Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a mobile unit for condition-
ing air in enclosed spaces. More specifically the present
invention relates to a mobile air heater, conditioner and purifier.
It is often necessary to control the atmospheric
conditions in enclosed spaces while working in these spaces.
For example, underground work chambers are provided for servicing
underground utility lines within these chambers. The chambers,
when not regularly used, become very damp and cold. In addition,
toxic gases collect in the chambers. In the case of utility
lines, there is the requirement to splice cables or join pipes
which requires the use of heat resulting in fumes, smoke and
other toxic gases which must be removed. In order to work com-
fortably in these chambers, it is necessary to purify, and often
replace the air for the entire time a service man is in the
chamber. It is also necessary to either heat, cool or dehumidify
the air. Other examples of enclosed spaces requiring controlled
atmospheres include aircraft, transport trailers, radar
stations and mining tunnels.
It is known to provide portable pieces of equipment to
condition the air in these chambers. For example, it is known
to provide portable blowers to ventilate the chambers. These
blowers may also heat the chambers. However, the handling of
these blowers for transportation and set-up is quite labour-
intensive. In addition, several different types of equipment,
also requiring labour intensive handling may be needed if the
air in the chambers is to be filtered, cooled, or dehumidified.
To avoid the handling of one or more pieces of port-
able equipment it is known to install conditioning units in a
work trailer. The trailer is then driven to the site and
connected, along w~th its conditioning units, directly to the
work chamber. Such a unit is shown in U.S. patent 3,914,955
issued to McCullough. Since the conditioning units are permanently
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installed in the work trailer only the work trailer need be
handled, thereby eliminating individual handling and set-up of
the conditioning units.
The known trailer unit has certain disadvantages,
however. Since it incorporates a work area, the trailer is
large and bulky and thus awkward to handle. Consequently, a
lot of time must be spent in setting up the trailer at the
work site, and furthermore, many underground chambers do not
have sufficient space above for setting up a trailer of this
type. The access openings to such a chamber are often against
a wall, or have different spacings between access holes making
connection to the trailer all but impossible.
Another disadvantage of the known trailer unit is the
complexity of the conditioning means. Since both the work
chamber and the work area in the trailer are to be conditioned,
no simple in-line flow-through system can be employed for
circulating and replenishing the air. The complex system em-
ployed makes the trailer relatively expensive.
It is further noted that no provisions are provided
in the trailer unit for handling any toxic gases which may have
accumulated or are produced in the work chamber. These toxic
gases would merely be recirculated through both the work chamber
and the work area in the trailer creating an unpleasant, and
possibly dangerous working environment.
It is the purpose of the present invention to provide
a compact extremely mobile unit with means thereon for condi-
tioning air in enclosed spaces.
It is a further purpose of the present invention to
provide a mobile conditioning unit which more thoroughly con-
ditions the air, including removing toxic gases from the air, as
compared with known units, and which do not filter the air other
than by standard throw-away type filters.
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In accordance with the present invention there is
provided a compact trailer unit having an open platform on which
the necessary conditioning units are mounted. The ccnditioning
units include heating, cooling, dehumidifying and purifying
means connected in series on the platform with duct means.
Flexible conduits are employed to connect the duct means with the
work chamber thereby eliminating the need to exactly position
the trailer unit. Heating can be provided by means of natural
gas, propane gas or electrical power.
In a preferred embodiment a heat pump is provided on
the trailer. The heat pump is a basic air conditioner operating
in reverse. The unit is installed to eliminate the need for
combustion by using the reversing valve method known to those
skilled in the art of heat pumps. The energy conservation aspect
of the unit is greatly enhanced by use of the heat pump.
