EP0122591A2 - Sealing device for the annular space between a container wall and the floating roof of a large storage container - Google Patents

Abstract

A sealing assembly for a large tank having a generally vertical tank wall and a movable floating cover for sealing an annular gap therebetween to include an annular sealing element adapted to be pressed against the tank wall in sliding sealing engagement therewith and a plurality of spring elements fastened between the floating cover and the annular seal to apply a spring tension tending to press the annular seal against the wall, with a sealing blanket being provided which extends completely around the annular gap between the outer sealing element and the floating cover. The spring elements are composed of U-shaped spring stirrups fastened with a web end at the outer border of the floating cover and including a free spring web with whose end the outer sealing element is rigidly connected. The free spring web is supported with the sealing element and a second contact point at the tank wall with the contact point being spaced away from the sealing element in the vertical direction so that during all movement of the floating cover, the reaction forces of the tank wall acting at the contact points of the free spring webs will constantly hold the free spring webs in an upright position.

Description

The invention relates to a device for sealing the annular gap between the vertical container wall and the floating cover of a large-capacity container, in particular a floating roof tank or a fixed roof tank with an internal floating cover, consisting of a plurality of spring elements fastened at regular intervals next to one another on the circumference of the floating cover, which bridge the annular gap under spring tension and press with its free ends an annularly closed, outer sealing element against the container wall, the annular gap being closed by a sealing apron which runs around the entire annular gap between the outer sealing element and the floating cover.

Such annular gap seals are mainly used for the storage of volatile, liquid refinery products and chemicals to avoid evaporation losses and the accumulation of dangerous vapors. The annular gap between the vertical tank wall and floating ceiling required for the vertical movement of the floating cover must be closed by a sealing system that is as elastic as possible, which is able to compensate for operational changes in the annular gap width as well as severe out-of-roundness and bulges in the tank wall and thereby the escape of product vapors or the intrusion to prevent rainwater as much as possible.

Another important task of the annular gap seal is to ensure that the free-floating cover is adequately centered, which is to ensure trouble-free vertical movement without local overloading or tilting.

Ideally, the annular gap seal should be able to exert a uniformly strong centering effect over the entire circumference of the tank, bridge extreme local deviations in the annular gap width with the aid of sufficient spring travel, and slide as smoothly as possible and with little wear and tear over sharp unevenness in the tank wall.

In practice, one tries to meet these complex requirements by attaching an elastic sealing system to the outer edge of the floating cover, which is adapted to the respective annular gap width by spring forces (DE-AS 23 58 636), by gravity (Bulletin No. 3200 from 1976 by the Chicago Bridge & Iron Company), by internal tension (US Pat. No. 3,795,339) or by hydraulic forces (US Pat. No. 4,773,291) and the gap by a circumferential flexible sealing apron or an elastic filled with liquid or plastic foam Hose closes.

Annular gap seals for floating roof tanks are today usually divided into a primary seal and a secondary seal, with the primary seal facing the stock product being intended to retain the majority of the product vapors and the secondary seal directed against the atmosphere in addition to improving the overall sealing effect especially to prevent the ingress of rainwater. In contrast, annular gap seals for indoor floating ceilings in fixed roof tanks only have the task of limiting product emissions.

The following basic designs are known among the newer secondary seals for floating roof tanks: spring-pressed lip seals (US Pat. No. 4,116,358), spring-reinforced rubber aprons (DE-OS 28 32 978), lip seals made of polyurethane elastomer (publication EKT 0028-3-79 from Elastogran) ), resiliently pressed foam pads with abrasion-resistant covering (own patent application P 31 45 753.3) as well as resiliently pressed, elastic packings with water-wiping effect (own patent application P 32 02 278.6).

Secondary seals in the form of lip seals with spring legs directed at an angle to the tank wall, as well as spring-reinforced rubber aprons or lip seals that bridge the annular gap with elastic deflection, are relatively easily pulled down by horizontally running sliding obstacles and cannot hold back the precipitation falling into the annular gap in this position.

The older, previously unpublished patent application (P 31 45 753.3) describes a secondary seal with a voluminous and rounded sealing element and spring legs running almost vertically and close to the tank wall. With this construction, the danger of turning inside out is eliminated.

