Tank Liner

Abstract

A corrosion-resistant and leakproof liner for tanks formed of flexible material and suitable for use on a variety of tanks having different sized cleanout openings. The liner has a transversely extending tubular neck portion having transverse dimensions corresponding to the transverse dimensions of the smallest standard cleanout opening of a tank of a particular size. The tubular neck portion of the liner is extended through the cleanout opening and then overlaps the flange provided on the outer end of the cleanout opening neck. When the transverse dimensions of the cleanout opening are larger than the transverse dimensions of the tubular neck portion of the liner, a lightweight support is positioned in the cleanout opening and supports the tubular neck portion of the liner to prevent collapse of the tubular neck portion of the liner and maintain a cleanout opening for the tank.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to improvements in tanks, and more particularly to an improved liner construction and method of lining an existing tank.

2. Description of the Prior Art

As it is well known in the art, tanks are utilized for storing a great variety of fluids, some of which are highly corrosive. The service life of a tank will, of course, vary with the environmental conditions. In any event, a tank will at sometime become corroded and develop leaks. Most tanks, particularly in the oil industry, are relatively expensive and it has been found economical to line a corroded tank rather than to replace the tank.

A popular method of lining a tank is to apply a coating of a corrosion-resistant, plasticlike material on the internal surfaces of the tank. However, this method of lining requires an extensive amount of preparation of the tank, particularly in cleaning and treating the internal surfaces of the tank, and results in a relatively expensive installation.

It has also been known to support a flexible liner in an existing tank. However, the cleanout openings in existing tanks of the same capacity vary over a wide range, and prior to the present invention it has been found necessary to provide a special liner for each design of tank, making the inventory requirements for the liners prohibitive and preventing the standardization of liner configurations with the attendant economies in manufacture of the liners.

SUMMARY OF THE INVENTION

The present invention contemplates a flexible liner for a tank of a particular rated capacity, irrespective of the size of the cleanout opening in the tank. The flexible liner has a tubular neck portion extending from one side thereof having transverse dimensions corresponding to the smallest standard cleanout opening of tanks having a rated capacity for which the liner is designed. The tubular neck portion of the liner is extended through the cleanout opening of the tank, and in the event the transverse dimensions of the tubular neck portion of the liner are less than the transverse dimensions of the cleanout opening, a lightweight support is fitted in the cleanout opening around the neck portion of the tubular liner to support the intermediate portion of the tubular neck portion of the liner and retain a cleanout opening for the tank of the minimum standard size. The neck portion of the tubular liner overlaps the flange provided around the outer end of the cleanout opening, and the excess material in the tubular neck portion of the liner is cut off in such a manner that the transverse dimensions of the free end of the tubular neck portion of the liner correspond with the transverse dimensions of the cleanout opening flange. A sheet of material corresponding to the liner is also preferably placed over the face of the cleanout opening cover plate facing the interior of the tank to completely shield the internal surfaces of the tank from the fluid being stored in the tank.

The present invention also contemplates a method of lining an existing tank which results in the liner construction defined in the preceding paragraph.

An object of the invention is to extend the service life of existing tanks.

Another object of the invention is to provide a corrosion resistant and leakproof liner for existing tanks, irrespective of the sizes of the cleanout openings in the tanks.

Another object of this invention is to provide a liner which may be utilized in a variety of designs of tanks of a given rated capacity.

A further object of this invention is to provide a versatile tank liner which may be economically manufactured, easily installed, and which will have a long service life.

Other objects and advantages of the invention will be evident from the following detailed description when read in conjunction with the accompanying drawing illustrating the invention.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a typical storage tank having the present liner installed therein.

FIG. 2 is a perspective view of the liner of this invention.

FIG. 3 is a partial sectional view through an upper corner of a tank having the present liner installed therein as taken along lines 3--3 of FIG. 1.

FIG. 4 is a sectional view as taken along lines 4--4 of FIG. 3.

FIG. 5 is a sectional view through the cleanout opening of a tank having the present liner installed therein, as taken along lines 5--5 of FIG. 1.

FIG. 6 is an elevational view of a typical support to be employed in the cleanout opening of a tank when installing the present liner therein.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present liner construction will be described as being used with storage tanks employed in the oil industry, although it will be understood that the liner may be employed in virtually any type of storage tank with beneficial results.

