Note: Descriptions are shown in the official language in which they were submitted.
,h(~ (sc~-,t i~ (J~.ion rcl.,'~s to a method il~d -~,parf~t~s
for use i.n l~e de(ont,rilinating oi ho.s~ital and li~e (~ui.pi.,ent.
~ y.~C~It variety o-f equil;mcnt in metal, ch;na~7are, 2nd
plastics is uscd in hospi-tals and for medical care in gcneral,
and ;s lral)sfel~red daily from paLient to pat;ent, wh.ich Ineans
th~t t]~e ~ t::icles must be carc:E~Il]y cleaned hetween each occasion
of u~;e l~hell-tlle eq~lipmerlt has been rouglll.y c]ealled and washed
l:he ~lecon~ .ination ha.s of-l-ell been performed hy flushing the
art:i.cles wi-th ]lot wate.r, usually at about 90C for several rninutes,
wllich is considered sufficient -to relllove mos-t bacteria. ITot--~ater
flushing takes a ]ot of tillle and wastes much energy. The
treatment furtherrnore heats up the a~ticles so that it is
necessary -to permit them to cool-o~f, or have them flushed with
col.d water, so the staff can handle them. The wastage in time
and hot water is a noticeable cost, and olle aim of the present
invention is to provide a mcthod and apparatus, which makes
possi.b].e a more rapid and energy-saving handling, which further-
more ensures a better neutraliza-tion of bacteria, than has been
obtainable before.
Accordingly, this invention provides a method of
decontaminating hospital and like equiprnent, comprising arranging
the pieces of equipment, after a conventional cleaning and
washing, into a recep-tac.le such -that they are easily accessible
all around, and subjecting -the same to a short shock of moist
hot-air having a temperature of above 500C hy circulating air,
which has been heated to sai.d tempeLature by an electl-ic heater
having a sufficient capacity to raise during a short n-~oment
of time the ternperature of passing air -to above about 500C,
at a veloci-ty of about 30-50 m/sec., by a fan havi!lg a cal~acity
of about five exchanyes per sc~cold of air within sa;.d ~-eceptacle,
throuyh a c].oscd circulation conduitry~
Ins~ead of the hot-water fl~lsliing it is now p.L-ov.i.ded
_])rlt t-~)e (`(lUip,il( 11~ I-e.r: a coi~V~ nl-ional wa.shing, is silbje-l,-d
~o a sllc)rl, ,]-~ock-like aetion of hot air. ~y seleetir,g the til~le
alld the terllperature parar,leters in a su;tal~le l-nanner, i-t is pos-
;;]~lc to chtain Ihe ~lesired resul~ w it}lOUt dny tr oub]esorne heat-
;nc, o:E l.he L):i.c~( c~s ol~ (Juil)rnc?nt.
'.[`hc pres( llt- i.nvelltioll al SO provi(les an apL)ar?tus ~r
d(~con l:.-n~:i rla I: i on O r hc,.ipita] arld like c~uipm(erlt without
Ipp-reciably hcdlil-lg ~he o(1uil,tlc-n-1t i-lse:lf after a eonventional
c]ea~ g and washirlg eolrlpr;sill~: a recepta(]e adalpted to hold
Ihe al-tieles easily ac-essible all ac-ouncl, a Ean having a eapaeity
eorresponding to about five exchanges per seeond of air within
said Leeeptaele and means for clriving said fan, an electrie
heater having a suffic;ent capaeity -to raise, during a short
moment of time, the termperatllre o:E passing air to above a~out 500~C,
eondui-ls Eor eonnecting the Fan and the heater to the receptacle
in a elosed eireulation eonduitry, where the supply of air to
said reeeptaele oeeurs at a veloeity of about 30-50 m/see., and
eontrol mealls to activate said heater and said fan so a short,
high-temperature passacle of air is obtained. The eapaeity of
~he fan permits five exchanges
-la-~
of a:ir l,(r sceond ~.iiih;.n Ll-le receptacl.e, and a fast--ac'Lion v.~l-Je
is p:[ovi~ d l~e~ccn the heater and the receptacle. ..eans are
furthcrmore provided to rcglll.ate the heater, tl~e fan and the valve,
so a short, hot-tcmpera-ture air-flow Lh~-ough the receptaele i.s
ol~ inc~d.