Tank operators' demand for secondary seals With a particularly high sealing effect against the rain that runs down the inside wall of the tank during driving rain, new sealing elements have been developed. In the further, previously unpublished application (P 32 02 278.6), a sealing element is described which is able to remove the water film running down the inner wall of the tank with high efficiency from the tank wall. However, the extremely good wiping action can only be guaranteed if the sealing element described always keeps its upright position on the tank wall.

The wiper packing, which is pressed elastically against the inner wall of the tank by spring force, must not perform any tilting movements despite the operational change in the annular gap width and the effect of frictional forces and sliding obstacles, and should always rest on the tank wall with its full working surface and sufficient contact pressure. The known pressure and guide systems do not meet these requirements. Furthermore, the strong change in the contact forces and the angular position to the tank wall causes increased wear of each sealing element due to locally excessive stress, which often causes early failure of the secondary seal.

Below are two other major disadvantages known ter secondary seals. The constructions explained so far require a certain minimum height above half of the upper edge of the floating roof, which is dependent on the width of the annular gap, the friction forces given during operation and the rigidity of the respective spring and guide elements. The effective height of the secondary seal above the upper edge of the floating roof means each lost tank space and should therefore be limited if possible. Furthermore, a defined amount of foaming above the upper edge of the sealing system is usually required for fire fighting, which must be increased accordingly with increasing height of the secondary seal.

• - Primärdichtung und Sekundärdichtung sollen möglichst durch separaten Anschluß an das Schwimmdach in ihrer Wirkund voneinander unabhängig sein.
• - Das Dichtsystem soll ein geringes Gewicht haben und geringe Reibungskräfte verursachen.
• - Die Sekundärdichtung soll so niedrig als möglich angeordnet werden können.
• - Die Primärdichtung soll möglichst mit einem abdichtenden Element in das Lagerprodukt eintauchen und einen geringen Dampfraum bilden.
• - Die gesamte Abdichtung soll eine gute Zentrierwirkung auf das Schwimmdach ausüben, dabei jedoch leicht über Unebenheiten hinweggleiten können und geringen Verschleiß haben.
• - Eine Erhöhung der Zentrierwirkung, z.B. durch Verengung des Ringspaltes, soll nicht automatisch eine Vergrößerung der Anpreßkräfte gegen die Dichtelemente bewirken.

With regard to a common and simplifying construction of the primary seal and secondary seal, the following further requirements arise:

• - The primary seal and secondary seal should, if possible, be independent of each other by separate connection to the floating roof.
• - The sealing system should be light in weight and cause low frictional forces.
• - The secondary seal should be as low as possible.
• - The primary seal should, if possible, be immersed in the bearing product with a sealing element and form a small vapor space.
• - The entire seal should have a good centering effect on the floating roof, but it should be able to slide easily over bumps and have little wear.
• - An increase in the centering effect, for example by narrowing the annular gap, should not automatically result in an increase in the contact forces against the sealing elements.

In a known annular gap seal of the type described at the outset (DE-AS 23 58 636), slender, V-shaped spring legs spread apart upwards and downwards against the tank wall are used to press on the outer sealing elements for the primary seal and secondary seal. The attachment of the V-shaped pressure spring and the primary sealing apron can only be done on the vertical side wall of the floating cover. This is generally undesirable because the holes required for this can cause leaks, as a result of which liquids or vapors of the bearing product can penetrate into the cavity of the floating body. In addition, the relatively narrow outer sealing element with a thin line of contact and only point pressure by the ends of the spring legs cannot produce a good sealing effect. Furthermore, the spring arms directed towards the tank wall at an acute angle with stretched legs and a narrow sealing element can hook up and tip over relatively easily despite the large structural height. The sliding brackets pulled over the outer sealing elements when this sealing system is later implemented considerably reduce the sealing effect. The water film running down the tank wall during driving rain cannot be wiped off by this design of the outer sealing elements.

