WO2012074348A1

WO2012074348A1 - Air-tight connection mechanism for the frames of a non-perforated honeycomb-type floating internal membrane panel

Info

Publication number: WO2012074348A1
Application number: PCT/MX2010/000141
Authority: WO
Inventors: Enrique Sergio Borjes Velazquez
Original assignee: Enrique Sergio Borjes Velazquez
Priority date: 2010-11-30
Filing date: 2010-11-30
Publication date: 2012-06-07

Abstract

The invention relates to a mechanical lock-type air-tight connection mechanism for connecting a panel assembly that comprises a non-perforated honeycomb-type floating internal membrane, achieving a very strong, durable and leak-free connection between the perimeter frames of each panel, and one that is completely air-tight and does not allow vapors or liquid product to penetrate the upper part of the membrane owing to the intermediate seal, thereby preventing the panels from possibly separating during turbulence or an earthquake, thus resulting in a very strong structural assembly. The invention is intended to provide a connection between the panels that comprise the non-perforated honeycomb-type floating internal membrane in a highly effective manner that, although similar, is yet completely different from designs already on the market, owing to a novel design and construction, the principal characteristic of which is to combine similar characteristics of other designs, but more effectively, safely and durably.

Description

HERMETIC UNION MECHANISM BETWEEN FRAMEWORK PANELS OF THE FLOATING INTERNAL MEMBRANE TYPE OF NON PERFORATED BEE

FIELD OF THE INVENTION:

The present invention, applied in the field of operation and safety technology of hydrocarbon storage tanks within the facilities of the national oil industry and specifically, refers to the mechanism for joining the profiles that form the perimeter frame of each panel and the entire set of floating internal membrane panels to achieve a safe, efficient and long-lasting operation.

OBJECT OF THE INVENTION:

The aim of the present invention is to achieve a highly hermetic and highly resistant joint between the profiles that form the perimeter frame of the panel, in order to eliminate evaporation of the product stored in all joints of the assembly.

It is another objective to increase the safety in the operation of filling and emptying the tank due to the structural strength of this new design to perfectly withstand any load.

It is worth mentioning that with this objective and its development, it is intended to comply with the requirements and specifications indicated in the national and international standards and / or standards both the Pemex NRF-207-pemex-2007 standards and those indicated by the API-650 appendix bulletin Ή "

BACKGROUND:

Since the first time that liquid fuels were stored in vertical cylindrical tanks with fixed roof, product losses due to evaporation, fire risks and environmental pollution, were considered the areas of greatest concern. Evaporation occurs on the surface of the stored liquid, and can be minimized or eliminated, reducing the amount of surface exposed to the atmosphere, eliminating this evaporation, also reducing the amount of vapors that are removed from the inside of the tank to the outside , and that are another form of environmental pollution.

These areas of concern were the starting point for the design of a device that would eliminate evaporation of the stored product to the maximum, by contact with the surface of said product, that would be durable, efficient and that would provide safety in its operation.

The American Petroleum Institute (API) in its standard 650 appendix "H", defines and recommends the minimum quality with which the user can select the most economical alternative when safety and cost are the most important, however a Improved design which can have an initial high cost, in the long run it may be the best option since the expected life, its operation and efficiency, can be longer and the maintenance or replacement of worn or damaged parts, can be the minimum.

INTERNAL FLOATING MEMBRANE STD DESIGN:

In general terms, the M.I.F. of std design. It is made up of an aluminum cover, which is supported by a grid of profiles of the same material, and in turn this set is supported by pontoons or floats, which can also function as beams. This cover is surrounded by a perimeter seal, which must be resistant to the stored product, and resistant to - 2 - ruptures and abrasion against the tank wall, for many cycles of emptying the tank.

MIF is a device that is installed inside a vertical type storage tank, with fixed steel roof or with aluminum geodesic dome, at atmospheric pressure and at ground level, being its main purpose to eliminate evaporation losses to the maximum of the stored product, such as crude oil, gasoline, solvents, etc. The design of the membrane must meet at least the recommendations and / or requirements indicated in API bulletin 650 appendix "H" (latest edition bulletin API-650-2001).