The trailer unit is small enough and compact enough to
be easily handled and positioned, even in tight spaces. All
the conditioning units are readily accessible for maintenance,
servicing and operation. The electrical power to the unit can
be externally supplied. Alternatively, an electrical power
generating source, such as a gasoline or diesel generator, can
be mounted directly on the open platform. Heating fuel, in the
form of gas, propane or natural, can also be carried on the
platform. The invention provides a self-contained, mobile, con-
ditioning unit which is relatively inexpensive to construct and
maintain yet easy to handle and set up.
The present invention provides a mobile unit for use
in conditioning air in a remote enclosed space having at least
one opening therein, the unit being in the form of an open
trailer comprising, an air entry having a purifying means to
remove toxic gases and filter airborne particles, cooling means,
dehumidifying means and heating means, ducting system from the
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air entry connecting the purifying means, cooling means, de-
humidifying means and heating means to an air exit, fan means
within the ducting system to circulate air from the air entry
to the air outlet, and two removable flexible conduits for
connecting the air entry and the air exit to the enclosed
space.
In drawings which illustrate embodiments of the
invention,
Fig. 1 is a perspective view of the mobile unit.
Fig. 2 is an elevational view, in partial section,
showing the unit used for conditioning a remote chamber.
Fig. 3 is a block diagram indicating the air flow
through the unit.
Referring now to Figs. 1 and 2, the mobile unit 10
has a platform 11 mounted on a pair of wheels 12. The wheels 12
are located off the centre of the platform. The trailer hitch
13 is mounted on a front support frame 14 projecting from the
front end of the platform ll. _A front support stand 15, which is
adjustable in height, supports the front end of the platform 11
when the unit 10 is parked in operating position. The front
support stand 15 can be raised by suitable means (not shown) when
the unit 10 is to be moved. In another embodiment, the front
support stand 15 may be a wheel for moving the trailer by hand.
A levelling stabilizer 16 such as a jack, is provided at each
side of the rear of the platform 11 to help level the unit 10
when parked on uneven ground.
The air conditioning devices are mounted on the platform
11. These devices are installed in line from an air entry 20
as shown in Fig. 3. First a pre-filter 21 removes any large
.0 particles entering the conditioner, then chemical absorbent filters
22 remove odors and toxic gases. These filters 22 are disposable
and may be replaced at regular intervals depending upon operation
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of the unit. In another embodiment, the chemical absorbent
filters 22 may be replaced by electrostatic filters to remove
all airborne particles in the air,
The air then passes through an air cooler 25 having
coils cooled by a compressor 26 located further on in the system,
A water eliminator 27 is next in line to remove moisture in the
air, A drain 29 from the water eliminator 27 collects the
condensed water and disposes of it on the ground,
An air circulating fan 30 is provided in a single duct
unit 31 as shown in Figs, 1 and 2, An additional air inlet 32
having adjustable louvers therein provides for fresh air to be
drawn into the fan 30 and circulated through the unit, Fresh
air varying from about 8 to 30~0 of the total circula$ing air may
be introduced into the unit, Additional fresh air ensures that a
similar amount of air is exhausted and not recirculated, The
adjustable louvers or damper may be manually operated or auto-
matically operated from a temperature controller in the air duct 31.
The compressor 26 for the cooling coils 25 is shown
located in the air duct 31 at this point to act as a heat pump
and to save energy by heating the air at the compressor and cool-
ing it prior to the water eliminator, In some cases the heat from
the compressor 26 can eliminate the need for the heater 40. In
another embodiment the compressor may be located outside the duct
~1 and heat only the environmental air, depending upon the tem-
perature of the ambient air, For instance in a hot climate, there
would be no need to have the compressor 26 in the air duct 31,
A gas fired heater 40 also in the air duct 31 heats the
air before it reaches the air outlet 41, Containers 42 of gas
are stored at one end of the platform, A gas gauge (not shown)
is provided to indicate the quantity of gas remaining in the
containers 42,
In one embodiment an exhaust fan 42 is positioned
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before the air outlet 41 in the system after the heater 40
as shown in Fig. 3, The exhaust fan 42 may be used inter-
mittently to remove excessive fumes, The exhaust fan 42 is
connected directly to the outlet duct and has manual or
motorized dampers, The exhaust fan 42 is shown positioned
before the outlet, but may also be located at the air inlet 20,
A first flexible conduit 50 is provided for connection
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to the air inlet 20 of the unit 10. A suitable quick connect
coupling 51 is employed to connect the conduit 50 to inlet 20.
