Cleanroom filter unit

Details Cleanroom filter unit Cleanroom filter unit

2000-01-10

2001-08-14

Simmons, David A. (Department: 1724)

Gas separation

Combined or convertible

In environmental air enclosure

C055S355000, C055S483000, C055S497000, C055S502000, C055S511000, C055SDIG003

Reexamination Certificate

active

06273926

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a cleanroom filter unit for airtight attachment to a framework of a cleanroom ceiling, comprising a filter, a vertical circumferential wall surrounding the filter and having a lower edge, and a sealing knife projecting downwardly from the lower edge of the circumferential wall to be received in a sealant containing groove formed in the framework of the cleanroom ceiling.
DESCRIPTION OF THE RELATED ART
In prior cleanroom applications air is generally supplied through so called HEPA-filters arranged in the framework of the cleanroom ceiling. In this connection it is essential that no leakage occurs between the filter and the framework.
Traditional filter units are fabricated by gluing together separate straight wall portions to form the circumferential wall surrounding the filter so that the final filter unit takes the shape of a rectangular box with glued corner joints. The sealing knife comprises vertical extensions of said straight wall portions. Due to the fact that the sealant knife extends downwards into the sealant, i.e. vaseline, in the groove formed in the framework of the cleanroom ceiling a reliable sealing between the filter unit and said framework is achieved in a simple and very efficient manner.
A problem of this known design, however, is that the glued corner joints are not reliable. The fact is that at a rough estimate up to 25% of all corners joints of filter units in use are not completely airtight. Since the gluing surface is so small, normally the thickness of the wall elements of the circumferential wall is about 1.5 mm, very strong demands on the gluing accuracy have to be made. Furthermore, the above described assemblage of a filter unit demands a great deal of work to carry out. To weld the separate wall elements together in order to provide leakproof corner joints is not a good solution to the problem described above, because the heat generated during the welding operation would damage the heat sensitive filter, which is composed of glued fibreglass paper.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a filter unit for cleanroom ceilings, which is reliably tight and has a simple design that enables an inexpensive production of the filter unit.
This object is achieved by the kind of filter unit initially defined, which is characterized in that the sealing knife includes vertical weldable wall elements interconnected by welding and mounted on the circumferential wall by airtight mounting means. As a result the sealing knife of the filter unit has reliable airtight corner joints.
According to a preferred embodiment of the invention the airtight mounting means comprises a profiled frame connected to the lower edge of the circumferential wall and forming a downwards open U-shaped channel into which the vertical wall elements of the sealing knife extend, and moulding mass moulded in said U-shaped channel to secure the sealing knife to said profiled frame.
According to an alternative embodiment of the invention the airtight mounting means comprises a flange connected to the lower edge of the circumferential wall and extending downwards therefrom. The wall elements of the sealing knife vertically overlap said flange and is bonded thereto by gluing.


REFERENCES:
patent: 3870490 (1975-03-01), Landy
patent: 4555255 (1985-11-01), Kissel
patent: 4724749 (1988-02-01), Hedrick
patent: 4819549 (1989-04-01), Gillingham et al.
patent: 4883513 (1989-11-01), Monson et al.
patent: 4986050 (1991-01-01), Brunetti et al.
patent: 5540028 (1996-07-01), Scott et al.
patent: 5620369 (1997-04-01), Sparnsy et al.
patent: 5961702 (1999-10-01), Doneit
patent: 5993311 (1999-11-01), Feller et al.
patent: 6117202 (2000-09-01), Wetzel
patent: 0 190 109 (1986-08-01), None
patent: 0 783 092 (1997-07-01), None
patent: 0 798 027 (1997-10-01), None

Affiliated with

Also associated with

Rating

Cleanroom filter unit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Cleanroom filter unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cleanroom filter unit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2465620