Note: Descriptions are shown in the official language in which they were submitted.
1
Disinfection Device and Method for Performing Disinfection Cycles
FIELD
The present disclosure relates to a disinfection device for performing
disinfection cycles of
water from at least one water circuit of an apparatus, in particular a
hypothermia device.
The disclosure further relates to a method for performing disinfection cycles
of water in at
least one water circuit of an apparatus, in particular a hypothermia device,
in a disinfection
circuit of a disinfection device, the water circuit being connected to the
disinfection circuit
into a common circuit and the water being pumped out of the water circuit
through the
disinfection circuit.
BACKGROUND
In order to avoid the risk of infections after operations, for example,
cardiac surgery,
extensive measures which involve considerable technical and organizational
effort are
taken in the operating theaters. In the case of open-heart surgery, for
example, the patient
must be connected to a heart-lung machine, wherein his blood is oxygenated and
decarboxylated in an extracorporeal circuit for the duration of the operation.
The blood
temperature must be regulated at the same time to prevent the patient from
cooling down.
The blood is temperature controlled by means of a heat exchanger, the heat
transfer
medium of which is water, which is correspondingly temperature controlled in a
hypothermia device. Hypothermia devices are known to be mobile, multi-circuit
heating-
cooling devices that are independent of water connections and are mostly used
for the
controlled temperature control of two water circuits during extracorporeal
perfusion for the
controlled temperature control of the patient and the cardioplegia circuit
using heat
exchangers. It is known that in hypothermia devices, the heat transfer liquid
water is
contaminated with germs relatively quickly in practice and a biofilm forms on
the wetted
inner surface of the lines and tanks in the hypothermia device. Germ
contamination and the
formation of biofilms usually occur even when the hypothermia device has been
cleaned in
accordance with the maintenance schedule. If contaminated water
unintentionally escapes
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from a water circuit of the hypothermia device, there is a risk of serious
post-operative
infections of the patient.
A disinfection device and a method of the type mentioned above are known from
DE 10 2017 000 426 Al. The water of the water circuits is passed for
disinfection at least
temporarily through a disinfection apparatus which has an apparatus for
providing a
disinfection fluid. The disinfection fluid is added to the liquid that is
passed through, and
the water is disinfected by the disinfection fluid in a deactivation unit. The
disinfected
liquid is then passed into an elimination unit for eliminating the
disinfection fluid, in which
the disinfected liquid remains or passes through until the disinfection fluid
is completely
removed from the disinfected liquid by the elimination unit. Ozone is
preferably used as a
disinfection fluid. UV radiation is used in the elimination unit to decompose
and break
down the disinfection fluid after the liquid has been disinfected.
.. Furthermore, it is widespread and customary to add oxidizing agents, for
example,
hydrogen peroxide, to the water in hypothermia devices approximately every two
to three
weeks. Handling such means poses certain health risks and is increasingly
discredited for
reasons of employee protection.
SUMMARY
The present disclosure aims to provide a disinfection device and a method
which ensures,
in a technically simple and particularly reliable manner, a sterilization of
the process water
from hypothermia devices without the separate use of disinfectants and
therefore without
the need to eliminate the same. A comfortable and uncomplicated commissioning
should
thereby be possible and frequent water changes in the hypothermia device can
be dispensed
with.
According to the present disclosure a disinfection device is provided that
comprises
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i. at least one disinfection circuit for passing through the water from the
water circuit
having at least one electrolysis cell designed as a flow-through cell for the
in situ
generation of oxidizing agents,
ii. means for connecting the water circuit to the disinfection circuit to
form a common
circuit,
iii. electronics (8) for controlling the disinfection cycles and
iv. means for supplying power to the components of the provided
disinfection circuits.
The present disclosure also provides a method, wherein the water is passed in
the
disinfection circuit through an electrolysis cell designed as a flow-through
cell, in which
oxidizing agents are generated in electrochemical reactions and in situ, and
is pumped several times within a disinfection cycle through the circuit formed
by the water
circuit and the disinfection circuit.
The method and the device according to the present disclosure enable a
disinfection and
sanitization of the water from the water circuits of the hypothermia device
without the
separate addition of disinfectants, since the disinfectants are generated
directly in the
electrolysis cell when the water to be disinfected flows through. The repeated
flow through
the electrolysis cells ensures that the impurities in the water are safely
broken down and
only small amounts of unstable oxidizing radicals remain in the water, which
radicals
remove themselves. The water is therefore disinfected on the basis of in situ
ongoing
electrochemical processes through water electrolysis. This also ensures a
comfortable and
uncomplicated commissioning of the disinfection device, since all that is
required is to
couple the hoses of the water circuits of the hypothermia device to the
disinfection device
and to start the disinfection cycle.
