Note: Descriptions are shown in the official language in which they were submitted.
2015672
-- 1 --
R~ POUND OF THB INVENTION
The present invention relates to an apparatus for thawing
fire hydrants and the like, and more particularly relates to an
apparatus which is designed to melt ice which has collected at the
lower end of the body of a fire hydrant.
The proper functioning of fire hydrants even in cold
(below freezing) temperatures is absolutely necessary. Cold
temperatures may result in the freezin7 of water within the body of
the hydrant a condition which may seriously impede or prevent the
operation of the hydrant. While the seal which stops the flow of
water to a fire hydrant is located well below ground, at the lower
end of a tubular body intended to feed water from water mains to
the hydrant, often such seals leak or water collects at the bottom
of the tubular body, on top of the seal, where it is prone to
freezing. When water freezes in this position, it may not be
possible to open the seal when it is desired to activate a fire
hydrant.
As a result, most urban centres exposed to cold weather
tend to inspect fire hydrants for such freezing during cold weather
conditions on a regular basis. When a frozen hydrant is located,
it is conventional to dispatch to that hydrant a truck with a large
water boiler mounted on it. Steam from the boiler is directed down
the hydrant body to melt the ice, and the condensed water from the
steam and melted ice are drawn out of the hydrant body by means of
a venturi mechanism mounted on the same hose which provides the
steam. Due to the high pressure nature of the boiler, these
2015672
-- 2 --
systems are difficult to maintain and can cause serious injury if
improperly maintained or operated. As well, they are not fuel
efficient and tend to use large amounts of energy, particularly in
very cold weather, since they must be run constantly.
Steam cleaning machines are known, for example for
cleaning machinery and equipment. These units may consist of
trailer mounted water reservoirs, with heaters and pumps mounted
thereon, whereby pressures of, for example 2760 KPa to 41400 KPa
(400 psi to 6,000 psi) are generated in hoses leading to a hand-
held release nozzle. The pressures generated in such systems are
extremely high, and the steam produced is adequate, for example to
clean an engine or large scale equipment. These prior art devices
however are unsuitable for thawing hydrants. Their pressures are
too high for safe and effective operation in the narrow confines of
a hydrant body. As well they do not operate well in cold
temperatures, the components tending to freeze or operate
sluggishly and ineffectively.
It is an object of the present invention to produce a
fire hydrant thawing machine which overcomes many of these problems
of these prior art devices.
SUNNARY OF THE lNv~ ON
In accordance with the present invention, there is
provided an apparatus for melting ice in fire hydrant bodies and
the like. The apparatus comprises a thermally insulated cabinet
with doors to provide access to its interior. Enclosed within and
2015672
-- 3
by the cabinet are a water reservoir tank, a water heater for
heating water from the reservoir to a predetermined temperature, a
delivery hose which extends from the cabinet into a hydrant body,
a circulating system and pump to deliver water to the delivery hose
at a predetermined pressure, a nozzle at the end of the delivery
hose to vaporize the water leaving the hose into steam, a suction
hose which extends from within the cabinet into the hydrant body,
a suction pump to be associated with the suction hose enabling
withdrawal of water collecting at the bottom of the hydrant body,
through the suction hose, and an appropriate power source for the
circulating pump and suction pump.
In a preferred embodiment of the present invention, to
prevent the water in the apparatus from freezing, means are
provided to recycle water from the reservoir through the
circulating system when water is not being used for thawing.
The apparatus according to the present invention operates
effectively even in cold weather, since all components are designed
to be operational in cold temperatures and the insulation of the
cabinet and the generation of heat within that cabinet keeps all of
the components of the system safe from freezing. The apparatus
works best at water pressures of about 690 KPa (100 psi) and a
water temperature of about 300 C (570 F). The equipment is less
bulky and more fuel efficient than the previously used steam boiler
apparatus and lends itself to be turned on and off, as required,
thereby being cheaper to operate.
The water heater unit can heat water to the required
operating temperature much faster than the previously used steam
201567~
-- 4
boilers which produce steam within the boiler units themselves. In
addition, the water heater produces water at the required operating
temperature both continously and indefinitely, provided the fuel
tanks and water reservoir are refilled.
The operation of the previously used steam boiler is like
a batch process. The boiler heats a quantity of water to steam and
that batch of steam is drawn off to thaw the hydrant. When the
batch of steam is depleted, the thawing operation must stop while
the boiler is refilled and another batch of steam is produced.
BRIEF DBBCRIPTION OF THE DRAWINGS
These and other objects and advantages of the invention
will become apparent upon reading the following detailed
description and upon referring to the drawings in which:
FIGURE l is a perspective view of a hydrant thawing
apparatus in accordance with the present invention;
FIGURE 2 is a plan view of the apparatus of FIGURE 1,
with the cabinet top broken away;
FIGURES 3 and 4 are respectively back and front elevation
views of the apparatus of FIGURE 1, with the back and front walls
of the cabinet respectively broken away;
FIGURE 5 is a schematic flow chart of the water heating
and steam generation system of the apparatus of the present
invention;
FIGURE 6 is a schematic view of the melt water drainage
system of the apparatus of the present invention; and
2015672
-- 5
FIGURE 7 is an example embodiment of a control panel lay-
out for the apparatus of the present invention.
While the invention will be described in conjunction with
an example embodiment, it will be understood that it is not
intended to limit the invention to such embodiment. On the
contrary, it is intended to cover all alternatives, modifications
and equivalents as may be included within the spirit and scope of
the invention as defined by the appended claims.
DETAILBD DESCRIPTION OF THE lNV~. ~ lON
In the drawings, similar features have been given similar
reference numerals.