. 'rime and l:r.~mp(_rcl-~ul-c .Ire o:E cou.rse deciclil-g facto:rs,
and there c3:1^e c:el--t~l;.n mirl:Lml~rn val.~ies, which m~lst he observed
for obtain;ng an ace~eptaele decontami]lation. An increase of either,
or both factors will ensure results approaching or reaching a
sterile corlclition, whieh may be obtained wi~hout any noticeab]e
~ 10 increase of ~he tcmperature of the pieces of equipment. Tes-ts
have shown -that the hot--a;r ~shock will provide far bet-ter
resul-ts than an e~;tended heat trea-~ment, performed at -temperatllres
commonly used for decontam;.nation purposes.
The fan and the air circulation system is formed so
air will be supplied ~o -the reeep-tacle at a velocity of 30 - 50
m/sec., whieh makes the air enter even small openings.
A eonduit for supplying washing fluid is preferably
eonneeted to the reeeptaele, which tS provided ~ith a drain valve.
Regulating means are provided to prevent the valve in -the air
eireulation conduit being opened until the washing fluid conduit
and the drain valve have been shut off.
The motor driving the fan preferably is of a two-speed
type, guiding means being provided to permit the motor to operate ~.
in the high-speed range only, when the valve in the air
~ cireulation eonduit is open.
: The heater may eontain eleetrie heating elemen-ts, whieh
may be of a "small-package" type havi.ng a high watt densi-ty
. : within a l;mited space, or may be of a more eonventional type.
In the latter case the air eireul.ati.on eonduit pre:Eerably eontaills
a brancll condllit by--passing the receptaele, the valve is of the
tllree-way type and governing means are provided to hold the Lranch
conduit open while -the fan operates in the lower speed ral-ge.
2-
The invention will now be described in more detail by
way of example only, with reference to the accompanyiny drawings
in which:
Figure 1 very schematically shows a plant according to
the invention for the decontamination of hospital equipment, and
Figure 2 shows a more complete plant provided with
means Eor automatic governing of the operation.
With the embodiment according to Figure 1, a receptacle
10 is adapted to receive a wire mesh basket 11 containing the
pieces o~ equipment to be treated, and which have been cleaned
and washed in a conventional manner. A fan 12 and an electric
heater 13 are connected to the receptacle by means of conduits
14 and 15, whereby heated air, in use, may be brought to circu-
late through the receptacle in a closed circuit.
The heater 13, which preferably includes heating ele-
ments having a high watt-density, for instance of the type
marketed under the trade name o~ PORCUPINE, has a suf~icient
capacity to raise the temperature to 350 800C. On most occa-
sions a treatment time of a few seconds i5 sufficient. A temp-
erature of 485C is critical for most bacteria and an operating
temperature at, or above 500C is advantageous.
The heat treatment will be more ef~icient, if the air
caxries some degree o~ moisture. If the pieces of equipment have
been recently washed and are still damp, a rapid evaporation will
oc~ur, which on most occasions is sufficient to ensure the desired
moisture content.
Conduit 15 is however provided with a nozzle 16 for
spraying water into the ~ot, circulating air flow. The amount of
water supplied is governed by means 17 of arbitrary known type.
A thermostat 18 is mounted in conduit 15, and governs
the supply of current to heater 13.
- 3~-
o~
The plant further includes governing means
(not shown) for determining the temperature and the treat-
ment time.
The components may be fitted and arranged to
comply with local requirements, and receptacle 10 may be
formed as a cabinet having a door and shelves, where bigger
articles, such as basins and bed pans~ may be stacked. It
is of course important that all articles are made available
to the hot air a.ll around.
In Figure 2 reference 20 denotes a receptacle
adapted to receive the articles to be treated, and which may
be closed by a lid 21. Depending upon the nature and the size
of the a.rticles a wire mesh basket, to be hung into the re-
ceptacle, may be used, or the receptacle may be provided with
shelves or hooks where the articles may be located.