Although in its design most of the M.I.F. they meet the minimum of the requirements indicated by API 650 appendix "H" (last edition bulletin API-650-2001), many of these designs have developed very poorly, and sometimes with a lot of publicity, the problems that have been found have been result of the low resistance to turbulence (low mass, and low weight depending on the specific gravity of the product and its viscosity), design deficiencies (joints and profiles or thin frames) (must be at least 0.125 ") , and on the other hand the flotation factor, which is of the utmost importance since some manufacturers, do not respect the specified flotation factor, or cannot give it, due to their own design, and due to the geometry of this design, the flotation elements are not the required ones, and in the case of contact or honeycomb membranes, the dimensions of the panels they handle as standard, the flotation is poor resulting in a minimum of flotation and therefore Both the product can sprout towards the top cover.

On the other hand, the poor design criteria result in structural details of very low resistance, in addition to the low corrosion resistance due to the poor selection of suitable aluminum.

-5 -

An M.I.F. Well designed, it results in a structurally resistant, durable device with the required flotation (without adding extra flotation devices), corrosion resistant, and resistant to turbulence or earthquake. An aluminum membrane is very low cost, if we compare it with the cost of the steel roof, especially if the selection is based strictly on a cost that exceeds the minimum of the specified requirements.

On the other hand, when there is presence of liquid on the membrane cover, it can be the result of design deficiencies such as the use of false or inadequate joints between cover overlaps or between panels, and / or specific gravity factors above 0.7. Although API 650 suggests specific gravity factors for proper operation and for a wide range of hydrocarbons, which allows the use of high specific gravity factors, the expected life along with the flotation and flexibility of the service could reduce et cost.

INTERNAL FLOATING MEMBRANE TYPE PONTONES AND COVER M ALUMINUM:

In the design of this type of membrane, the aluminum cover is, above the surface of the stored product, resulting in saturated steam spaces, below the cover which can be of serious consequences in case of fire, if it has not been installed with the highest quality, since any bad tightening, bad union, or bad overlapping, could cause at least a constant atmosphere of stored fuel vapors or a possible fuel. This type of membrane was developed in the 1970s, using pontoons as floats and as a support beam, as well as a grid of aluminum profiles as a cover support. At present, there are many membranes of this type, designed and manufactured with very poor quality, and with many problems

-4 - maintenance and / or operational efficiency, however its existence is due, ¾ which is a low cost alternative, and most of these only meet the minimum of the specified requirements, or less if the specific gravity factor , was identified at the time of purchase or to be agreed upon by the manufacturer.

INTERNAL FLOATING MEMBRANE TYPE OF BEE PANEL NOT PERFORAD ©:

The design of this type of membrane, is of total contact with the surface of the product and was preceded by another design dating from the 1950s which -s- used rigid closed-cell urethane foam panels, joined by an aluminum tape and with thin aluminum covers.

5 The original design was developed in two variations:

A) Panels 3 -0 "wide, by 6 -0" long, with perimeter frame joined by adhesive (developed in the 1970s), resulting in detachment between panels due to a false joint (see Fig. 1 ). id

B) Panels of 3'-0 "wide, by 6'-0" in length with perimeter frame joined by welding (developed in the 1990s) in this design, the overall weight m is greater due to the perimeter welding of the panel frame against lower-upper covers resulting in greater thickness or peraH®

15 faithful panel, in order to compensate for the overweight of the welding bead, and thus be able to provide the required flotation, but the risks of sinking due to perforations in the roofs, may be greater (see Fig. 2).