Turning to FIGURES 1 and 2, there is illustrated an
apparatus 2 in accordance with the present invention for melting
ice which has collected in the bottom of tubular hydrant body 4
extending below hydrant 6. Apparatus 2 may be trailer mounted or
form the rear part of a truck, in either case so that it is readily
mobile and may be carried to the site for thawing a hydrant 6 as
required.
Apparatus 2 comprises an insulated cabinet 8 having a
plurality of doors 10 which provide ready access to its interior.
As can be seen in FIGURES 2, 3 and 4, within cabinet 8 on flooring
11 are a number of interacting components including a water
reservoir tank 12 which may be readily filled from the exterior
through port 14, a water heater 16, a delivery hose 18 to extend
from within cabinet 8 into hydrant body 4, a suction hose 20
201567~
-- 6 --
similarly to extend from within cabinet 8 into hydrant body 4. A
circulation pump 22 is provided for delivering water from reservoir
12 through heater 16 to hose 18 under pressure. A suction pump 24
is associated with suction hose 20 to withdraw water from hydrant
body 4. An appropriate electrical generator 26 (FIGURE 3) which
may be gas driven, is also provided.
Water reservoir tank 12 is preferably centrally mounted
within cabinet 8, for purposes of stability and may, for example,
be a 1.1 cu.m. (240 gallon) tank. As can be seen in FIGURE 5,
which illustrates the circulating system for delivering water from
tank 12 to delivery hose 18, pump 22 draws water from tank 12,
pressurizes it and passes it through coils 30 which are located in
water heater 16. Water heater burner 28, which may for example be
oil-fired, heats water in coils 30 to a temperature of between for
example 250 C to 325 C (482 F to 617 F). Pump 22 brings downstream
water to a pressure of for example between 520 KPa to 860 KPa (75
psi and 125 psi.). Water is preferably heated to 300 C (570 F) and
pressurized to 690 KPa (100 psi.). The heated, pressurized water
is passed to delivery hose 18 having an appropriate nozzle 32 which
may be remotely opened and at which the heated, pressurized water
is flashed to steam. In operation nozzle 32 is preferably
positioned adjacent to ice which has formed at the bottom of
hydrant body 4. Appropriate controls for temperature (to shut off
the wat~er heater if the temperature of the water being heated
exceeds a predetermined value, e.g. 350 C) and pressure are
provided, including water level sensor 34 and temperature sensor 36
in water tank 12, high pressure cut out means 38, high temperature
201~672
cut off 40, temperature regulator 42, pressure relief vent 44 and
pressure relief valve 46 as illustrated. These sensors and
controls are monitored through control panel 48. Power from
generator 26 is distributed through power panel 47 and control
panel 48 to pump 22 and burner 16, as illustrated.
In FIGURE 5, it can be seen that the water circulation
system for the present invention also provides for recycling of
water, through recycle valve 50, back to reservoir 12, when water
is not being passed through nozzle 32 and when for example, burner
28 is not operating. This feature assists in preventing water in
the system from freezing even in the coldest of weather, for
example when doors 10 may be open. As well, water heater coils 30
and the water lines can be drained as a further feature to prevent
freezing, when the unit is not in use, through tank outlet valve
51a, drain valve 51b and/or pressure vent 44. High pressure surges
(transients) are vented by pressure relief valve 46 to reservoir
12. This valve is activated when pressure, for example, exceeds
860 KPa (125 psi.).
If the temperature of the water becomes excessive, as a
result of heating from burner 28, high temperature cut off means 40
will activate to turn off the burner through control panel 48 as
illustrated. Similarly, the flow of water can be cut off for
example if the pressure of the water becomes too high, through high
pressure cut out means 38. This switch is activated when pressure
for example exceeds 2400 KPa (350 psi.). If the water level in
water tank 12 becomes too low, level sensor 34 will be activated
again through control panel 48, and will cause pump 22 to be turned
201567~
-- 8
off.
Delivery hose 18 and suction hose 20 are preferably
mounted on powered reels 52 (FIGURE 5) and 54 (FIGURE 6)
respectively.
As can be seen in more detail in FIGURE 6, suction hose
20, under action by suction pump 24, which pump is powered by
generator 26, withdraws melt water from the bottom of hydrant body
4 and discharges it through outlet 56.
Removable fuel storage tanks 58 for gas for generator 26
and oil for burner 28, are provided in fuel compartment 60 within
cabinet 8.
A typical lay-out for control panel 48, for the apparatus
described herein, is illustrated in FIGURE 7. That control panel
is situated within cabinet 8, preferably near one of the doors 10
so that it is readily accessible to a worker from the outside, and
carries the switches, water (and fuel) level indicators, water
temperature indicator, switches for the various components and
indicator lights to indicate whether the various components of the
apparatus are operational or not.
As can be seen in FIGURES 3 and 4, care has been taken to
ensure that the components are elevated from the floor within
cabinet 8. This is to minimize difficulties which may otherwise be
caused because of the large amounts of water which may be present
during operation of the apparatus. In addition, supports 60 are
fixed to the floor by welding and the components bolted to the
supports. This approach minimizes the effects of corrosion on the
bolts and ensures easy removal of components. As well, as much as
2015672
g
possible, as can be understood in FIGURES 2, 3 and 4, the various
components are modular, in that they are located within cabinet 8
and interconnected so that they may be readily removed from the
cabinet on an individual basis, to facilitate servicing or
replacement.
Thus it is apparent that there has been provided in
accordance with the invention an apparatus for melting ice in fire
hydrant bodies and the like that fully satisfies the objects, aims
and advantages set forth above. While the invention has been
described in conjunction with a specific embodiment thereof, it is
evident that many alternatives, modifications and variations will
be apparent to those skilled in the art in light of the foregoing
description. Accordingly, it is intended to embrace all such
alternatives, modifications and variations as fall within the
spirit and broad scope of the invention.
