anchoring and Verkrallungseffekt is optimized.

FIGS. 4 and 5 show a metal part 15 in the form of a metal housing, in particular gray cast iron. The metal part 15 serves to form the housing structure of a fluid throttle device, such as a ball valve, of a process plant. The metal part 15 comprises a connecting piece 17 which extends in the main axial direction Z and has a Mounting flange and a lying perpendicular to Hauptaxialrichtung Z auxiliary connection piece 21, which is designed for receiving an actuating spindle (not shown), which sealed via a cloth bushing packing not shown (as in "f 'in Fig. A, B) against the channel interior of the metal part 15 should be.

As can be seen in FIG. 4, the metal part 15 defines a plurality of sections of channel inner surfaces 25, 43 with different profiles. A substantially cylindrical inner channel surface 25 is formed in the main connecting piece 17. This channel inner surface 25 forms an axially extending Z, circumferential, cylindrical recess 27, the recess bottom 31 is in a constant annular distance to the outside 9 of the metal sleeve 3 to form the outer projection 19. The recess 27 extends in Hauptaxialrichtung Z approximately over the entire longitudinal extent of the metal sleeve 3 and ends in front of the axial edges 23, 24 of the metal sleeve 3 to form positioning stages 35 on which the respective axial edge 23, 24 rests. The positioning stage 37 comprises a stop 39 which projects radially beyond the axial edge 23, 24 and against which the inserted metal sleeve 33 can push for axial fixation. For mounting, the metal sleeve 3 is inserted between the axially opposite stops 39.

Also in the auxiliary connection piece 21, a stiffening element 1 is used as a metal sleeve 3, which has a smaller diameter than the metal sleeve 3 in the main connection piece 17. The metal sleeve 3 bears against the channel inner surface 43, which is likewise formed with a recess 45. The bottom of the recess 45 is located in a ring distance to the outside 9 of the metal sleeve 3 to form the outer projection 19. In order to hold the metal shell 3 in the sub-axial direction N, which is perpendicular to the main axial direction Z, a positioning stage 37 with a stop 47 is also formed on the channel inner surface 43.

Both metal sleeves 3 are compressed like a snap ring, to be pre-assembled at the position shown in Fig. 4. Subsequently, the pre-assembled metal sleeves 3 are encapsulated with the lining material, which is shown in Fig. 5. The passages 7 of the metal sleeves 3 and the annular space between the outside 9 of the metal sleeve 3 and the well bottom are filled. A positive connection between stiffening element 1 and the plastic layer 11 is realized. Furthermore, the inwardly facing channel inner surface 25, 43 of the housing part 15 has a plurality of substantially uniform profiles in dovetail shape, which are identified by the reference numeral 50a to 51e. Preferably, the dovetail profiles have undercuts for anchoring the injected liner ply 11. It can be seen that dovetail mold closures are not performed on the regions where stiffeners 1 are inserted, because the stiffeners prevent the protective liner 13 from bulging up from the channel inner surface 25 to be covered. 43. Dovetail joints or form-fit connections are to be arranged, above all, on convex profile changes 71 of the channel inner surface viewed from the interior of the channel.

It can be seen that the plate thickness of the lining layer 1 1 is significantly greater than the wall thickness of the metal sleeves 3. Preferably, the liner layer 1 1 is twice as strong as the metal sleeve 3. Should occur due to temperature changes stresses in the liner layer 11, these are due the force and form fit by the anchoring of the lining layer 11 received in the perforated metal sleeve 3 without the protective liner 13 would have to deform more.

It should be understood that the stiffening elements 1 can be used on the entire rotationally symmetrical protective lining sections in order to avoid any positive engagement by means of a dovetail mold closure.

The features disclosed in the foregoing description, the figures and the claims may be of importance both individually and in any combination for the realization of the invention in the various embodiments.

