GB2264312A

GB2264312A - Frame member,e.g. for isolator

Info

Publication number: GB2264312A
Application number: GB9203848A
Authority: GB
Inventors: Austin Patrick Mcdonald
Original assignee: Process Containment Tech; STEVTON; Total Process Containment Ltd
Current assignee: Process Containment Tech; STEVTON; Total Process Containment Ltd
Priority date: 1992-02-22
Filing date: 1992-02-22
Publication date: 1993-08-25
Also published as: GB9203848D0

Abstract

A frame for defining the external dimensions of a structure and in particular an isolator structure for use in the pharmaceutical industry which minimises surface irregularities, increases the imperviousness of the chamber and enhances the strength of the frame, is formed of a section member 21 shaped to have a predetermined profile and comprising a marginal flange therealong and a sheet member 22 having a marginal flange and being shaped and in a spatial relationship to the second member 21 such that it fits the profile thereof and is secured thereto by fixing at the flanges e.g. by spot welding, with the flanges in face to face abutment. <IMAGE>

Description

FRAME This invention relates to a frame for providing shape and strength to a structure, and particularly but not exclusively to a frame for forming an isolator or containment device for use in the pharmaceutical industry.

When constructing a structure of any type, it is often required to incorporate one or more panels of glass into a structure, to form, for example, windows. When incorporating a panel of glass into a structure, a join is formed between the panel of glass and the frame of the structure.

In the pharmaceutical industry chambers such as isolators or containment devices are required for the handling of toxic substances, or the handling of sterilised products in a sterile environment.

Isolators comprise a frame made from, for example, stainless steel, and one or more transparent or translucent panels held in position by the frame and serving as windows.

Chambers used in the pharmaceutical industry must be impervious. In other words they must prevent transfer of matter, whether in the form of gas, liquid or solids from the atmosphere into the chamber and vice versa.

If the chamber is to be used for handling toxic substances, it is vital that the toxic substances do not escape from the chamber into the surrounding atmosphere. On the other hand, if the chamber is used as a sterile environment for handling sterile products, it is vital that particles carried in the atmosphere surrounding the chamber do not enter the chamber, thereby rendering the environment in the chamber unsterile.

In addition, it is vital that such chambers are very easy to clean to a high standard. For example, if a chamber has been used to handle toxic substances, it is essential to clean down the internal surfaces of the chamber at the end of its use. In this respect, the surfaces of the chamber, and particularly the internal surface should be as smooth as possible. The presence of bumps and other irregularities on the surface make it difficult to completely clean a chamber.

In the pharmaceutical industry there is a standard set of guidelines governing the manufacture of chambers and other products, known as GMP (good manufacturing practice).

Chambers for use in the pharmaceutical industry must meet the CMP guidelines.

During use of a chamber, there is likely to be a pressure differential between the atmosphere surrounding the chamber, and the internal atmosphere of the chamber. For example, when the chamber is used to handle toxic materials, the pressure within the chamber will be lower than atmospheric.

In order that the transparent or translucent panels are securely fitted into the frame of the chamber, the frame is profiled, and the transparent or translucent panels are profiled in a complementary manner.

Our co-pending patent application of even date and entitled Glass Laminate" refers to a glass panel of such a chamber, and reference is herein directed to the contents of that application.

It is known to form a frame having a desired profile from a steel section having a substantially rectangular cross sectional shape. The desired profile is then formed by welding one or more strips of metal of appropriate dimensions to the steel section, to form one or more lips of appropriate size and shape.

A disadvantage of this known profiled frame is that the welding is time consuming and therefore expensive.

A second disadvantage is that tiny holes may be present in the welding, which holes allow particles to escape andlor enter the chamber, causing contamination of either the contents of the chamber or the surrounding atmosphere.

A further disadvantage is that the welds produce a bumpy surface on the internal surface of the chamber, which means that it is difficult to clean the chamber to the high standards required in the pharmaceutical industry.

