Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/70—Drying or keeping dry, e.g. by air vents
  • E04B1/7015—Drying or keeping dry, e.g. by air vents by heating the ambient air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
  • F26B21/001—Drying-air generating units, e.g. movable, independent of drying enclosure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
  • F26B21/06—Controlling, e.g. regulating, parameters of gas supply
  • F26B21/08—Humidity
  • F26B21/086—Humidity by condensing the moisture in the drying medium, which may be recycled, e.g. using a heat pump cycle

Definitions

• This invention relates to dehumidifying apparatus and is more particularly concerned with cooling or refrigeration dehumidifiers.
• Dehumidifying apparatus is used to reduce the amount of water vapour in the atmosphere and thus is frequently employed to dry out flood damaged buildings or other enclosed areas which have become damp or soaked with water.
• Dehumidifying apparatus can shorten the drying time of materials including building structures (for example bricks, concrete, timber etc. ) and any other materials having higher moisture content than is required.
• Such apparatus can be used to reduce the humidity level in an enclosed area in order to reduce the activity level of moisture related corrosion and to prevent deterioration, due to excess moisture absorption, for example of stored items.
• Dehumidifying apparatus presently available include cooling or refrigeration dehumidifiers and desiccant humidifiers. Both these types of dehumidifiers tend to have certain disadvantages.
• Refrigeration dehumidifiers are much less costly than the desiccant type and generally have low cost and low power consumption characteristics, but are only efficient within a specific temperature range. If the air surrounding the dehumidifier is already cold then the refrigeration dehumidifier will not work well in condensing out water from air which is already cold. Thus, refrigeration dehumidifiers operate within a limited temperature range and additionally they tend only to provide a limited air movement which tends to be in ⁇ sufficient on its own for the dehumidifying process to be carried out reasonably quickly. Desiccant dehumidifiers may not have some of the drawbacks which tend to be associated with refrigeration dehumidifiers (i.e.
• the same limited temperature range for operation does not apply) and they tend to be more efficient at low humidity levels.
• the cost of a desiccant dehumidifier may be four or five times that of a refrigeration dehumidifier of similar size and capacity and, additionally, the desiccant dehumidifier requires specialist maintenance and attention, there being much less requirement with refrigeration dehumidifiers which are generally reliable as well as being much less expensive.
• dehumidifying apparatus in conjunction with other devices such as heaters and fans in order to attempt to improve the overall de-humidifying or drying-out process but the overall efficiency still tends to be lower than need be the case.
• dehumidifying apparatus in the form of a portable or transportable unit comprising a cooling or refrigeration dehumidifier in combination with a pressure developing fan or impeller.
• the pressure developing fan or impeller is arranged so that it does not directly interact with the working components of the refrigeration dehumidifier.
• said fan or impeller is arranged in a compartment within said unit (preferably towards the bottom of the unit and underneath the dehumidifier) and, preferably, a separate air intake and separate air outlet is provided for the fan/impeller.
• a heater is also provided in said unit (this heater is preferably located in the flow path from the fan/impeller ) .
• the unit is, preferably provided with duct means to convey the air from the air outlet of the impeller to a location somewhat remote from the unit itself.
• the operation of the components of the refrigeration dehumidifier is unaffected by the inclusion of a fan/impeller and/or heater contained within the same unit, so that, advantageously, no new design or maximised operation parameters need to be worked out for the refrigeration dehumidifier.
• a standard existing refrigeration dehumidifier can be utilised and incorporated into said unit with the fan/impeller and/or heater.
• the refrigeration dehumidifier, the fan/impeller (and heater where provided) may all be powered from a single power source and via a standard 13 amp plug connected into a standard 240 volt 20 amp ring main.
• the air flow from the pressure developing fan/impeller is positioned advantageously in such a manner that it does not interfere with or upset the predetermined balance between air flow and condensing surfaces in the refrigeration dehumidifier. Instead, a balance is provided between the capacity of the dehumidifier, the heat output (where the heater is provided) and the additional air movement, tc provide seemingly optimised drying conditions.
• duct means is provided to carry air from the fan/impeller to a location remote from the unit itself, positive air pressure points are created away from said unit thereby improving air distribution further and allowing the air returning to the negative pressure inlet points of the unit to slow to a speed which will not interfere with the working of the refrigeration dehumidifier.