If the gap is narrowed due to operation, the spring forces and thus the contact forces of the sealing elements increase too much and lead to premature wear of the sealing elements. The contact height of the sealing elements changes with the gap width. This is particularly disadvantageous for the primary side of the seal, since the length and fixation of the primary leg must be determined according to the smallest gap width to be expected and taking into account different immersion depths of the floating cover. The primary seal must not yet be immersed in the stock product. At the locations of medium and large gap widths, the primary seal then lies too high on the tank wall, as a result of which the vapor space below the primary seal is further enlarged, which is undesirable. With the unfavorable sealing effect of these sealing elements, large amounts of Pro Duct vapors escape into the free space between the primary apron and the secondary apron and represent a large vapor reservoir for the emissions at the secondary seal. The secondary seal reaches an excessive height due to the straight and acute angled spring legs against the tank wall.

In the older, previously unpublished patent application by the inventor (P 31 45 753.3), the annular gap sealing of an internal floating cover is described. Here, an elastic sealing element is pressed against the tank wall by spring arms directed downward against the tank wall. This design is only possible if there is a sufficient height difference between the top edge of the floating blanket and the product level.

In the case of lightweight indoor floating ceilings, e.g. made of aluminum or plastic, there is often only a small height available for dimensioning the annular gap seal. Furthermore, with indoor floating ceilings, care must be taken to ensure that only low frictional forces are exerted by the seal, since these constructions have considerably smaller buoyancy forces.

In a further known seal (DE-AS 11 36 276) U-shaped resilient pressure members are provided, which are attached to the outer circumference of the floating roof on the one hand and, on the other hand, pivotally engage sliding shoes which are supported by the resilient pressure members while simultaneously centering the floating roof against the inner wall of the Container are pressed. Here, ring-shaped sealing elements with sharp-edged and stiff profiles are additionally attached to the slide shoes. When hitting sliding obstacles on the tank wall, the sharp-edged seals hook elements firmly attached to the tank wall and the U-shaped pressure elements, which are not limited in their deflection and can be rotated, are subjected to extreme loads and possibly deformed. The pressure elements are designed to be very robust due to the strong vertical forces, which means that when the gap narrows, the forces acting directly on the sealing elements increase inadmissibly. Due to the poor sliding properties of this device, in connection with inadmissibly increasing spring forces, there is a risk that the seal on strong sliding obstacles (horizontal weld seam) hooks so strongly that the entire floating roof is tilted and stuck.

The invention has for its object to provide a device for sealing the annular gap with improved pressure device with simultaneous spring, support and guiding properties, which can be used both with individual primary or secondary seals on floating roof tanks, or on the sealing of an internal floating ceiling, or but can be used in a suitable manner for combined primary-secondary seals and meets the aforementioned requirements.

Starting from the generic type mentioned, this object is achieved in that in a known manner (DE-AS 11 36 276) made from narrow strips, U-shaped spring clips with one leg end are attached to the outer edge of the floating cover, that the free Spring leg, with the end of which the outer sealing element is rigidly connected, is supported with the sealing element and a second contact point on the tank wall, which is remote in the vertical direction, so that with all movements of the floating cover the contact points of the free one Spring leg attacking reaction forces of the tank wall always keep the free spring leg in a constantly upright position.

• - Der U-förmige Federbügel kann an der Tankwand nicht festhaken und umkippen; das abdichtende Element bleibt stets in seiner vorgegebenen aufrechten Stellung.
• - Die wirksame Bauhöhe der Sekundärdichtung kann auf das erforderliche Mindestmaß zur Ableitung der Niederschläge begrenzt werden.
• - Das abdichtende Element bleibt immer in der gleichen Höhenlage.
• - Der U-förmige Federbügel kann große Änderungen der Spaltbreite ausgleichen, ohne große Änderung der Federkräfte.
• - Ein erheblicher Teil der Federkräfte wird allein zur Zentrierung der schwimmenden Abdeckung eingesetzt; der Verschleiß der Dichtelemente bleibt damit wegen schonender Andrückung begrenzt.
• - Die an der Tankwand gleitenden Federbügel bewirken eine zusätzliche Erdung der schwimmenden Abdeckung.
• - Die Gesamtvorrichtung besitzt an der Tankwand gute Gleiteigenschaften.