List of Reference Numerals a, b Main connecting piece c Secondary connecting piece d Actuating spindle

f cloth bushing package

g plastic layer

Swallowtail attachment

1 stiffening element

3 metal sleeve

5 longitudinal slot

7 through holes

9 outside

10 inside

11 lining position

13 protective lining

14 paragraph

15 metal part

17 main connecting pieces

19 outside approach / crown

21 secondary connections

23, 24 axial edge

25, 43 channel interior surface

27, 45 deepening

31 well bottom

35, 37 positioning stage

39, 47 stop

50a - 51e dovetail profiles

61, 63 plastic inner surface

71 convex sections

N secondary axial direction

Z main axial direction

Claims

claims

A protective lining (13) for a process fluid exposed cover surface of a metal part (15), such as a metal housing and / or a Leitorgangs a Fluiddross- device, such as a shut-off, a control valve or a ball valve, a process plant, comprising: a full-surface lining layer (11) made of process fluid-resistant lining material for covering the entire surface of the cover surface, wherein the lining layer (11) is profiled shape complementary to the covering surface, characterized by a likewise adapted to the profile of the cover surface stiffener (1) whose material is more resistant to deformation than the lining material.

2. Protective liner according to claim 1, characterized in that the lining layer (11) has a substantially uniform wall thickness of preferably more than 3 mm and / or non-positively coupled to the stiffener (1), in particular molded on it and / or the stiffening (1) is encapsulated around, so that in particular the stiffener (1) in the lining layer (1 1) is completely embedded.

3. Protective lining according to claim 1 or 2, characterized in that the stiffener (1) comprises a surface adapted to the cover plate profile in particular of metal, such as steel, and / or constant plate thickness, which is preferably smaller than the wall thickness of the preferably sleeve-shaped lining layer (11 ), in particular less than 50% of the wall thickness of the lining layer (11), and / or a plurality of passages (7) for anchoring the lining layer (1 1) to the stiffener (1), which for anchoring the lining layer (11) completely from the lining material is penetrated, wherein the lining material preferably extends without interruption from a side of the stiffening which is completely covered by the lining material and faces the covering surface through the passages to a side of the stiffening (1) which is completely covered with the lining material and faces away from the covering surface, in particular in particular in the stiffening (1) a plurality of uniformly distributed through holes (7) are preferably provided the same cross-sectional dimension.

4. Protective lining according to one of the preceding claims, characterized in that it (13), preferably the lining layer (11) and the stiffener (1), is rotationally symmetrical / are designed, in particular cylindrical and / or frustoconical, wherein the stiffening with a slit (5) extending along the axis of rotational symmetry, in order to be radially elastically expanded or compressed in a snap-ring manner for assembly.

5. Protective lining according to one of the preceding claims, characterized in that the stiffener (1) in the region of a process fluid side concave channel portion of the liner layer (11) is arranged and / or in the region of a process fluid side convex channel portion, the liner layer (11) is formed without stiffening.

6. Protective lining according to one of the preceding claims, characterized in that the stiffener is an arrangement of a plurality of separate stiffening elements (1), which are coupled to form a structured as a structural unit protective lining (13) by the lining layer (11) to each other.

7. metal part, such as metal housing and / or functional element for a Fluiddrosselvorrich-, such as a shut-off, a control valve or a ball valve, a process plant, comprising: a process fluid exposed cover surface and a cover covering the protective lining (13) according to one of the above Claims.

8. metal part according to claim 7, characterized in that the lining layer (11) is injection molded onto the cover surface and / or the stiffener (1) is biased in particular before the gating due to elastic deformation during assembly for exerting a pressing force against the cover surface.

9. Metal part according to claim 7 or 8, characterized in that the cover surface is formed with a recess (27, 45), such as a groove, so that the on the covering surface applied stiffener (1) to form a gap space to the bottom of the recess (27, 45) is positioned, which is for example by spraying technique for surrounding the stiffener (1) is covered with the lining material, in particular at a peripheral boundary edge of the recess a Positionierabsatz (35 37) is formed on the cover surface, on which the stiffener (1) rests and / or against which an outer edge (23, 24) of the stiffener (1) bears directly contacting during their assembly.

10. A method for producing a particular according to one of the preceding claims 1 to 6 formed protective lining (13) for a process fluid exposed cover surface of a metal part (15), such as a metal housing and / or a functional organ of a fluid throttle device, such as a shut-off, a control valve or a ball valve, a process plant, wherein

a) the metal part (15) is provided with the covering surface;

b) a separate stiffener (1) is fixedly positioned on the covering surface to be occupied by the protective lining (13); and

c) the stiffener (1) with lining material, such as plastic, reshaped, in particular encapsulated, and a positive and frictional connection between the stiffener (1) and the surrounding lining layer (11) is realized.