Note: Descriptions are shown in the official language in which they were submitted.
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~ MOBILE TYPE MEDICAL REFUSE INCINERATING VEHICLE
Backqround of the Invention
The present invention relates to a mobile type medical
- refuse incinerating vehicle.
Some medical refuse discarded from medical facilities such
as hospitals or the like is contaminated with several kinds of
disease-causing germs such as viruses or the like, and possibly
causes secondary infection which should be therefore prevented
by suitably disposing the medical refuse. It goes without
saying that the incineration of such medical refuse is a simple
safe countermeasure.
Conventionally, most of such medical refuse is collected,
for example, by refuse collecting vehicles which make the rounds
of hospitals, and is then accumulated in a predetermined space
where the medical refuse is charged into an incinerator for
burning it.
However, the medical refuse includes various kinds of
matters such as syringe barrels made of plastic, polyvinyl
chloride or the like, syringe needles, dripping chemical
bottles, tubes, incombustible cotton, and the like which are
made of various kinds of materials. In particular, burning of
polyvinyl chloride is very difficult since it emits, during
combustion, a great deal of noxious gas which is the main
culprit behind pollution.
Further, since certain kinds of medical refuse have a
substance which is of a high burning calory or, conversely, a
low burning calory, if the various kinds of medical refuse were
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~ burnt together in a mixed condition, an incinerator would be
overheated and be damaged, or the incomplete combustion would
emit a large amount of unburnt gases.
Explanation will be made of this problem with reference to
graphs A and B shown in Fig. 5.
In such a case that a certain kind of medical refuse is
charged in an incinerator in order to incinerate it at a rate of
30 kg/hour or 5 kg in every 10 minutes, the temperature of burnt
gas in the incinerator reaches about 1,200 deg. C within 3 to 5
minutes as shown by graph A, and accordingly, the incinerator is
overheated.
Further, as shown by graph B, the quantity of gas generated
by the combustion amounts to about 30 m3 after about 4 minutes,
and accordingly, the incineration of the medical refuse is not
complete even though an after-burning furnace is provided. In
this case, a great deal of gas would be emitted.
As mentioned above, conventional burn-up methods have
offered disadvantages such that an incinerator would be
overheated and damaged, and it is difficult to sufficiently cope
with abrupt changes in quantity of generated gas since changes
in the completeness of combustion of the refuse is variable, and
so forth.
Summary of the Invention
The present invention is to provide a mobile type medical
refuse incinerating vehicle adapted to go mainly to medical
facilities such as hospitals, health centers or the like so as
to collect medical refuse which is discarded therefrom and which
is suspected to cause primary or secondary infection, and to
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burn up the collected medical refuse in an incinerator mounted
on the vehicle after it is charged into the incinerator.
According to the present invention, an incinerator for
medical refuse is mounted on a vehicle. The incinerator
comprises a main burning furnace and an after-burning furnace
communicating with each other. A main burner in which oil or
water is injected interchangeably is provided in the main
furnace. In this arrangement, an oil feed type rotary burner
may be used as the above-mentioned main burner, having a three-
way valve for selectively changing over the injection of air,
oil and water. -
Further, a drive cabin is provided on the above-mentioned
carrier vehicle, and accordingly, the carrier vehicle can self-
travel under the control of the driver.
Thus, since the ihcinerator is mounted on the medical
refuse carrier vehicle, medical refuse which has been collected
by the vehicle making the rounds of the medical facilities such
as hospitals or the like, can be readily charged and burnt up in
the incinerator, and accordingly, it is possible to reduce the
steps of disposal thereof so as to remarkably decrease the risk
of secondary infection while enhancing the working efficiency.
Further, lime water is used as the water to be injected
from the above-mentioned main burner. Hydrogen chloride
generated by the combustion of medical refuse is turned into
calcium chloride by injecting this lime water into the main
burning furnace and thus, it is possible to prevent emission of
noxious gas. In this case, the lime water may be obtained by
mixing hydrated lime or calcium hydroxide in water.
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In this incinerator, ignition flame and secondary air are
injected into the after-burning furnace from an after-burner,
and accordingly, the ignition flame and the secondary air are
forced to make contact with unburnt gas led from the main
burning furnace so that the unburnt gas is perfectly burnt up,
thereby it is possible to control the volume of generated gas at
a constant value.
The after-burning furnace is connected thereto with a flue
which is, in turn, connected to an exhaust pipe having an upper
portion opened to the atmosphere. An ejector extending from an
exhaust fan disposed below the exhaust pipe is inserted into the
exhaust pipe in order to smoothly discharge the gas.
Further, various kinds of collected medical refuse are
charged at a constant flow rate into the main burning furnace
mounted on the carrier vehicle while oil is injected in a
sprayed condition from the main burner in order to burn up the
medical refuse.