The annular gap seal according to the invention has the following advantages:

• - The U-shaped spring clip cannot hook onto the tank wall and tip over; the sealing element always remains in its predetermined upright position.
• - The effective height of the secondary seal can be limited to the minimum required to discharge the rain.
• - The sealing element always remains at the same altitude.
• - The U-shaped spring clip can compensate for large changes in the gap width without a large change in the spring forces.
• - A significant part of the spring force is used solely to center the floating cover; the wear of the sealing elements remains limited due to gentle pressure.
• - The spring clips sliding on the tank wall provide additional grounding for the floating cover.
• - The overall device has good sliding properties on the tank wall.

Further advantageous and expedient features of the invention emerge from the subclaims 2 to 14 relating to the developments of the invention.

• Fig. 1 eine perspektivische Schnittansicht der Sekundärdichtung an einem Schwimmdachtank mit einem wasserabstreifenden Dichtelement,
• Fig. 2 bis 5 verschiedene Schnitte durch die Sekundärdichtung gemäß Fig. 1 zur Illustration der Wirkungsweise derselben,
• Fig. 6 einen Schnitt durch eine Sekundärdichtung eines Schwimmdachtanks, bei anderer Ausbildung und Anbringung des Dichtelements,
• Fig. 7 einen Schnitt durch eine Sekundärdichtung eines Schwimmdachtanks, mit einem wasserabstreifenden Dichtelement, konstruktiv verbunden mit einer herkömmlichen Primärdichtung,
• Fig. 8 einen Schnitt durch eine gemeinsame Konstruktion für Primärdichtung und Sekundärdichtung an einem Schwimmdachtank,
• Fig. 9 einen Schnitt durch eine Ringspaltabdichtung - für die Innenschwimmdecke eines Festdachtanks,
• Fig. 10 einen Schnitt durch eine weitere Ausführungsform einer gemeinsamen Konstruktion für Primärdichtung und Sekundärdichtung an einem Schwimmdachtank und
• Fig. 11 eine Schnitteinzelheit insbesondere der in
• Fig. 10 gezeigten Konstruktion.

Further details of the invention are explained in more detail below with reference to the drawings illustrating the exemplary embodiments. It shows:

• 1 is a perspective sectional view of the secondary seal on a floating roof tank with a water-stripping sealing element,
• 2 to 5 different sections through the secondary seal of FIG. 1 to illustrate the operation of the same,
• 6 shows a section through a secondary seal of a floating roof tank, with a different design and attachment of the sealing element,
• 7 shows a section through a secondary seal of a floating roof tank, with a water-stripping sealing element, structurally connected with a conventional primary seal,
• 8 shows a section through a common construction for primary seal and secondary seal on a floating roof tank,
• 9 shows a section through an annular gap seal - for the inner floating ceiling of a fixed roof tank,
• Fig. 10 is a section through a further embodiment of a common construction for primary seal and secondary seal on a floating roof tank and
• 11 is a sectional detail, in particular that of FIG
• Fig. 10 construction shown.

1 shows the vertical container wall 1 of a floating roof tank, which bears the annular gap seal, generally designated by the reference number 2, which bridges the annular gap 3 between the container wall 1 and the floating roof 4. The annular gap seal 2 is used above a conventional primary seal, not shown. U-shaped spring clips 6 are fastened to the horizontally inwardly directed flange 5 of the floating roof 4 by means of screws 7 and with the interposition of terminal strips 8. The free legs 6a of the spring clip 6 are fastened by means of screws 9 to flanges 10 of C-shaped receiving profile pieces 11 directed vertically upwards, about two to four spring clips 6 being connected to a receiving profile piece 11. The receiving profile pieces 11, which are open towards the tank wall 1, press a water-stripping sealing element 12 against the tank wall 1 almost without gaps.

Extension arms 6b of the free spring legs 6a, as well as the sealing apron 17 which runs endlessly around the entire annular gap, are fastened to a second, vertically downward-directed flange 13 of the receiving profile pieces 11 by means of clamping strips 14 and screws 15. The C-shaped receiving profile pieces 11 are perforated at 16 on the back. Short skids 18 are attached in the upper area of the free spring legs 6a.

