Rotary kinetic fluid motors or pumps – Working fluid bypass
Reexamination Certificate
1999-03-26
2001-03-27
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Working fluid bypass
C415S027000, C415S056100, C415S169100, C029S888021, C029S888024
Reexamination Certificate
active
06206632
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This is related to the concurrently filed applications of the present inventor and entitled “System and Method for Heating or Cooling Contents of Flexible Containers”, “Nozzle Assembly”, and “System and Method for Heating and then Cooling Contents of Flexible Containers”. The entire contents of each of these applications are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention is directed to pumps and to methods of retrofitting pumps and particularly centrifugal pumps useful in systems for heating and cooling contents of flexible containers.
Many foodstuffs today, such as tomato paste, orange juice, crushed pineapple and diced tomatoes, are cooked and filled hot into flexible bags. The containers with the heated product (foodstuffs) must then be cooled for subsequent handling and storage.
An example of a system of the prior art for cooling contents of flexible bags is shown in
FIG. 1
generally at
70
. Referring thereto, the bags
72
enter the open-plastic belt conveyor
74
at one end into a first cooling station as shown generally at
76
. Station
76
is shown in isolation in FIG.
2
. The bag
72
is in a bath
78
of cooling water up to about its mid point. Overhead sprayers
80
spray cooling water on the tops of the bags
72
. The bag
72
is conveyed by the mechanical action of the conveyor
74
to a gate
82
at the forward end of the station.
The gate
82
is formed by three stacked, upwardly rolling rollers
84
,
86
,
88
. The actions of the conveyor
74
and the rollers
84
,
86
,
88
cause the bag
72
to rotate or turn over, as shown by arrow
90
, about an axis generally perpendicular to the travel direction of the conveyor
74
to thereby partially mix the bag contents and to expose the bottom surface of the bag to the cooling water from the sprayers
80
. The gate
82
is then pivoted down as shown by arrow
92
, and the bags
72
are conveyed together to the next station for a subsequent cooling process, and so forth through the twelve or so stations.
There are a number of problems with the prior art system
70
. One is that the overall process of system
70
is slow. It takes about forty minutes to cool the contents of the bag
72
from two hundred degrees down to below one hundred and twenty degrees Fahrenheit. Another problem is that the bags
72
, and particularly when they are underfilled, occasionally get caught in the rollers
84
,
86
,
88
and break, spilling their contents. A further disadvantage of the prior art system
70
is that it occupies a large amount of floor space since it is approximately seventy feet long.
Other systems for cooling or heating the contents of flexible containers are shown in the following U.S. Pat. No. 4,384,463 (Rica et al.), U.S Pat. No.5,009,150 (Andersen) and U.S Pat. No. 5,370,174 (Silverstrini et al.). The contents of each of these patents and all other patents mentioned in this disclosure are hereby incorporated by reference in their entireties.
SUMMARY OF THE INVENTION
The present invention is directed to providing an efficient means for cooling (and/or heating) contents of flexible containers or bags. The bags with their hot contents are dropped into an infeed end of a trough containing cooling water. The bags are advanced from one station to the next in the trough by the periodic actuation of a fluid jet conveyor at the inlet end of the trough. After the bags are advanced to their respective next stations the fluid jet conveyor is turned off and the fluid nozzle system is turned on.
The fluid nozzle system includes a first series of nozzles on one side of the trough and directed into the trough and a second series of nozzles on the other side of the trough and similarly directed into the trough. The first series of nozzles are disposed in a horizontal plane spaced about four inches above the horizontal plane of the second series of nozzles. Thus, when the bag reaches the next station and the nozzle system is turned on, the water from about the five or so nozzles of the first series impinge against the adjacent side of the bag about two inches above the midline of the bag, and the water from the five or so nozzles of the second series impinge on the opposite side of the bag, about two inches below the midline of the bag.
The two sets of opposing and offset nozzles have two actions on the bag. First, they impinge and push in on the side of the bag, about twelve inches, for example, on each side. This “massaging” action causes the central contents of the bag to move away from the center of the bag and towards the side of the bag thereby promoting the transfer of heat from the central contents of the bag to the cooling water at the surface of the bag. Second, they cause the bags to rotate about an axis generally parallel to the axis of the trough. This rotation motion in the bath of cool water in the trough also assists in the cooling of the bag's contents. It is additionally within the scope of the invention to orient the nozzles so that the bag is rotated in a clockwise direction at one station and an opposite counterclockwise direction at a next station in the trough.
The bags generally abut one another end-to-end as they travel from station to station in the trough of the present system, and no gates or other structures separates them from the adjacent bags. The movement of the bags into, along and out of the trough is now described with respective bags in the three active stations in the trough and one in the ramped station (“dead zone”) at the exit end of the trough and with the offset nozzle system on. A detector at an infeed station above the trough input end detects the arrival of a hot filled bag. When this is detected the flow of the cooling water is switched from the offset nozzle system to the fluid jet conveyor and the first extraction conveyor is turned on. The bag at the ramped station is pushed onto the first extraction conveyor and conveyed away on it. The three bags in the trough move to their respective next stations by the action of the fluid jet conveyor. A detector generally at the outlet end of the extraction conveyor detects the arrival of the extraction bag and turns the first extraction conveyor off.
The first infeed station is then empty, and the hot filled bag detected by the infeed station detector slides down into the first infeed station. Thus, bags are now in the three active stations and in the ramped station. The bag at the ramped station advantageously acts as a plug or a soft gate, blocking the further advancement of the bags relative to the trough. The infeed station detector detects that no hot filled bag is at or nearly at the infeed station, and causes the cooling water to switch and flow to the nozzle system and not the fluid jet conveyor. The three bags in the three active stations are thereby massaged and rotated. When the infeed station detector detects the arrival of another hot filled bag, the process starts again.
A centrifugal pump pumps the cooling (or heating) fluid (water) from a cooling tower to a butterfly valve which directs the fluid flow to either the fluid nozzle system or the fluid jet conveyor. A bleed tube at the exposed eye of the impeller bleeds air out of the pump. The “exposed eye” is defined when the impeller center can be seen when looking down the suction line in the direction of liquid flow. U.S. Pat. No. 4,981,413 calls it the “center of the pump impeller”. (In contrast, see U.S. Pat. No. 3,575,521.) A low pressure check valve prevents air from being sucked into the pump through the bleed tube. Bleeding the pockets of air in the pump prevents the pump from losing its prime.
This pump arrangement invention, in addition to being used in the present heating/cooling environment, can be used aboard ships where the pump suction may become exposed in a rolling sea. It can be used generally in any application where the supply level is difficult to control and the pump loses its prime when air gets into the suction line.
An exemplary method for retrofitting such a pump in
Look Edward K.
McDowell Liam
Peacock Myers & Adams
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