Gas and liquid contact apparatus – Contact devices – Wet baffle
Reexamination Certificate
2000-08-11
2002-10-08
Bushey, C. Scott (Department: 1724)
Gas and liquid contact apparatus
Contact devices
Wet baffle
C261S112200, C261SDIG001
Reexamination Certificate
active
06460832
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to film fill sheets making up fill packs used in liquid cooling apparatus, and especially to film fill sheets each having repeating, successive surface area-increasing patterns. The film fill sheets are each configured to be arranged in a shingled bundle in nested relationship for shipping. The shingled bundle may be mounted as a unit on the support structure for the fill pack in the cooling tower apparatus. Thereafter, the bundle may be expeditiously expanded in place by effecting relative movement between the sheets while supported by the support structure to unshingle the bundle and thereby unnest the surface area-increasing patterns of adjacent sheets. The expanded, unshingled bundle thus forms all or a part of the fill pack in the liquid cooling apparatus.
DESCRIPTION OF THE PRIOR ART
Film type fill media in the form of a fill pack has been used for many years in liquid cooling apparatus such as water cooling towers. Film type media generally takes the form of a large number of individual film fill sheets configured and oriented to present both a liquid path and a fluid cooling medium path therebetween with each sheet of the pack providing a relatively large surface area over which the hot liquid being cooled spreads into a relatively thin film, on opposite faces of each of the sheets. A coolant fluid such as cool ambient air is then drawn over the large surface area of the liquid film causing the liquid to be cooled by direct contact of the coolant fluid with the hot liquid. In the case of hot water, the water is cooled evaporatively. The individual fill sheets are generally fabricated of a flexible material such as a synthetic resin and are therefor not capable of standing by themselves when formed into a pack. Two methods of supporting film fill type media are commonly used to install film fill packs in cooling towers.
One method of providing support is to glue a plurality of film fill sheets into requisite packs and to support the fill packs by stacking them on underlying structural supports. By gluing the film fill sheets together at discrete contact points, a lattice type structure is developed which thereby contributes substantial strength to the overall pack. Gluing of the sheets is especially useful in fabrication of fill packs made up of cross-corrugated film fill media. An exemplary cross-corrugated fill pack is disclosed by Munters in U.S. Pat. No. 3,415,502 (Liquid and Gas Contact Body). A major disadvantage of the gluing method is the fact that cross-corrugated film fill packs inherently are dominated by air voids. Pack gluing usually takes place in a factory. This makes for inefficient shipping as most of the pack is air and the packs must be handled multiple times during shipment and installation.
Mobile pack-making machines have been used at the site of very large towers to overcome the shipping disadvantage. Nested film fill sheets with little or no air voids and glue are shipped to the location of the mobile pack-making machine near the tower under construction where the packs are made. Pack fabricating equipment, however, is very expensive, requires set-up at and then removal from the point of usage, and necessitates the provision of weather protection structure for the equipment.
Mobile pack making is expensive not only because of the capital costs incurred, but also because it is necessary to hire a crew, train that crew, prepare a staging area, and to purchase insurance, obtain permits, etc. which makes it economical for only very large towers and then only for certain favorable ambient conditions. Total handling and installation costs are thus about the same as for factory made packs.
A second common method of installing fill in cooling towers is to hang a plurality of film fill sheets making up a pack from support tubes carried by frame work of the tower. Support tube openings are provided near the top of each of the fill pack film sheets. The sheets are then suspended one at a time from the support tubes placing the sheets in tension except for the very top portion of each sheet. Exemplary film fill sheets used to fabricate fill packs hung from support tubes in water cooling towers are disclosed by Kinney, Jr. et al. in U.S. Pat. Nos. 4,548,766 (Vacuum Formable Water Cooling Tower Film Fill Sheet with Integral Spacers), 4,826,636 (Multi-Level Film Fill Industrial Cross Flow Cooling Tower), and 4,801,410 (Plastic Fill Sheet for Water Cooling Tower with Air Guiding Spacers) and by Bugler et al. in U.S. Pat. No. 5,147,583 (Non-Clogging Film Fill Assembly for Counterflow Water Cooling Tower).
Adjacent film fill sheets must contact one another to keep the sheets properly spaced and to minimize aerodynamically excited vibrations. In cross-corrugated fills as illustrated and described in the '502 patent, and non-clogging film fill as shown and described in the '583 patent, sheet contact is necessary to force the air to repetitively split and regroup, thus mixing the air as it traverses through the fill pack. Additionally, the integral louvers, integral eliminators, and air guiding spacers such as shown and described in the '410 patent form cellular or honeycomb structures, which necessarily require contact by adjacent sheets.
Two film fill surface configurations are generally employed to obtain requisite contact between the cooling fluid medium and the hot liquid within the fill pack. One surface configuration is such that sheets which are nested for shipment may be alternately rotated or flipped over when forming the pack therefrom. Exemplary fill sheets in this respect are found in the '502 and '583 patents. This surface area-increasing geometry has the advantage that all of the sheets are the same.
Another method is to simply make two different complemental sets of film fill sheets which are alternated in the installation, i.e., A, B, A, B, etc. An exemplary fill using film fill sheets of this technique is discussed and illustrated in U.S. Pat. No.9,320,073.
Both of these methods require extensive handling of the individual film fill sheets to orient the sheets properly to form the desired pack. For shipping purposes, in order to avoid the problem of shipping film fill packs in assembled condition, which is largely air, the fill pack is assembled on site. In the case of hanging fill packs, one sheet at a time must be placed on the support tubes. This means that the installers must remove individual film fill sheets which have been shipped nested, one at a time from the packing crate. These film fill sheets are then elevated to the point of installation where they are sequentially placed over support tubes in proper orientation one with respect to another. Obviously, in view of the flexibility of the film material and the overall area of each of the film fill sheets, wind velocities are a major factor in the construction process. In fact, film fill sheet installation must be halted when the wind velocity exceeds a value determined and established as a standard by experience.
To save hanging fill pack erection time at the tower site, there has been an effort to glue the film fill sheets into packs at ground level prior to installation on the tube supports. This is expensive, as previously pointed out, and can only be justified on short construction schedules.
SUMMARY OF THE INVENTION
Therefore, what is needed and has not been previously available is a multiple sheet film fill that (a) ships with nested sheets to the assembly or construction site to minimize shipping costs by avoiding shipping of air, (b) minimizes handling of individual sheets during the fill installation in the tower, and (c) avoids the expense of gluing of the sheets one to another on site.
In particular, this unfulfilled need is now satisfied by the provision of a bundle made up of a number of liquid film fill sheets in which every other sheet is shingled in order to permit the sheets to be nested for shipping. Each of the film fill sheets has area-increasing surface patterns on opposite faces thereof. The surfa
Kinney, Jr. Ohler L.
Mockry Eldon F.
Baker & Hostetler
Bushey C. Scott
The Marley Cooling Tower Company
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