In one embodiment of the disinfection device, this has a pump in each
disinfection circuit
for repeatedly passing the water through the water circuit and the
disinfection circuit within
a disinfection cycle. Depending on the embodiment of the hypothermia device, a
circulation
pump can also be used within the hypothermia device to pump water through the
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disinfection circuit in the disinfection device and the water circuit in the
hyperthermia
device. A separate pump in the disinfection device can be omitted in this
case.
A flow sensor and in particular also a temperature measurement sensor may also
be further
present in each disinfection circuit. In one embodiment, a sensor for
measuring the
electrical conductivity is a further component per disinfection circuit. The
measurement
data of at least one of these sensors are taken into account in the
electronics for controlling
the disinfection cycles.
In one embodiment the electronics control a disinfection cycle taking into
account
measured data, such as the water temperature and the flow rate.
In one embodiment of the disinfection device, empirically determined data from
experiments are taken into account in the electronics for controlling the
disinfection cycles.
In particular, the number of passes of the water through the flow-through cell
required to
generate a sufficient quantity of oxidizing agents for disinfection is
determined in such
experiments. Alternatively, at least one further sensor can be positioned in
each disinfection
circuit, which sensor measures the concentration of oxidizing agent in the
water, so that the
electronic controller processes these measurement data and controls the
disinfection cycle
on the basis of this data.
The flow-through cell preferably has an electrode packet having two edge-side
contact
electrodes, which are supplied with DC voltage, and in one embodiment, at
least one
bipolar electrode which is arranged between the contact electrodes and spaced
therefrom.
The bipolar electrode is in particular a diamond particle electrode which has
doped,
preferably boron-doped, diamond particles which are embedded in one layer and
without
mutual contact with one another in a non-conductive plastic carrier layer and
are exposed
on both sides of said carrier layer. Flow cells of this type are particularly
effective with
regard to the generation of oxidizing agents from the water or its
constituents by means of
electrochemical processes.
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The disinfection device is preferably designed as an additional device for a
hypothermia
device, can be positioned on the hypothermia device and can be connected
thereto.
In the method for performing disinfection cycles, the water is pumped in an
electronically
controlled manner through the water circuit and the disinfection circuit
within a
disinfection cycle until it is safely disinfected. As already mentioned, the
electronics
control a disinfection cycle based on certain data or measured values, such as
the water
temperature and the flow rate.
In an embodiment for the method of the present disclosure, the water to be
disinfected may
be at least largely free of hardeners. In this embodiment, water can be used
in the
hypothermia device which is at least largely free of hardeners, for example,
by suitable
additives or by treatment in an osmosis device.
In an embodiment for the electrochemical processes in the electrolysis cell,
the water to be
disinfected may have an electrical conductivity of at least 1 mS/cm. This
embodiment can
be achieved in a particularly simple manner in that at least one salt, for
example, NaCl,
KC1, K2S0 4, Na2SO4, K2CO3 and/or NA2CO3, is dissolved in the disinfecting
water. Such
salts can be mixed in or added in a simple manner when filling the water into
the
hypothermia device.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features, advantages and embodiments of the present disclosure are now
described
in more detail with reference to the drawing, which illustrates an embodiment.
Shown are
Figure 1 is a schematic structure of a disinfection device,
Figures 2 and 3 are views of an embodiment of an electrolysis cell designed as
a flow-
through cell and
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Figure 4 is a sectional representation along the sectional plane marked line
in Figure
1.
DETAILED DESCRIPTION
Referring to the drawings, Figure 1 schematically shows the structure of an
embodiment of
a disinfection device according to the disclosure as an additional device, in
particular for a
hypothermia device 1. The hypothermia device 1 is a multi-circuit heating-
cooling device
for the controlled temperature control of independent water circuits and can
be any
hypothermia device from the prior art. The hypothermia device indicated in
Figure 1 works,
for example, with two independent water circuits, such as a patient circuit
and a
cardioplegia circuit, and therefore contains two water tanks 2, 2' indicated
in Figure 1. In
order to prevent the process water from becoming contaminated and the
associated
formation of biofilms on the tank walls and the walls of the hose lines
through which the
process water flows, the process water should in particular be disinfected
daily.
The disinfection device according to the disclosure is placed on the
hypothermia device 1
and is preferably fixed using mounting brackets or the like provided therefor.
The
disinfection device therefore has a correspondingly designed housing 3, which
is only
indicated in Figure 1, on the outside of the housing 3 couplings 5 for
connecting to the ends
of the hoses 6, 6' and 7, 7' of the hypothermia device 1 and a display 4
having control
elements and display elements. The display 4 and the couplings 5 are only
indicated in
Figure 1. The couplings 5 are marked or designated accordingly so that the
inlet hoses 6, 6'
and return hoses 7, 7' belonging to the two water circuits of the hypothermia
device 1 on
the disinfection device can be connected to the correct or assigned couplings.