If the temperature of the inside of the main burning
furnace abruptly increases due to a thermal variation phenomenon
caused by a high burning calory inherent in a particular medical
refuse to be burnt, water is, for a while, injected in a sprayed
condition from the main burner so as to regulate the temperature
of the inside of the furnace in order to maintain a set
temperature.
On the contrary, if the combustion temperature is low,
because the refuse burning calory is low, oil is injected from
the main burner. Accordingly, the combustion temperature of the
main burning furnace is increased so that the temperature of the
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furnace is controlled in a set temperature range in order to
maintain the volume of generated gas at a constant value. Since
the operation of the main burner is temperature varying,
thermocouples are arranged in the main burning furnace and the
after-burning furnace in order to measure temperatures in the
furnaces, respectively.
With this arrangement, it is possible to prevent the
incinerator from being overheated, and to efficiently burn up
medical refuse always at a constant combustion temperature with
a constant volume of combustion gas while preventing occurrence
of pollution.
Preferably, the incinerator incorporates an after-burning
furnace, unburnt gas generated in the main burning furnace is
completely burnt by ignition flame and secondary air from the
after-burner, and the unburnt gas is substantially non-polluting
by the time it is emitted into the atmosphere.
Further, a hearth carriage having on its upper surface a
hearth is provided in the bottom section of the above-mentioned
main burning furnace, which is adapted to travel on rails laid
on the bottom section of the cargo bed so as to be pulled out of
the main burning furnace, and accordingly, the disposal of
incinerated ash can be facilitated.
Brief Description of the Drawinqs
Fig. 1 is a schematic sectional view illustrating an
incinerator on a refuse carrier vehicle according to the present
inventlon;
Fig. 2 is a plan view illustrating the incinerator shown in
Fig. l;
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Fig. 3 is a front view illustrating the incinerator shown
in Fig. 1;
Fig. 4 is a right side view illustrating the incinerator
shown in Fig. 1;
Fig. 5 is a characteristic graph showing a comparison
between the prior art and the present invention; and
Fig. 6 is a principal explanatory view illustrating a
three-way valve in a main burner. f
Description of the Preferred Embodiments
A medical refuse incinerating vehicle 1 comprises a drive
cabin 33 in the front section thereof, and accordingly, can
self-travel under the control of the driver. The vehicle 1
includes in its rear section a rear cargo bed 2 on which an
incinerator 3 is mounted. The incinerator 3 incorporates a main
burning furnace 4, an after-burning furnace 5 and a
flue 6. The after-burning furnace 5 is located above the main
burning furnace 4, and the flue 6 is connected to the after-
burning furnace 5.
The main burning furnace 4 is disposed in the lower section
of the incinerator 3, and a main burner 7 is attached to the
outer surface of one side wall of the main burning furnace 4.
An injection nozzle 8 in the main burner 7 is disposed in an
injection through-hole 10 formed in the wall member 9 of the
main burning furnace 4. Further, this main burner 7 is an oil
feed type rotary burner having a three-way valve 11 for
selectively injecting air, oil and water (refer to Fig. 6).
An oil tank 12 is disposed above the above-mentioned
incinerator 3, and accordingly, with the use of the oil head
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thereof, the fuel oil is fed into an oil feed port 13 of the
above-mentioned three-way valve 11 in the main burner 7.
Adjacent to the oil tank 12, a water tank 14 is arranged.
Since the water tank 14 is arranged above the incinerator 3,
water can be fed into a water feed port 15 in the three-way
valve 11 in the main burner 7 with the use of the water head of
the water tank 14. Air enters the three-way valve 11 through an
air inlet 37. The air is sucked into the main burner 7 due to a
pressure gradient between the outside and inside of the main
burning furnace. Furthermore, as is well known in the art, the
main burner 7 can take in air from the other port (not shown)
such as an air inlet provided at the rear of the main burner 7
and dispense the air in combination with the oil or water.
The above-mentioned three-way valve 11 is adapted to be
changed over under remote manual control, but can be changed
over automatically by an automatic control system added theretoO
A refuse charge port 16 is formed in the rear side wall of
the main burning furnace 4, and is adapted to be opened and
closed by double doors 16A. Instead of using the double
doors, a vertical slidable door can be used for opening and
closing the charge port 16.
An ash take-out port 17 is formed below the charge port 16,
which communicates with the main burning furnace 4, and is
adapted to be opened and closed by double doors 17A.
A hearth carriage 18 having, on its upper surface, a
hearth is disposed in the bottom section of the main burning
furnace 4. The hearth carriage 18 can travel on rails 34 laid
on the bottom section of the cargo bed 2. Accordingly, after
the completion of incineration, the ash take-out port 17 is
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opened so as to enable the hearth carriage 18 to be pulled out
from the main burning furnace 4.