In accordance with the respective vertical movement of the floating roof 4, the pressing forces of the spring clips 6 are distributed over the sealing element 12 and the vertical extreme points of the free spring legs 6a to the tank wall, formed by the extension arms 6b and the skids 18. The precipitates running down the tank wall 1 are absorbed by the sealing element 12_ and released at the perforation 16 of the receiving profile pieces 1 _" 1. From here, the precipitates are discharged via the circumferential sealing apron 17 derived to the floating roof 4.

The U-shaped spring clips 6 are made from narrow strips of stainless spring steel. The extension arms 6b of the free spring legs 6a are made of non-sparking metal (e.g. brass) and are V-shaped, the legs 6c, which are led back at an angle upwards, support the circumferential sealing skirt 17 when the annular gap 3 becomes narrower, so that the stripped from the tank wall 1 Water cannot be collected in large quantities on the sealing apron 17. The skids 18 attached to the free spring legs 6a are also made of non-sparking metal.

The mode of operation of the U-shaped spring clip 6 can be seen from the schematic FIGS. 2 to 5. FIG. 2 shows the shape of a spring clip with an extremely wide gap 3, FIG. 3 with an extremely narrow gap 3. FIG. 4 shows the position of the spring clip when the floating roof 4 moves downward. The frictional force that arises between the sealing element 12 and the tank wall 1 causes the U-shaped spring clip to expand slightly. As a result, the lower end of the free spring leg 6b is pressed against the tank wall, as a result of which the contact force between the tank wall and the sealing element is reduced and a further spreading of the spring clip is prevented.

5 shows the position of the spring clip when the floating roof moves upwards. The friction between the tank wall 1 and the sealing element 12 causes the spring clip to be compressed. The upper end of the free spring leg 6a comes into contact with the tank wall and reduces the contact forces against the sealing element. As a result, the frictional forces between the tank wall and the sealing element are reduced and further compression of the spring clip is prevented.

The sealing element fastened to the free spring leg 6a undergoes only a slight change in position with all movements of the floating roof relative to the tank wall. The effect of the sealing element is not affected by this. 2 to 5, the different directions of movement of the floating roof 4 are indicated by corresponding arrows.

6 shows the secondary seal 2 'of a floating roof tank with a vapor-tight, elastic sealing element 12', which is primarily intended to limit the product emission. The primary seal underneath is not shown. Comparable components are labeled with the reference numbers used for Fig.1, but are provided with an index line.

The sealing element 12 'running around the entire annular gap 3' is pressed almost completely against the tank wall T 'by individual, C-shaped receiving profile pieces 11'. The free spring legs 6a 'and their downward extension arms 6b' are fastened by screws 9 'and 15' to horizontal legs of the C-shaped receiving profile pieces 11 ', about two to four spring clips 6' each being connected to a receiving profile piece 11 ' .

The circumferential sealing apron 17 'is fastened to the lower leg of the receiving profile pieces 11' by means of clamping strips 14 'and screws 15'. The reaction forces of the tank wall 1 'acting on the vertical extreme points of the free spring legs 6a' and 6b 'keep the sealing element 12 ¹ , which is provided with a plurality of sealing lips one above the other, always in a constantly upright position.

7 shows the construction of a secondary seal 2 "with a water-stripping sealing element 12" in conjunction with a conventional primary seal 19. Comparable components are designated with the reference numbers used for FIG. 1, which, however, are provided with two index lines. The U-shaped spring clips 6 "are fastened together with the sealing apron 22 of the primary seal 19 to the horizontal flange 5" of the floating roof 4 "by means of angled clamping strips 8" and screws 7 ". The sealing apron 17" of the secondary seal 2 "is on the one hand with the lower flange 13 "of the C-shaped receiving profile pieces 11" and, on the other hand, are fastened together with the sealing apron 22 of the primary seal 19 to the upper end of the sliding plates 23 by means of clamping strips 20 and screws 21. The sliding plates 23 of the primary seal 19 can be moved horizontally by means of articulated scissors 24 with the outer edge of the floating roof 4 "connected. Each about two to four spring clips 6 "are connected to a receiving profile piece 11".