A heater 22 contains three electric elements 23,
and is connected to recepta.cle 20 by means of a conduit 24.
A second conduit 25 connects the recpetacle with the entrance
of the hea.ter. A fan 26 is fitted in last mentioned conduit
and is driven by an electric motor 27, pre~erably of the
two-speed type. A shut-off valve 29 is provided in conduit 24.
The heating elements 23 may be of the.so called
''small-packagel~type~ having a high wa.tt-density within a
restricted spa.ce, ~or instance of the type marketed under the
trade name PORCUPINE, by means of which it is possible to
obtain a. practically instantaneous high-capacity heat emission.
The fan ma.y be started a. few seconds before the heater, or is
operated in the lower speed range during the wa.shing ir
driven by a two-speed motor, and may then be easily accele-
rated to the higher speed just before the heat treatment starts.
When hea.ting elemen-ts 23 are of a more conventional
type it may be a.dvantageous to provide a branch conduit 28
(indicated by broken lines) between conduits 24 and 25, to
by~pass recepta.cle 20. Valve 29 will then be for~ed as-a
three-way unit. ~y opening the ~alve 29 towards branch conduit
28 it is possible to maintain a circulation in part Or the
.
-
, ,
system, so that part is prepared for the desired temperature
range, and with the fan operated in its lower speed range.
The receptacle is arranged so the articles may
be washed therein. To that end water is supp].ied through a
number of suitably loca.ted noz~les connected to a. supply
pipe 30, in which there is a pump 31 and a controlled valve
32. Due to the nature of the contaminations the washing is
preferably performed by non-heated water. Suitable solvents
and detergents a.re supplied from a container 33 by a pipe 34,
in which there a.re pump 35 and a controlled valve 36.
The recepta.cle is in its lower part provided with
a.controlled dra.in va.lve 37 for washing and flushing water.
A filter 38 is provided in conduit 25 to catch possible drop-
lets carried away by the hot air, preventing them to reach
the ~an.
The fan and the heater should preferably be di-
mensioned to provide at least five exchanges of air per
second in the receptacle, a.t a temperature of between 350 C
and 800 C. Most ba.cteria actually associated with hospital
equipment will be destroyed at ll85oc~ so it will be advanta.-
geous to opera.te a.bout at 7 or above 500 C. Equipment to be
used for operations will require a higher degree of freedom
from bacteria, which ma.y be a.ttained by using the higher tem-
pera.ture range, and/or a longer time ~or the trea.tment - the
time however still being measurable in seconds.
With a..plant of the type shown in Figure 2 the
temperature withinthe hea.ter may be about 800 C, at the inlet
to the recepta.cle the temperature may be 700 C, and within
the recepta.cle a. temperature of 500C will then be maintai.n-
a.ble during the trea.tment period.
- The shocking.of the bacteria., usually ~scherichia
coli and Staphylococcus aureus, is of deciding importance.
Tests have shown,.tha.t an action at 500 - 600C for 2
seconds will provide a.bout the same result upon the bacteria
as a treatment du~ing 1 minute at 200 C.
.
It is definitely desired that the articles should
not be heated themselves, but -that they shall be recover-
a.ble from the receptacle without any cooling-down period.
The short heat shock, to which the articles will be subjected,
will not result in any appreciable heating of the material
in the articles.
The hi~h degree of air exchange means that the
a.ir will pass through the receptacle with a. high velocity,
about 30 - 50 m/sec. This makes the air enter into all
openings and it will a.lso, by passing past pockets, cause a
reduced pressure therein which sucks away possible contaminated
residues of air.
It is known that moist hot air has a higher
capa.city for killing ba.cteria. than dry hot a.ir, and by washing
the articles directly in the receptacle there will be a. suf-
ficient amount of moisture ava.ilable for obtaining the desir-
able results. The high a.ir velocity makes it a.ppropriate to
include the filter 38, which will catch possible droplets
carried a.long with the air, without being immedia.tely vapo-
rized. Such droplets could damage the fan when entering the
same at the high speed used.