In both designs, the core of the panels is laminated aluminum in the form of honeycomb and the roofs are normally made of thin aluminum; These panels are joined together by means of tornittSL

VARIATION A):

25

FIG. 1 Panels 3 -0 "wide by 6'-0" in length, attached with adhesive to the profiles that form the frame throughout its perimeter, joining the panels, by means of "Rails", which function as staples of clamp (3) and (4), against small bumps 1/16 "high in each frame, one upper and the other

30 bottom, crossing the entire cantilever of the panel clamping molding by means of aluminum screws (5) of ¼ "by 3" or 4 "in length @ 6" leaving a gap between the panels of approx. 3/8 "without any intermediate packing, resulting in this design, a large number of joints between panels, and a non-hermetic joint without mechanical lock, which, when having load on the panel, or by

35 turbulence, these can be released (7) and the stored liquid leaks easily (6) through this "joint" towards the top of the membrane, being sealed above these rails with a sealant-adhesive in all joints. There are four documented cases, which means rework to a team that to date has been marketed at a high price, but with very low quality in every way. Figure 1 (honeycomb not perforated and frames glued with adhesive), shows a sectional view of the joint between panels, where it can be seen that this type of joint allows a space of approximately 3/8 ", likewise It can be seen that the connecting screw (5) passes from side to side by tightening the upper (3) and lower (4) clips without seal, allowing this space to be filled with the product (liquid) which in turn evaporates escaping from the top, and to avoid this, it has to be resealed, from the top, it can also be seen that this joint is not rigid but flexible, and the panels can be detached.

VARIATION B):

Fig. 2 Panels 3'-0 "wide by 6'-0" in length, welded to the profiles that form the perimeter frame, butt joined between their faces against the other panels, with lower fixing system insertion (14) and with screws laterally at the top (15), but because the panel is thicker (3 "to give the required flotation due to the weight of the weld), and of greater weight (more material) therefore, a non-hermetic union without mechanical lock is achieved with which with load on the panel, or by turbulence, these can be detached from its bottom (7), and the easily stored liquid passes through this "union" to the upper part of the membrane (6), which is contained, because the upper fixing part protrudes 1 "from the upper cover of the panel, becoming liquid containers, and overweight throughout the set, you can collapse it. This is a team that to date has been commercialized at a high price, and if we think about the initial investment, this type of membrane is possibly the one with the highest economic outlay. Figure 2 (perforated honeycomb and welded frames), shows a sectional view of the joint between the panels (1) and (2) butt between their outer faces, it can be seen that the joint at the bottom , it is of the insert type (14), and on the top it is of the type screwed on the side (15), it does not use any type of seal, the The cantilever of the panel is 3 ", it weighs twice the previous one, the part of the upper fixing allows product or water stagnation, the panels can be detached from their lower union.

VARIATION "C"

Derived from the design of the variable "A", this design that exists in the state of the art, consists of panels 4'-0 "wide by 10'-0" in length, with fewer joints and less screws, against the 3 -0 "by 6'-0" design which due to its dimensions, has a large number of joints and excess hardware, which is an extra weight and also very flexible, and therefore easy to damage by detachment of the panels. BRIEF DESCRIPTION OF THE INVENTION:

The design presented, of panels of larger dimensions (4'-0 "wide by 10'-0" in length) and fewer joints in the assembly, and as a consequence less screws, gives us a more stable and resistant membrane turbulence or earthquake, and is based on non-perforated panels (1) and (2) that are bonded with adhesive to the profile of the newly designed perimeter frame (3) and (4) above and below, joining the panels to topé between its external faces, by means of section profiles of very low profile, one upper (5) and one lower (6), which function as a top and a lower clamp, fixing them against the profile of the frames of the panels, by means of self-drilling pins (7) and (8) stainless steel ¼ "by 5/8" in length to 6 ", a cross-section polyethylene packing section is also placed between the panels ( 9), 100% aromatic resistant, thus achieving a completely hermetic union, with mec lock Unique and structurally resistant, which means that with a load on the panel, or due to turbulence, these cannot be detached and the stored liquid does not pass through this "junction" to the upper part of the membrane eliminating any product pooling, complying with or exceeding the requirements indicated by both API-650 appendix Ή "(last edition API-650-2001), as well as those indicated by Petróleos Mexicanos, it should also be mentioned that due to the intermediate packing, the stored liquid or its vapors, no pass through this union, to the upper part of the membrane, eliminating any waterlogging or gasification of the product. This is a team that has been marketed at a price, highly competitive, and with high quality in every way.