The free spring legs 6a "resting on the tank wall 1" have no extension underneath the receiving profile pieces 11 ". When the floating roof 4" moves downward, the friction between the tank wall 1 "and the seal stretches element 12 "the sealing apron 17" and prevents the spring clips 6 "from bending open further. When the floating roof 4" moves upwards, the upper part of the free spring legs 6a "prevents the spring clips 6" from being compressed further by the sliding skids 18 "against the tank wall due to reduced frictional forces The water discharged from the tank wall 1 "through the water-stripping sealing element 12" runs via the sealing apron 22 of the primary seal 19 onto the floating roof 4 ". The height of the sealing skirt 17 "is advantageously dimensioned such that the secondary seal 2" always has unimpeded contact with the tank wall T "even if the primary seal 19 is not adapted to the tank wall t", the sealing element 12 "simultaneously with respect to the height of the floating roof 4" comes into contact with the tank wall 1 "as low as possible.

8 shows the common construction of a primary seal 19 and a secondary seal 2 of a floating roof tank. Components comparable to the secondary seal shown in FIG. 1 are identified by the same reference numbers. The sealing apron 17 and the spring clip 6 of the secondary seal 2 are fastened by means of screws 7 and clamping strips 8 to the flange 5 of the floating roof 4 directed horizontally towards the middle of the tank. On the free spring legs 6a of the spring clip 6, short mounting profile pieces 11 are screwed onto the flanges 10, which are directed approximately vertically upwards, by means of screws 9 and press a water-stripping sealing element 12 against the tank wall 1. Each about two to four spring clips 6 are connected to a mounting profile piece 11 .

At the upper end of the side wall 4a of the floating roof 4 are resilient extension arms 21 of the primary seal 19 fastened by means of screws 20. At the free lower end of each extension arm 21, a U-shaped spring clip 22 and a further one-arm spring clip 23 are fastened by means of screw connections 24. At the upper end of a spring leg 22a directed towards the tank wall 1, a sealing apron 30 is screwed to a separate plunge band 31 welded at 32 using screws 25 and clamping strips 26 on vertically downward flanges 27 of short receiving profile pieces 28. Extension arms 22b of the spring legs 22a are attached to the upper, vertically directed flanges 29 of the receiving profile pieces 28 by means of screws 35, which are designed like runners. Each about two to four spring clips 22 are connected to a receiving profile piece 28.

The sealing apron 30 of the primary seal 19 is continued after fastening below the receiving profile pieces 28 by means of a connecting apron 33 around the primary seal 19 and on the lower, vertical flanges 13 of the receiving profile pieces 11 of the secondary seal 2 together with the skid-like extension arms 6b of the spring legs 6a below Use of terminal strips 14 and screws 15 clamped gas-tight. In the receiving profile pieces 28, an elastic sealing element 34 is held non-positively and without gaps along the tank circumference. The sealing apron 30 is connected in a gas-tight manner to the elastic sealing element 34 by means of the welded-on, separate immersion tape 31. The vapor space between the side wall 4a of the floating roof 4, the sealing apron 30, the immersion tape 31 and the product level 36 is hereby closed in an absolutely gas-tight manner. The connecting apron 33 between the primary seal 19 and the secondary Seal 2 creates a large gas-free space between the two sealing systems and forms a load-resistant connection between the primary seal and the secondary seal.

Since the U-shaped spring clips of the primary seal and the secondary seal are directed towards each other and these spring clips have less sliding resistance when the floating roof moves vertically in the direction of the spring apex, the connecting apron 33, which can withstand tensile loads, is a safety element in the event of sliding problems with one of the two seals. The connecting apron 33 thus has the same effect as the extension arms 6b and 22b of the spring legs 6a and 22a resting on the tank wall and can replace them if necessary. The spring clips 23 support the spring forces of the spring clips 22 and of the extension arms 21.

The extension arms 21 can be made of normal steel due to their small angle change. The spring clips 22, 23 and 6 are advantageously made of stainless spring steel, the receiving profile pieces 28 and 11 made of stainless steel. The skids 37 and 18 attached to the spring clips 22 and 6, as well as the extension arms 22b and 6b of the spring legs 22a and 6a are made of non-sparking metal. The sealing aprons 30, 31, 33 and 17 are provided from appropriately product and weather-resistant plastics with fabric reinforcement. The sealing elements 34 and 12 must also be sufficiently resistant to the frictional forces on the tank wall.