• duct means is provided as aforesaid this would usually comprise at least two sections of flexible ducting to convey air from the fan/impeller to spaced locations away from the unit itself.
• the fan/impeller is a backward curved centrifugal type noted for quiet operation and pressure developing characteristics which, advantageously, does not require any specially shaped casing for efficiency.
• a heater may be of about 2 kilowatts for a domestic unit (refrigeration dehumidifier having a compressor with approximately one third h.p. capacity).
• the operation of the refrigeration dehumidifier, fan/impeller and/or heater may be controlled from a control panel (preferably located on said unit) or at least inter-related control means may be --.
• a switch interlock may be provided to prevent the heater being used without the fan and/or a separate heater auto resetting over temperature switch may be provided to prevent overheating 0 in the event of failure of the fan/impeller or in the event of restriction of air passage through the unit.
• the unit comprises an internal humidistat preset to prevent overdrying and an internal 5 preset thermostat to control the temperature of the drying area.
• a humidistat may be provided for controlling external humidity.
• the unit may be no wider than 750 mm 0 and no higher than 1,500 mm.
• a heater it will be preferably settable to a plurality of heat output levels since ambient temperature conditions are variable.
• the heater may be an open, wire-wound type with an electrical centre tapping given to heat options.
• said pressure developing fan or impeller is arranged to interact with the working of the refrigeration 5 dehumidifier.
• This design of dehumidifying apparatus will usually entail a large scale industrial unit where the design and operating parameters for the refrigeration dehumidifier are not as critical as with smaller, domestic scale equipment.
• the apparatus may be of 5 h.p. capacity. It is believed that such a unit could be constructed at somewhere around one fifth of the price of desiccant dehumidifiers of a similar scale.
• the unit may be provided with an air intake into the refrigeration dehumidifier as well as two side air intakes into separate fan/impeller units operating to convey air to heaters before driving the air to air outlet means.
• Air issuing from the air outlet means may be a combination of heated air from the impellers and dry air from the refrigeration dehumidifier.
• the power consumption of the apparatus may be balanced electronically to suit required conditions, ambient conditions and power availabity.
• the unit will be arranged to operate from a three phase power supply with 9 kilowatt and 14 kilowatt options.
• a method of drying or dehumidifying a room or enclosed area comprising operating a refrigeration dehumidifier in combination with a pressure-developing fan or impeller in such manner that the convection cycles of the dehumidifier and of the fan/impeller are mixed in order to set up a controlled drying cycle.
• the air from the fan/impeller is heated and, preferably, the heated air is carried to an outlet point or points away from the refrigeration dehumidifier so that positive air pressure points are created away from the refrigeration dehumidifier in order that air returning to negative pressure inlet points to the dehumidifier will be slowed down.
• FIGURE 1 is a diagrammatic representation of the operating • cycle of a known type of refrigeration dehumidifier
• FIGURE 2 illustrates the operating effect of the refrigeration dehumidifier of FIGURE 1 used in conjunction with a separate heater and fan
• FIGURE 3 illustrates the operating cycle of de ⁇ humidifying apparatus in accordance with the present invention
• FIGURE 4 is a sectional schematic side view of the dehumidifying apparatus shown in FIGURE 3;
• FIGURE 5 is a more detailed three dimensional schematic view of the dehumidifying apparatus;
• FIGURE 6 is a view similar to FIGURE 5 but shows a larger modified embodiment of the dehumidifying apparatus
• FIGURE 7 shows a three dimensional schematic view of a very substantially modified embodiment of dehumidifying apparatus which is for use on an industrial scale.
• FIGURE 1 of the drawings illustrates schematically a refrigeration dehumidifier 1 which is generally of a known type. Air is circulated through the device which sets up a convection cycle as illustrated by the arrows passing into the air inlet A and through the air outlet B of the dehumidifier.
• the dehumidifier 1 is provided with an air-cooling arrangement (not shown) and an evaporator (not shown) which condenses out water vapour from the air, said water vapour being fed by a condensate outlet hose H into a storage container S.
• the refrigeration dehumidifier operating in the room or enclosed space R provides limited air movement (as illustated by the arrows of the convection cycle) and, since the dehumidifier operates by cooling the air in order to extxact the condensate it is only operable within a limited temperature range.