The object is to cause a. short hea.t shock, and
the plant is prefera~ly fitted with means for automa.tic
governing.
A control panel 40 is provided with starting and
stopping buttons 41 and 42, respectively, as well as with a
selector 43 for manua.l or-automatic operation. The control
panel is connected to a. monitoring unit 44, which may be
programmed in any suitable, well known manner. There are
further two raws of buttons, one, 45, for selecting a suit-
able temperature range (t) and one, 46, for selecting the
required time (T). Sîgna.l lamps I, II and III are also pro-
vided to indica.te "operating", "finished" and "out of order",
respectively. The la.st mentioned indication co~lld mean that
raquired safety steps have not been taken, that the desired
tempera.ture has ~ot been rea.ched, or the like.
~2~
The temperature downstream of the heater will be
sensed by a thermosta-t 47, issuing signals to control panel l~o.
The va.lYes included in the conduitry are motor
operated~ and in connection to each of them there is a control
means receiving and issuing s:ignals determining and reporting
t.he position of the a.ssociated valve.
Beside the three-way valve 2g at the inlet to
receptacle 20, there is a valve 39 a.t the outlet from the
latter. There is further at lea.st one locking device 48 for
lid 21 and ha.ving an a.ssoica.ted signa.l issuing means.
During the ~ashing, as well as during the hot-air
treatment, the lid will ha.ve to be securely locked, a.nd during
the wa.shing opera.tion va.lves 29 and 39 will be closed. The
operation of pumps 31 and 35, a.s well as of valves 32 and 36
in the wa.ter and detergent conduits9 a~d furthermore of the
drain va.lve 37, will be determined by monitoring unit 44 and
belongs to well known technique.
Electric current to the fan motor 27 as well as
to the heating elements 23 will be supplied through mains 49,
and it is evident tha.t the number of elements which are to
be switched in will be determined by a.ctuation of a button
in row 45. During the washing operation fan 27 is run in its
lower speed rangel and va.lve 29 is positioned to shut-off
the recepta.cle, while permitting a circulation by way of branch
conduit 28 ba.ck to fan 26. The hea.ting system will thus be`
prepared to issue the hea.t shock.
When the washing is finished and the receptacle
~ 20 ha.s been dra.ined, va.lves 32,36 and 37 are closed, where-
:. upon valve 29 is shifted so its closes the bra~ch conduit 28
and opens the pa.ssage to the receptacle. Simultaneously valve
,; 39 is opened, a~d it is importa~-t tha.t last mentioned valves
: ~ are designed to permit a ra.pid operation, for instance being
of the fla.p or butterfly type. While the valves are operated
.the fan motor 27 is automa.ti~a.lly brought into its higher
. speed range~ and air is, a.t a high speed, made to pass from
the hea.ter into the receptacle at the qelected tempera.ture.
;,
.
: 7
,
Thermostat 47 activates the monitoring unit 44, so a suffi-
cient amount of current is supplied to elements 23 to cover
the increased demand caused by receptacle 20 and the return
conduit being switched into the circulation system.
When the heat shoc}c is over, valves 29 and 39
must be closed before lid 21 to the recepta.cle can be opened.
As mentioned before the a.rticles themselves will not be heated
and they can be removed as soon as the hot air trapped in
the receptacle has escaped to the atmosphere.
Further devices for sensing temperature~ pressure
and safety function may be included, when considered advise-
a.ble with respect to the size of the plant.
The components included are schema.tica.lly illust-
ra.ted, and their sha.pe and rela.tive si~e may va.ry in many
ways within the scope of the appended claims. With a small
plant 9 and especially in a. plant where the washing is
performed before the articles a.re brought into the container,
the heat treatment components may be built into a cabinet,
where the control panel forms pa.rt of the front.
The heater and the fan are comparatively expensive
units and it is possible to fit a multi-way valve (not shown)
downstream of the heater by means of which the latter may be
connected/ in turn, to severa.l recepta.cles, which are con-
secutively, loaded, hea.ted and emptied.
.