A second flexible conduit 52 is provided for connection to the
air outlet 41 of the unit 10. Again, a suitable quick connect
coupling 53 is employed to connect the conduit 52 to the outlet
41. The conduits 50, 52 can be stored in suitable holders on
the platform, disconnected from the air inlet 20 and air outlet
41, during travel or storage. The conduits 50, 52 are only
connected to the unit 10 during use.
An electrical power connection 60 is provided on the
unit 10 for connection to an external source of power. Suitable
wiring is provided on the unit to connect the power connection
60 to the motors for the fan 30 and the compressor 26 for the air
cooler 25 In another embodiment, a gasoline or diesel powered
generator may be mounted on the platform 11 to provide the
necessary electrical power.
In use, as illustrated in Fig. 2, the unit 10 is towed
to the site where it is to be used, such as an underground
utility service chamber 70. Such chambers usually have at
least two access openings 71 to the surface 72 which openings are
normally closed by covers. Utility cables or pipes 73 pass
through the chamber 70 and connections, or changes in connections,
in the cables 73 can be made in the chamber 70. To provide
suitable working conditions within the chamber 70 the unit 10
is first positioned close to the chamber and levelled. The
flexible conduits 50, 52 are then removed from their storage area
on the platform and connected to the air inlet 20 and air outlet
41. The free end of the inlet conduit 50 is placed in one
opening 71 of the chamber 70 and the free end of the outlet
conduit 52 is placed in the other opening 71 and both conduits
are sealed to avoid contamination by outside air The unit 10
is plugged into a source of electrical power or else the motor-
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generator is started.
In another embodiment the inlet conduit 50 and outlet
conduit 52 are connected to a concentric diffuser which may be
installed within the chamber. In this manner both conduits can
pass through a single access opening.
During operation, the fan 30 circulates air from the
service chamber 70 through the un~t 10 via the conduits 50, 52.
Toxic gases and/or odors are removed from the circulating air in
the purifying system. Thermostats in the air duct determine
whether the air should be heated or cooled, and this is automati-
cally carried out. Similarly a humidistat determines the
humidity of the air and whether or not the dehumidifier is
required. The speed of the fan may be varied to change the flow
of air through the unit. It is required to change the air in
the chamber preferably 20 times an hour and for standard size
chambers the fan and duct size are designed accordingly.
To economize on cooling, it is sometimes preferred to
bring in as much as 30% of outdoor air into the unit. The unit
operates at ambient temperatures as low as O~F and maintains
a working temperature of above 60F within the chamber. Heating
capacities can vary from about 80,000 to 372,000 BTU or higher.
Cooling capacities can vary from about 36000 to 180,000 BTU or
higher.
The operation of the unit is controlled from operating
controls (not shown) where variable controls enable temperature
and humidity to be selected. The controls include mechanical
and electrical devices preferably solid state, to maintain
temperature and humidity at preset levels. Monitoring devices
such as temperature and humidity recorders may also be provided.
Various changes may be made to the conditioning unit,
for instance wherein a gas heating system is disclosed, this
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could be replaced with an electric or heat pump heating system.
Controls can vary from standard controls to sophisticated solid
state controls.
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The units are insulated against sound and condensation
and in one embodiment a three speed fan is employed, Time
elapsed meters are fitted to the control panel to record the
number of hours the unit is operated. In another embodiment
water cooled units may be installed connecting the city water to
avoid the necessity of a condensor for the cooling coils. Air
flow flexible conduits are made from flame resistant materials
and can be made in the range of about 8 - 18 inches diameter or
more.