According to the invention there is provided a frame for defining the external dimensions of a structure comprising: a section shaped to have a predetermined profile; and a sheet fixedly attached to the profiled section and shaped to fit the profile of the frame, to provide an internal surface to the structure.

The sheet effectively forms an inner skin which extends the between the frame of the structure and thus forms an internal surface of the structure. In other words, by means of the present invention, continuous profiling of the surface of a structure is achieved.

It had previously been thought necessary that in order to provide appropriate strength to a structure such as an isolator, it was necessary to use a steel section having a substantially rectangular crosssection to form the frame.

However, the inventors of the present invention have realised that, the section may be profiled to have any desired shape.

A sheet is then fixedly attached to the frame work to provide, for example, the base or top surfaces of the structure.

The sheet may be fixed to the frame by means of spot welding to the external surface of the frame. By means of the invention therefore, the amount of welding is significantly reduced, and in addition, the presence of welding on the internal surface of the is significantly reduced. This is particularly desirable when the structure comprises a chamber for use in the pharmaceutical industry, where the presence of welding on the interior of the chamber can reduce the imperviousness of the chamber, and also render the chamber difficult to clean and sterilise.

The invention will now be further described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic diagram of a known profiled frame; Figure 2 is a schematic diagram of a section of a frame according to the present invention; Figures 3 and 4 are more detailed drawings of the frame of Figure 2.

Referring to Figure 1, a known sectioned profile is designated generally by the reference numeral 10. The known profile is made up of a steel section 11 having substantially rectangular cross section. The desired profile is then created by welding a strip 12 onto the section 11, by means of welds 13. This known profile thus includes numerous welds 13 on the internal surface of the chamber being formed by the frame work 11.

Referring to Figure 2 a profiled frame according to the present invention is designated generally by reference numeral 20. The frame comprise a profiled section 21. The section 21 has been shaped to have a predetermined profile, and does not have a substantially rectangular or square crosssection. Instead, the section 21 is shaped to form lips 22 as appropriate for the design of the structure being formed. A sheet 23 is then fixedly attached to the frame 21 and shaped to have a complementary profile to that of the frame 21. The sheet 23 may be attached to the frame 21 by means of spot welding (see Figure 3). The spot welding takes place on the external surface of the frame, rather than on an internal surface of the structure.This reduces the number of welds on the internal surface of the structure, which thus reduces the irregularities in the level of the internal surface of the structure. In addition, the sheet 23 provides continuous profiling of the structure.

A frame according to the present invention is particularly appropriate for use in forming an isolator or containment device, for use in the pharmaceutical industry. In such chambers, the presence of welding on the internal surface of the isolator or containment device potentially reduces the imperviousness of the chamber. This is due to the fact that tiny holes may exist in the welding, which allow particles to either enter or exit from the chamber, thus causing contamination of the internal atmosphere of the chamber, and/or the external atmosphere.

In addition, the presence of welding on the internal surface of such a chamber results in irregularaties in the height of the internal surface of the chamber. In other words, the welding protrudes above the general level of the internal surface thus causing bumps. The presence of the bumps makes it more difficult to sterilise and clean the chamber after use to the required high standard necessary in the pharmaceutical industry.

Claims

CLAIMS:

1. A frame for defining the external dimensions of a structure and comprising at least part of the periphery thereof: a section member shaped to have a predetermined profile and comprising a marginal flange therealong; and a sheet member having a marginal flange and shaped and in a spatial relationship to said section such that it fits the profile of the frame, is secured thereto by fixing at said flanges, with said flanges in face-toface abutment and extends from said flange thereof to provide an internal surface to the structure.

2. A frame according to Claim 1, wherein the section member is of non-rectilinear section.

3. A frame according to Claim 1 or 2, wherein the sheet forms the base or top surface of an isolator structure.

4. A frame according to any preceding claim, wherein said fixing has taken place by spot welding.

5. A frame for defining the external dimensions of a structure, substantially as hereinbefore described with reference to and as shown in Figures 2 to 4 of the accompanying drawings.