• FIGURE 2 illustrates what happens when the refrigeration dehumidifier 1 is used in conjunction with a heater 2 and with a fan 3 in the same enclosed space.
• the dehumidifier 1, heater 2 and fan 3 set up their own convection cycle as depicted by the arrows in the FIGURE.
• the inclusion of the fan 3 and heater 2 in the same enclosed space with the dehumidifier 1 slightly improves drying rates but because each convection cycle is separate the overall efficiency is still low.
• Heaters when used alone, assist in the evaporation of moisture from materials but have no means of disposing of the moisture which is in the air and fans provide good air movement which can speed up the drying process, but once again have no means of disposing of moisture in the air.
• FIGURE 3 shows de-humidifying apparatus 101 in accordance with the present invention, which is utilised in an enclosed area and illustrates the mixed convection cycle (illustrated by the arrows ) set up by the apparatus.
• the apparatus 101 is shown in more detail in FIGURES 4 and 5.
• the apparatus 101 has an upper section 102 which corresponds basically with a standard cooling or refrigeration dehumidifier. This works in a known manner and, therefore, will only be described briefly.
• the dehumidifier 102 has an air inlet 103 in which air is drawn by a fan f before being passed through outlet 105 (see the arrows through the dehumidifier section 102 in FIGURE 4) .
• a compressor C is provided which runs coolant through cooling coil 104 in order to cool air incoming through inlet 103.
• An evaporator e is provided in the flow path to the fan f and water is condensed out from the air being drawn through the air inlet 103 and passed down the condensate outlet hose H into a container S in known manner. Air from which moisture has been extracted is fed out of the dehumidifier through outlet 105.
• the unit 101 as shown in FIGURES 2 to 5 is a one third h.p. unit and, in this size of unit there is an important balance to be maintained between the dehumidifier air throughput and the cooler surface area of the cooling coil 104 and temperature. Therefore, in order not to upset this balance (but to improve the efficiency of the dehumidifying process) the unit is provided with a centrifugal, pressure developing fan or impeller F, which is housed in a separate compartment 106 at the bottom of the unit 101. As should be clear from FIGURES 4 and 5 a dividing baffle or wall 107 is provided to separate the refrigeration dehumidifier 102 from the compartment 106 housing the fan F.
• a separate air inlet 108 is provided for the fan F which draws air into the compartment 106 and delivers the air to a heater 109 ( 2 kw in this case) before the air is fed to flexible air distribution ducts 110.
• the fan F itself is chosen to be as quiet as possible and is a rotating fan which is of a backward curved centrifugal type noted for quiet operation and pressure developing characteristics. Additionally, this design of fan does not require any specially shaped casing for efficiency.
• the heater 109 is an open, wire-wound type with an electrical centre tapping giving two heat options. Heat output selection is desirable because of variable ambient temperature conditions.
• Air from the heater 109 is delivered to two outlets 111 (see FIGURE 5) on the front of the apparatus 101 and the flexible ducts 110 (2 ducts shown) can be connected to the outlets 111.
• the air inlet 108 is on a fan inlet negative pressure side and the air outlets 111 are on a positive pressure side.
• the connection of the flexible ducts 110 has the effect of moving the air outlet of the fan F and therefore the positive air pressure points away from the unit 101 and thus improves air distribution. Spacing the air outlet points from the fan away from the unit 101 allows the air returning to the negative pressure inlet points of the unit (more particularly to inlet 103 ) to slow to a speed that will not interfere with the operation of the dehumidifier 102.
• FIGURE 3 shows a general flow path for the mixed convection cycle in which one of the air outlet points of one of the ducts 109 is trained under the floor boards of the room R in order to help dry out damp in the walls of the room.
• Warm air under pressure is forced out of the ends of the ducts 110 and mixes with damp air being drawn through the fan inlet 108 and also mixes with damp air being fed through the inlet 103 to the dehumidifier.
• Dry air from the dehumidifier outlet 104 is circulated and mixed with the damp air and warm air (from ducts 110) into the dehumidifier inlet 103.
• the apparatus 5 101 encourages a good mix of dry air, damp air and warm air without affecting the operation of the dehumidifier 102.
• an internal humidistat (not shown) preset to prevent overdrying is positioned in the compartment 106 near the inlet 108 in the incoming 0 airflow.