Further, a draw port 19 is formed in the boundary wall
between the main burning furnace 4 and the after-burning
furnace 5 thereabove so that the main burning furnace 4 and
the after-burning furnace 5 are communicated with each other
through the draw port 19.
An after-burner 20 is attached to the outer surface of
the rear wall member 21 of the after-burning furnace 5. This
after-burner 20 is disposed in an injection through-hole 22
formed in the wall member 21. Oil is injected from the after-
burner 20.
Further, adjacent to the after-burner 20, an air-blowing
nozzle 23 is arranged, which is connected thereto with a
blowing fan 24. Further, ignition flame generated from burning
oil, and secondary air fed from the air-blowing nozzle 23 are
forced to make contact with unburnt gas led from the main
burning furnace 4 through the draw port 19. This contact
causes perfect combustion of the unburnt gas.
Thus, if the burning calory inherent to the medical
refuse which is burnt in the main burning furnace 4 is low so
as to cause occurrence of incomplete combustion which results
in generation of unburnt gas, the after-burner 7 is used to
completely burn up the unburnt gas in the after-burning
furnace 5. Accordingly, the volume of exhaust gas is
controlled before emitting the same into the atmosphere.
An exhaust pipe 25 having its upper part opened to the
atmosphere is connected to the above-mentioned flue 6, being
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communicated therewith. An ejector 27 which extends from an
exhaust fan 26 disposed below the exhaust pipe 25 is inserted
into the exhaust pipe 25. This exhaust pipe 25 allows the
burnt gas to be smoothly discharged from the furnace.
Thermocouples 28, 29 are disposed in the main burning
furnace 4 and the after-burning furnace 5, respectively, so as
to measure the temperatures of the insides of the main burning
furnace 4 and the after-burning furnace 5.
A generator 30 and a fuel tank 31 for storing fuel to be
fed into an engine for the carrier vehicle 1 are arranged
underneath the floor of the rear cargo bed 2.
Further, a control board section 32 on which several
control panels are laid is provided in the front section of the
rear cargo bed 2.
The above-mentioned water tank 14 is filled merely therein
with water. However, calcium hydroxide is sometimes charged
therein so as to prepare lime water (a solution of calcium
hydroxide, Ca(OH)z). This lime water is injected into the main
burning furnace 4 from the main burner 7. This injection
causes hydrogen chloride generated by the combustion of the
medical refuse to be turned into calcium chloride, and
accordingly, it is possible to prevent noxious gas from being
discharged into the atmosphere. The formula of this chemical
reaction is given as follows:
Ca(OH)2 ~ 2HCl ~ CaCl2 ~ 2H20
Although it has been explained in the above-mentioned
embodiment that oil and water are selectively injected from the
main burner 7 by changing over the three-way valve 11, the
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main burner 7 may be, of course, used exclusively for the oil
while an additional injection nozzle (which is not shown) for
exclusively injecting the water is provided. It is essential to
selectively inject the oil and the water into the main burning
-; furnace 4.
Explanation will be hereinbelow made of the operation of
the above-mentioned embodiment.
In a preferred situation, collected refuse is burnt at a
rate of, for example, 30 kg/hour, that is, 5 kg for every 10
minutes, the incinerator 3 is operated under a condition in
which the incinerator 3 is prevented from being overheated, and
the volume of generated gas is restrained within a predetermined
range.
~ When the medical refuse is charged into the incinerator 3,
the temperature of the main burning furnace 4 increases so as to
produce burnt gas. Should the burning calory of the medical
refuse be high, the incinerator would be overheated if the
combustion is continued further.
Accordingly, it is necessary to monitor and control
the combustion so as to prevent the main burning furnace 4
from being overheated, by measuring the temperature of the main
burning furnace 4 with the use of the above-mentioned
thermocouple 28, and changing over the three-way valve 11 for
the main burner 7 so as to stop the injection of the oil or to
inject the water in a sprayed condition, instead of the oil.
Through these steps, the temperature of the main burning
furnace 4 can be maintained to be constant, as shown by a
graph C in Fig. 5. At this time, the volume of burnt gas
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caused by the combustion in the after-burning furnace 5 is
controlled so as to be constant as shown by a graph D.
On the contrary, if the burning calory is low due to a
high incombustibility inherent to medical refuse, the
combustion becomes insufficient. In this case, the three-way
valve 11 for the main burner 7 is changed over so as to inject
oil in order to promote the combustion, and accordingly, the
temperature of the main burning furnace 4 is adjusted to a
high value. At this time, the volume of burnt gas is held to
be constant, as shown by the graph D.