The primary seal is advantageously to be dimensioned such that the sealing element 34 is immersed deeply in the floating roof 4, just above the liquid level 36 completes. The secondary seal is advantageously dimensioned such that the sealing element 12 abuts the tank wall 1 at the lowest possible height above the floating roof 4, so that the water stripped from the tank wall 1 can just be drained off to the floating roof.

9 shows the annular gap seal 202 of an internal floating cover 204 with an extremely low overall height. The sealing apron 217 which runs around the entire annular gap 203 and the narrow, U-shaped spring clips 206 are fastened to the outer upper edge 205 of the inner floating cover 204 by means of clamping brackets 208 and screws 207. Contact strips 218 are riveted to 219 on the free legs 206a of the spring clip 206 which bear against the tank wall 201. The spring clips 206 are immersed in the stock product after being attached to the inner floating cover 204. The free spring legs 206a are bent away from the tank wall 201 above the product level 220 and are screwed to the receiving profile pieces 211 by means of clamping strips 210 and screws 209. Foam elements 212 are positively held in the C-shaped receiving profile pieces 211. The outer part 217a of the sealing apron 217 is wrapped around the receiving profile piece 211 and the foam elements 212, so that a completely closed outer sealing body is produced. On the upper leg of the receiving profile pieces 211, the receiving profile pieces 211, sealing apron 217 and the extension arms 206b of the free spring legs 206a are firmly connected by clamping strips 214 and screws 215. The contact strips 218 and the extension arms 206b of the free spring legs 206a are made of non-sparking metal. _As' material for the spring clip 206 stainless spring band steel is advantageously used. With vertical movement of the Inner floating cover 204, the tilting movements of the annular gap seal 202 caused by friction between the tank wall 201 and the sealing apron 217a are limited by contact of the vertical extreme points of the free spring legs 206a, 206b to the tank wall 201. The free spring legs 206a, 206b transfer part of the spring forces directly to the tank wall 201, as a result of which the inner floating cover 204 is centered well and at the same time the wear of the sealing apron 217a is kept low. Two to four spring clips 206 are connected to a receiving profile piece 211.

10 is a simplified construction for a common primary-secondary seal of a floating roof tank. U-shaped spring clips 106, which open upwards and are arranged in the annular gap 103 between the floating roof 104 and the tank wall 101, are attached to a vertical flange edge of the side wall 104a of the floating roof while simultaneously clamping the edges of a secondary sealing skirt 117 and a primary sealing skirt 122 by means of screws 107 are attached. The upper end of the free leg 106a of each spring clip 106 is fixedly connected by means of a screw 109 to a downward flange of a C-shaped receiving profile piece 111 which is open to the tank wall 101, while simultaneously clamping the outer edge of the secondary sealing apron 117. The receiving profile pieces 111, which are arranged in a ring around the entire tank circumference with small gaps, press a water-stripping secondary sealing element 112 almost completely against the tank wall 101. Here, too, two to four spring clips 06 are connected to a receiving profile piece 111.

On each spring clip 106 is a downward pointing; from the tank wall 101 bent additional spring 40 (by rivets or the like.) Attached. At the free ends of the additional springs 40, a primary sealing element 134 resiliently abutting the tank wall 101 is screwed on while simultaneously tightly clamping the outer edge of the primary sealing apron 122 and an immersion band 131.

The peculiarity of this construction consists in wesentli _- chen that the spring clip 106 in the vicinity of the bent from the tank wall 101 apex regions always have contact with the tank wall with their free legs 106a, whereby the spring clip exert 106 large centering forces on the floating roof 104 without to increase the sealing forces on the sealing elements 112 and 134.

At the contact points between the spring clips 106 and the tank wall 101, slide clips made of preferably non-sparking material can be attached to the spring clips 106, as has already been described with reference to other exemplary embodiments. However, if the strong friction of the spring clips 106 on the tank wall 101 is undesirable, e.g. in the case of coated tank walls, a roller 41 can be attached to each spring clip, as illustrated in FIG. 11. As a result, no sliding friction occurs at the contact points, but only the significantly lower rolling friction, which considerably reduces wear. The rollers 41 are each fastened by means of a bearing block 42 to the free legs 106a of the spring clip by screws 43.