Referring to the drawings in detail, and particularly FIG. 1, reference character 10 designates a typical oilfield storage tank having the present liner installed therein. The tank 10 is typically a cylindrical tank, having a top 12 and bottom 14, and is normally a steel tank, either welded or bolted, but may also be wooden. A cleanout opening 16 is provided in one side of the tank 10 in a position to extend through the wall of the tank from the bottom 14. API (American Petroleum Institute) specifications require that the cleanout opening be of a rectangular configuration, but may be of various dimensions. For example, in a 200 barrel capacity tank, the minimum dimensions of the cleanout opening 16 are 20 inches by 24 inches, but may be larger, such as 24 inches by 36 inches. In any event, a neck 18 normally extends outwardly from the side of the tank 10 around the cleanout opening 16 and terminates in a mounting flange 20 on the outer end thereof. A cover plate 22 is secured to the mounting flange 20 by bolts 24 to close off the cleanout opening 16.

The liner of this invention is illustrated in FIG. 2 in an uninstalled, but expanded disposition and is designated by the general reference character 26. The liner 26 is formed of a flexible material, preferably about 30 mils thick, and is preferably formed of a corrosion-resistant material, such as a synthetic rubber or a thermoplastic vinyl, the formulation of the material depending upon the service conditions being encountered. The thickness of the liner 26 is exaggerated in the drawing for clarity of illustration. The liner 26 comprises a tubular body portion 28 having a diameter and height substantially corresponding to the diameter and height of a tank 10 of a particular capacity. In other words, the diametrical and height dimensions of liners constructed in accordance with this invention will be standardized with respect to the diametrical and height dimensions of the tanks in which the liners are to be employed, there being a particular size of liner for each tank size.

The bottom 30 of the liner 26 is closed to provide a protective covering over the bottom 14 of the tank 10. The top of the body 28 of the liner 26 is open and the upper edge of the body 28 is lapped or turned downwardly and sealed to the body 28 along a line 32 to provide a hem portion 34. A plurality of circumferentially spaced openings 36 are cut in the upper edge of the hem 34 for purposes to be described.

A tubular neck portion 38, preferably of rectangular configuration in cross section, extends radially outward from the side of the liner body 28 adjacent the bottom 30 of the liner. The transverse dimensions of the neck portion 38 correspond to the minimum transverse dimensions of the cleanout opening which may be encountered in a standard tank of the capacity for which the body 28 is sized. For example, for a 200 barrel tank, the transverse dimensions of the neck portion 38 would be 20 inches by 24 inches. The length of the tubular neck portion 38 is substantially equal to the length of the cleanout opening neck 18 of the tank 10 in which the liner is to be utilized. A rectangular flap 39 is formed on the outer end of the neck portion 38 and has transverse dimensions greater than the transverse dimensions of the flange 20 which may be encountered.

Prior to the installation of the liner 26 in the tank 10, the inner surfaces of the walls and the bottom 14 of the tank are preferably cleaned and all sharp edges on such surfaces removed. Also, a series of holes 40 are drilled through the top 12 of the tank corresponding in number and arrangement to the openings 36 in the hem 34 of the liner 26.

The liner 26 is then collapsed and inserted in the tank through the cleanout opening 16. A worker can then enter the tank and thread a tube 42 (FIGS. 3 and 4) through the hem 34 at the upper end of the liner. The tube 42 may be a plastic tube of any particular size or design which can be threaded into the hem 34 and the ends welded together to form a ring. The lower end of a J-bolt 44 is then looped under the tube 42 at each of the liner openings 36 and extended upwardly through one of the holes 40 in the top 12 of the tank. Another worker places a nut 46 on each of the J-bolts 44 from the exterior of the tank. The body 28 of the liner 26 will therefore be suspended in the tank 10.

The tubular neck portion 38 of the liner 26 is then extended through the cleanout opening 16 of the tank. In the event the transverse dimensions of the cleanout opening 16 correspond to the transverse dimensions of the tubular neck portion 38, the flap 39 is simply extended radially outward over the mounting flange 20 and cut off to be flush with the outer periphery of the mounting flange 20. However, as previously noted, the transverse dimensions of the cleanout opening 16 are normally larger than the transverse dimensions of the tubular neck portion 38. In this latter event, a support 48 is placed in the cleanout opening 16 around the tubular neck portion 38 to support the tubular neck portion 38 and still provide a cleanout opening for the tank.

Prior to installation, the support 48 has the configuration illustrated in FIG. 6. A bore or opening 50 is formed through the support 48 having transverse dimensions corresponding to the transverse dimensions of the tubular neck portion 38, and preferably with the corners 52 of the bore 50 rounded. The overall transverse dimension, noted as A and B in FIG. 6, of the support 48 correspond to the transverse dimensions of the largest standard cleanout opening for the tank being lined. In the event the overall transverse dimensions, A and B, of the support 48 are larger than the transverse dimensions of the cleanout opening 16 of the tank being lined, the support 48 is trimmed to the necessary extent to fit within the cleanout opening 16 being encountered. In a preferred form, the support 48 is made of a styrene plastic material and is easily trimmed with a knife to fit tightly in the cleanout opening 16.