DETAILED DESCRIPTION OF THE INVENTION:

In accordance with the above, and due mainly to the failures that have been presented in the previous designs, it was thought of a design that would provide greater stability as a whole, less amount of joints and screws, and greater resistance in the joint between panels , which will prevent the detachment between panels, that would be totally hermetic and highly safe in the structural aspect, since these have been the points where more failures have occurred in this type of membrane.

In this invention (Fig. 3 isometric projection and Fig. 4 side view), in order to make the joint work as a padlock and be completely hermetic, a new profile of the perimeter frame was designed, where when placing the self-drilling pins (? ) and (8), which, due to their conical section characteristics, tend to separate the two sections of the frames (3) and (4) that join the panels (1) and (2), the aluminum ca * section of Low profile (5) and (6) that is placed along the frame at the end where the edges or tabs (10) and (11) of the perimeter frame were designed, functioning as a clamp and padlock, preventing the frames perimetral (3) and (4) separate or open beyond what its section allows, and therefore it is practically impossible for this union to separate and could allow vapors or product leakage, in addition the panel assembly maintains tight and in place to the gasket or intermediate seal (9), which is housed in the longitudinal channel medium (2) of the perimeter frame, which being cross-chain polyethylene, is totally resistant to aromatics and solvents, as well as high and low temperatures

GENERIC DESCRIPTION OF THE COMPONENTS: Panels, parts (1) and (2) of 1.5 "of cant by 4'-0" in width by 10'-0 "in length constructed with: a) Honeycomb configuration core (hexagonal cells) in sheet of 3003-H14 aluminum 0.003 "thick.

b) 3003-H14 aluminum foil covers 0.025 "thick (API-650-H in tíca 0.016" being the standard for others)

c) Extrusion of the new design perimeter frame, aluminum 6062-T6 1.5 "internal cant by 2.0" of skate by 0.125 thickness, parts (3) and (4).

d) Extrusion of the 6062-T6 aluminum fixing clamp, low profile channel section, 1 "wide by 0.5" cant, 10'-0 "in length, parts (5) and (i)

&) ¼ "0 by 5/8" length 304 stainless steel self-drilling plunger, parts (7) and (i)

f) 3/8 "cross chain polyethylene intermediate seal of square section by required length, part (9)

PREFERRED MODE OF THE INVENTION: As can be seen in Figures 3 and 4, where the components that form the present invention are indicated, the preferred embodiment is formed by:

1. panels (1) and (2), to be joined by means

2. Newly designed perimeter frames (3) and (4), with longitudinal, upper and lower edges or tabs (10) and (11), with their middle longitudinal channel (12) where it is housed:

3. The polyethylene material for intermediate seal (9),

4. the fixing clips (5) and (6), and

5. the fixing pins (7) and (8).

Claims

REINVINDICATIONS

Having described my invention as above, I consider a novelty and claim of my property, what is contained in the following clause:

1- Improvements in the mechanism of hermetic union type mechanical lock, to join the set of panels that make up a floating internal membrane, honeycomb type not perforated, through the perimeter frames (3) and (4) of each panel, characterized by a clamping means comprising an upper self-drilling pin (7), a lower self-drilling pipe (8) which join the perimeter frames by means of an upper aluminum clip (5) and a lower aluminum clip (6) and a cross-chain polyethylene gasket (9) between the perimeter frames of each panel).

2.- Improvements in the mechanism of hermetic union type mechanical lock, to join the set of panels that make up a floating internal membrane, honeycomb type not perforated, through the perimeter frames of each panel, further characterized by said perimeter frame It has a lateral longitudinal channel to accommodate the panels (1) and (2), two protruding longitudinal edges or flanges, an upper one (10) and a lower one (11), and a central lateral longitudinal channel (12) where houses the polyethylene material (§).