Corresponding roles can also be provided at the tank wall contact points of the exemplary embodiments described above.

Claims (14)

1.Device for sealing the annular gap between the vertical container wall and the floating cover of a large-capacity container, in particular a floating roof tank or a fixed roof tank with an internal floating cover, consisting of a plurality of spring elements fastened at equal intervals next to one another on the circumference of the floating cover, which bridge the annular gap under spring tension and with them free ends press an annularly closed, outer sealing element against the container wall, the annular gap being closed by a sealing apron which runs around the entire annular gap between the outer sealing element and the floating cover, characterized in that U-shaped parts made from narrow strips in a manner known per se Shaped spring clips (6) with one leg end attached to the outer edge of the floating cover (4), that the free spring leg (6a), with the end of which the outer sealing element (12) is rigidly connected, with the sealing element nt and one of them far away in the vertical direction supports the second contact point on the tank wall (1) so that with all movements of the floating cover (4) the reaction forces of the tank wall (1) acting on the contact points of the free spring leg (6a) always keep the free spring leg (6a) in a constantly upright position hold. 2. Device according to claim 1, characterized in that in the case of insufficient length of the free spring legs (6a) skid-like extension arms (6b) are provided in connection to the sealing element (12). 3. Device according to claims 1 or 2, characterized in that when used (the annular gap seal) as a secondary seal (a floating roof tank) the free FedeTschenkel (6a) are so far down that the height difference between the sealing element (12) and floating roof ( 4) is just sufficient to drain the water stripped from the tank wall (1) to the floating roof (4). 4. Device according to one of claims 1 to 3, characterized in that V-shaped extension arms (6b) of the free spring legs (6a) are provided, the legs (6c) returned obliquely upwards, the sealing apron (17) with a narrow annular gap ( 3) support. 5. Device according to one of claims 1 to 4, characterized in that when used as a primary seal (19) and as a secondary seal (2), the U-shaped spring clip (22) of the primary seal and the U-shaped spring clip (6) of the secondary seal their open sides are aligned with each other. 6. Device according to one of claims 1 to 5, characterized in that when used as a primary seal (19) and as a secondary seal (2) between the sealing elements of the primary seal (34) and the secondary seal (12), a connecting apron (33) is used. 7. Device according to one of claims 1 to 5, characterized in that when used as a primary seal (19) and as a secondary seal (2) instead of a connecting apron individual pull straps are used. 8. Device according to one of claims 1 to 3 and 6, characterized in that common U-shaped spring clips (106) are used for primary seal and for secondary seal, which are open at the top, with their free spring legs (106a) over the floating roof ( 104) protrude and reach with their apices deep into the annular gap (103) and the primary and secondary sealing elements (134, 112) are fastened to the ends of the free spring legs (106a) which are far apart in the vertical direction. 9. The device according to claim 8, characterized in that the primary sealing element (134) is pressed by means of separate additional springs (40) on the tank wall (101) which are fastened in the lower region of the spring clip (106) and are dimensioned such that the spring clip (106) always maintains contact with the tank wall (101). 10. Device according to one of claims 1 to 9, characterized in @ that the spring clips (6, 22, 106) at their contact points with the tank wall wear skids (18, 37) or rollers (41). 11. Device according to one of claims 1 to 10, characterized in that the outer sealing element (12, 34, 112) is held in short mutually independent receiving profile pieces, two to four spring clips (6, 22, 106) each with a receiving profile piece (11, 28, 111) are connected. 12. Device according to one of claims 1 to 11, characterized in that the receiving profile pieces (11, 28) with at least one vertically directed flange (10, 13, 27, 29) for attachment to the free spring legs (6a, 22a) and their Extension arms (6b, 22b) are provided. 13. Device according to one of claims 1 to 12, characterized in that the spring clips (6, 22, 106) are made of stainless spring steel. 14. Device according to one of claims 1 to 13, characterized in that the parts sliding against the tank wall (1, 101) are made of spark-free metal.

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