Upon installation of the support 48, the tubular neck portion 38 is extended through the opening 50 in the support 48 and then the flap 39 is extended radially outward over the outer face of the support 48 and over the mounting flange 20. Any excess material remaining in the flap 39 can be easily trimmed, such that the outer edge of the flap 39 will conform to the outer periphery of the mounting flange 20.

To complete the lining of the tank 10, a sheet 54 of material corresponding to the material employed in the liner 26 is placed over the face of the cleanout cover 22 facing the interior of the tank 10, and a spacer washer 56 is placed between the sheet 54 and the corresponding portion of the tubular neck portion 38 in line with the mounting flange 20; whereupon the cover plate 22 is secured to the mounting flange 20 by the bolts 24. The tank 10 will then be lined, with all surfaces of the tank in contact with the fluid being stored protected by a corrosion-resistant and leakproof material, and with a cleanout opening still provided in the tank upon removal of the cover plate 22.

From the foregoing it will be apparent that the present invention will increase the service life of existing tanks. The liner of this invention may be used on a variety of tank designs to permit the maximum standardization and minimize inventory requirements. Installation of the lining is accomplished in a minimum of time and with a minimum of effort.

Changes may be made in the combination or arrangement of parts or elements, as well as the arrangement of steps or procedures, as heretofore set forth in the specification and shown in the drawings without departing from the spirit or scope of the invention.

Claims

What is claimed is:

1. In combination with a tank having a top and bottom, a cleanout opening in one sidewall thereof surrounded by a neck, and a mounting flange around the outer end of the neck to mate with a cover plate for the cleanout opening, the improvement comprising:

a liner of flexible material suspended in the tank and covering the sidewalls and bottom of the tank;

said liner having a tubular neck portion extending from a side thereof through the tank cleanout opening, and having a flap on the outer end thereof overlapping the mounting flange;

said tubular neck portion having transverse dimensions less than the transverse dimensions of the cleanout opening neck;

said flap having dimensions such that it is of larger area than said mounting flange and projects beyond said mounting flange in directions away from said neck;

a support positioned in the cleanout opening neck around the tubular neck portion of the liner and supporting that portion of the tubular neck portion of the liner transversing the cleanout opening neck, said support being formed of an easily worked synthetic resin material for fitting in said cleanout opening snugly around said tubular neck portion of said liner; and

a sheet of corrosion-resistant material positioned over the face of the cleanout opening cover plate facing the interior of the tank and extending between the cleanout opening cover plate and the mounting flange.

2. The combination defined in claim 1 wherein a hem is formed around the upper end of the liner and characterized further to include a support tube positioned in the hem, and means suspending the support tube from the top of the tank.

3. The combination defined in claim 1 wherein said support is formed of styrene plastic.

4. In combination with a tank having a top and bottom, a cleanout opening in one sidewall thereof surrounded by a neck, and a mounting flange around the outer end of the neck to mate with a cover plate for the cleanout opening, the improvement comprising:

a liner of flexible material in the tank open at its upper end and covering the sidewalls and bottom of the tank, said liner having a tubular neck portion extending from a side thereof through the tank cleanout opening and having a flap on the outer end thereof overlapping the mounting flange, said tubular neck portion having transverse dimensions less than than the transverse dimensions of the cleanout opening neck, said liner also having a hem formed around the upper end thereof;

a support tube positioned in said hem;

means suspending the support tube from the top of the tank and thereby suspending the liner in the tank; and

a support positioned in the cleanout opening neck around the tubular neck portion of the liner supporting that portion of the tubular neck portion of the liner transversing the cleanout opening neck.

5. In a method of lining a tank having a top and bottom, a cleanout opening in one sidewall thereof surrounded by a neck, and a mounting flange around the outer end of the neck to mate without a cleanout opening cover plate, the steps of:

forming a flexible liner in a shape to cover and contact the sides and cover the bottom of the tank and have a tubular neck portion on one side thereof with a rectangular flap on the outer end thereof and having transverse dimensions less than the transverse dimensions of the cleanout opening and a length substantially equal to the length of the cleanout opening neck;

suspending the liner in the tank with the tubular neck portion of the liner mating with the cleanout opening;

fitting a support in the cleanout opening neck;

forming an opening through the support conforming to the transverse dimensions of the tubular neck portion of the liner;

extending the tubular neck portion of the liner through the support and the flap radially outward over the mounting flange;

cutting off that portion of the flap of the liner extending radially beyond the mounting flange;

securing the cleanout opening cover plate to the mounting flange over that portion of the tubular neck portion of the liner overlapping the mounting flange.

6. The method defined in claim 5 wherein the liner is formed about 30 mils thick.

7. The method defined in claim 5 wherein the support is formed of styrene plastic.