• an internally preset thermostat (not shown) to control the temperature of the drying area is also positioned in the unit near the inlet 108 in the path of the incoming air.
• the dehumidifying apparatus 101 has a central control panel 112 to control the operation of the dehumidifier 102, fan F and heater 109 in interdependent manner.
• a switch interlock is provided to prevent the heater 109 from being used 0 without the fan Fand a separate heater auto resetting over temperature switch is provided to prevent overheating in the event of fan failure or restriction of the air passage. Additionally, provision may be provided for external humidity control by humidistat. 5
• the unit 101 is no wider than 750 mm and no higher than 1500 mm so that it may easily be transported from place to place and pass through standard size doorways.
• the unit operates from a single power C source and has a maximum power consumption not exceeding 13 amps, 240 volt A.C.
• the thermostat is set to stop the air from rising above a temperature of 30°C.
• the unit 101 is portable and transportable manually and by commercially acceptable transportation standards.
• the 5 unit can be controlled to prevent overdrying through low humidity levels and overheating of the drying area.
• the apparatus 101 can be set up to give approximately five air circulations per hour in a 100 of space.
• the apparatus 101 provides: (a) a proven dehumidifier arrangement 102 to collect moisture from the air, (b) a heater 109 to provide the operational temperature band for the dehumidifier 102 and to encourage moisture evaporation from materials, (c) a pressure developing fan to distribute the heated and dried air and to create air pressure variations, assisting temperature induced convection currents and thus setting up a controlled drying cycle, (d) a heater output capable of raising the temperature of the volume (as dictated by dehumidifying capacity) from 0°C to within the temperature band required by the dehumidifier to operate efficiently.
• An operation example for the apparatus 101 is as follows:
• the working temperature will be between 15°C to 30°C (optimum) and the heater requirement should be capable of raising 100 cubic metres from 0°C to 5°C to 30°C (in a sensibly sealed area).
• the addition of the flexible air distribution ducting 110 allows the effective drying area to be increased and makes the best use of the generation of positive and negative air pressures, these pressures being used to improve the drying cycle since conditions will be set at such that convection currents will move in order to equalise that pressure distribution.
• FIGURE 6 shows a modified embodiment of the dehumidifying apparatus 201.
• This apparatus is generally similar to apparatus 101 but is a 1 h.p. model.
• the operation of the unit 201 is similar to the operation of unit 101 but in this example two vertically arranged pressure developing fans F' (only one shown) are provided instead of the single horizontal fan F in apparatus 102. Additionally, two heaters 109' are provided rather than a single heater and the apparatus is provided with wheels W as shown. The heaters 109' are provided on each side of the unit 201. One of the heaters 109' is powered from the dehumidifier power supply circuit and the other is powered from a separate circuit.
• FIGURE 7 represents a much larger scaled unit in which there is an interaction between the air inflow to the humidifier and the air inflow to the fan and heater unit to thereby produce a mixture of air from the refrigeration unit from the heaters at the outlet side of the unit.
• FIGURE 7 shows a schematic arrangement for dehumidifying apparatus 301. The general scheme and placement of the various components of the apparatus should be generally evident from FIGURE 7.
• This large scale unit 301 will operate from a three phase supply and may have a 9/14 kilowatt option, but preferably will have variable power options from 5 to 14 kilowatts, and the power consumption will be balanced electronically to suit required conditions, ambient conditions and power availablility.
• any disclosure in this specification of a range for a variable or parameter shall be taken to include a disclosure of any selectable or derivable sub ⁇ range within that range and shall be taken to include a disclosure of any value for the variable or parameter lying within or at an end of the range.
• the dehumidifying apparatus may be utilised as an air conditioning unit.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Drying Of Gases (AREA)
• Drying Of Solid Materials (AREA)

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• 1990
  • 1990-02-16 GB GB9003571A patent/GB2242017B/en not_active Expired - Fee Related
• 1991
  • 1991-02-13 AU AU72346/91A patent/AU641475B2/en not_active Ceased
  • 1991-02-13 WO PCT/GB1991/000219 patent/WO1991012476A1/en not_active Application Discontinuation
  • 1991-02-13 EP EP19910903904 patent/EP0469111A1/de not_active Withdrawn

Non-Patent Citations (1)

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