Gas separation: processes – With control responsive to sensed condition – Temperature sensed
Utility Patent
1999-04-02
2001-01-02
Smith, Duane S. (Department: 1724)
Gas separation: processes
With control responsive to sensed condition
Temperature sensed
C055S354000, C095S019000, C095S025000, C095S026000, C096S420000, C096S421000, C096S423000, C096S429000
Utility Patent
active
06168646
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to flow rate control of temperature control fluids.
BACKGROUND OF THE INVENTION
Many types of equipment rely, in operation, upon temperature control to ensure that the equipment operates within accepted temperature ranges at which temperature effected breakdown or deterioration of the whole or parts of the equipment. cannot, or is unlikely, to occur. Different methods and technologies are brought to bear upon temperature control for the above purpose, e.g. the use of non-enclosed temperature control fluids such as the passage of air entrained through flow passages of equipment, closed circuit fluid flow heat exchange, and the use of solid heat conductive and heat radiating structures.
One problem being considered herein is concerned with flow control of temperature control fluids in use of equipment and in which the fluid is non-enclosed, e.g. ambient air. More precisely, the problem results from the necessary filtration of air before this enters equipment in order to prevent undesirable, i.e. operationally damaging material, such as duet or other particles, from passing into the equipment. For instance, in the use of electronics equipment or some electrical equipment, it is critical to prevent ingress of airborne particles into the equipment as these may accumulate in time upon conductive surfaces with a potentially heat damaging effect, may bridge between conductive surfaces thereby shorting out circuitry, or may introduce or accelerate corrosive conditions.
While the introduction of filtering materials into equipment such as electrical or electronic equipment, effectively filters out damaging materials temperature problems may result as use of any particular filter continues. If a filter is being used efficiently, it progressively becomes contaminated with the filtered out materials thereby progressively clogging the filter. Where the filter is being used to filter a temperature control fluid passing through the equipment, clogging of the filter is attended by reduction in flow rate of the fluid which then effects increase in temperature.
Where the equipment is used indoors, the changing state of the filter may be monitored relatively simply to enable it to be changed for an unused filter at any appropriate time. However, where equipment is being used outdoors, the problem is no longer simple. Certain types of equipment, e.g. electronics equipment such as used in the telecommunications industry, needs continuous operation. The extent of the useful life of a filter when incorporated into outside equipment cannot be assessed, because from one item of equipment to another located at different sites, the filtering requirements may be widely different. Also at each site, the filtering requirements may also vary widely dependent upon weather and seasonal or other environmental conditions. The latter may vary because of change in wind direction when industrial contamination is being generated in a specific direction from the equipment. Seasonal variations may result, when equipment is located close to an agricultural site when, at various times, dust, Seeds or other plant materials become airborne.
As may be seen, therefore, outside filters particularly cannot be changed strictly on a timed basis. Outdoor equipment is provided, because of this, with alarm systems which notify a central office when filters become clogged. At such times, immediate attention is required by maintenance personnel. If such attention is not provided within due time, then equipment which is still necessarily in use may overheat thereby resulting in breakdown. This may be extremely expensive and inconvenient.
SUMMARY OF THE INVENTION
The present invention seeks to provide equipment which will require minimal filter maintenance while also minimizing the possibility of equipment breakdown.
According to one aspect of the present invention, equipment is provided having a housing, a fluid flow passage for flow of a filtered temperature control fluid through the housing, a length of filter material having a length portion extending across an upstream end of the flow passage for filtering undesirable material from the fluid, means for causing fluid flow through the length portion of the filter material and along the flow passage, filter advancement means, and control means actuable when an undesirably low rate of fluid flow is achieved through the length portion of tube filter material, to operate the advancement means so as to advance the length of filter material for a distance longitudinally to move at least some of the length portion from the upstream end of the flow passage and move unused filter material across the upstream end of the flow passage thereby to increase fluid flow through the filter material above the undesirably low rate.
It follows, from use of equipment according to the above invention, that when the undesirable low rate of fluid flow is determined to occur at still acceptably high temperatures inside the equipment, i.e., below such high levels as to result in equipment failure, overheating and resultant breakdown cannot occur so long as unused parts of the filter material are still available. In these situations, the equipment will continue to operate within satisfactory temperature ranges without requiring filter maintenance visits from personnel. In anticipation that the length of filter material will eventually have been advanced to a position where little or no unused material remains upon the length, alarm signaling means may be employed to provide a warning to a central office that the length of filter material needs replacement.
The filter material length may be short thereby allowing the advancement means to be advanced only once to move unused filter material across the fluid flow passage. However, for convenience and on a practical basis, the filter material length should be such as to provide for a substantial number of operations of the advancement means. The maximum distance along the filter material length may hence be determined by the available space for used and unused parts of the length in relation to the particular equipment under consideration.
In practical arrangements, the filler material is flexible and the advancement means includes a roller device for the take-up of used filter material. The unused filter material may he stored, for instance, in a stack with layers of the stack interconnected by material. However, it is convenient to provide two roller devices, e.g. one roller device for holding and taking up used filter material and another roller device for holding and releasing the unused filter material. Each or one of the roller devices may comprise two parallel spaced rollers with the used or unused filter material, as the case may be, extending around the two rolls and from roll to roll. This arrangement could be particularly useful, where necessary space requirements exist, when an extremely long length of filter material is employed. However, in a simple arrangement, each roller device comprises a single take-up or give-up rolls.
In roller device arrangements, the advancements means in practice also includes means for driving the roller device for take-up of used filter material.
The control means for operation of the advancement means may include any means which, in some way is affected by clogging of filter material extending across the upstream end of the flow passage so as to effect such operation. For instance, in a preferred arrangement, it is recognized that where the means for causing fluid flow comprises fan means having at least one fan downstream in the flow passage from the length portion of the filter material, a drop in pressure occurs between the fan and the filter material as clogging proceeds. In this preferred arrangement, the or each fan is expected to be driven at a constant speed when employing unused filter material. However, there will be a progressively increasing pressure drop as filter clogging increases and the pressure drop is accompanied by a drag on the fan blades with resultant
Craig William L.
Moss John S.
Foley & Lardner
Nortel Networks Limited
Smith Duane S.
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