The disinfection device shown in the example according to Figure 1 contains
two
disinfection circuits corresponding to the number of water circuits of the
hypothermia
device 1. The two disinfection circuits each have, in the flow direction of
the water to be
disinfected, a flow sensor Di, D2 for measuring the flow, a temperature
measurement
sensor Ti, T2, a pump Pi, P2 and an electrolysis cell designed as a flow-
through cell 10, 10'
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and connecting hoses 18. In an alternative embodiment, the disinfection device
has a single
disinfection circuit matched to the hypothermia device. Furthermore, instead
of or in
addition to the pump provided in the disinfection circuit, a circulation pump
which may be
present in the hypothermia device can be used.
Flow sensors Li and L2 are optionally provided in the disinfection circuits,
in particular in
front of sensors Di and D2, for measuring the conductivity of the water
flowing through.
The sensors Di, D2, Li, L2, Ti, T2, the pumps Pi, P2 and the two flow-through
cells 10, 10'
are connected to electronics 8 for controlling the disinfection cycles. The
electronics 8 and
the individual components of the disinfection device are supplied with voltage
via a power
supply unit 9.
Figures 2 to 4 illustrate the structure of an embodiment of a flow-through
cell 10, 10'.
Every flow-through cell 10, 10' has a housing 11 made of two housing parts 11
a which are
firmly connected to one another, in particular welded to one another. In the
housing 11 is
located an electrode packet 12 having two edge-side contact electrodes 13, 13'
and a bipolar
electrode 14, in particular a diamond particle electrode, located between the
contact
electrodes 13, 13'. Each frame-like spacer 15 made of electrically insulating
material
separates the two contact electrodes 13, 13' from the bipolar central
electrode 14. All
electrodes 13, 13' and 14 are, in particular, thin, rectangular plates having
essentially
matching dimensions.
The edge-side contact electrodes 13, 13' consist, for example, of platinum-
coated or mixed
oxide-coated titanium, of diamond electrodes produced by means of CVD
technology, or of
another electrochemically stable electrode material. The spacers 15 consist of
a chemically
resistant, electrically non-conductive plastic, for example, PP
(polypropylene), PVDF
(polyvinylidene fluoride) or PTFE (polytetrafluoroethylene). The diamond
particle
electrode 14 is in particular a conventional diamond particle electrode as is
known, for
example, from EP 2 004 880 Bl. This diamond particle electrode consists of
doped
diamond particles, which are embedded in one layer and without mutual contact
with one
another in a non-conductive plastic carrier layer and are exposed on both
sides of said
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carrier layer. The electrical contacting of the contact electrodes 13, 13'
takes place, for
example, on the contact tabs 16 which are formed with the contact electrodes
13, 13' and
which are guided liquid-tight through the housing 11 outwards by means of a
seal or a
sealing material. The housing 11 is further provided with two connections 17
having flow
openings, to which the hoses 18 running inside the disinfection device and
connecting the
individual components to one another are connected.
The means for disinfection of the water are generated in the operation of the
respective
disinfection circuit or in the operation of the flow-through cell 10, 10' in
the flow-through
cell 10, 10' by electrochemical conversion of the water itself or of
introduced water
constituents. In particular, OH radicals are generated at the electrodes,
which radicals
oxidize organic components in the water or react with salts dissolved in the
water and
generate oxidizing agents. Oxidizing agent mixtures which neutralize the
impurities
contained in the water are therefore formed in the in situ operation of the
flow-through cell
10, 10'.
In order to prevent the formation of deposits, for example, lime, in the
components of the
water circuits of the hypothermia device and the disinfection circuits of the
disinfection
device, water may be used that is free or largely free of hardeners such as
calcium or
magnesium in the hypothermia device. Such water is, for example, produced
using a
softening or reverse osmosis system. The water may further have a certain
electrical
conductivity on the order of at least 1 mS/cm, so that the formation of
oxidizing agents is
supported in the flow-through cells 10, 10'. At least one salt, for example,
NaCl, KCl,
K2504, Na2SO4, K2CO3 and/or Na2CO3, is therefore added to the water when it is
filled into
the water tanks 2, 2' of the hypothermia device 1. These salts can be provided
in the form of
powder or tablets. The amount of salt to be added depends on the known water
volume.
Both disinfection circuits can perform a disinfection cycle simultaneously or
in succession
when operating the disinfection device. The electronics 8 that can be operated
via the
display 4 can provide both options as alternatives. In the course of a
disinfection cycle, the
water is conveyed from one of the tanks 2, 2' several times via the pumps Pi.
P2 through the
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water circuits of the hypothermia device and the disinfection circuits of the
disinfection
device and thus passes through the respective flow-through cell 10, 10'. A
common
disinfection process having a water volume of eight liters, for example,
requires about five
minutes. An acoustic or visual signal can indicate the termination of the
disinfection
process. The electronic controller works in particular on the basis of the
results of empirical
experiments and taking into account known and available data, such as that of
the water
temperature and the flow rate. Alternatively or additionally, the electronics
control the
disinfection cycles on the basis of measurement data from at least one sensor
which detects
the concentration of oxidizing agent in the water, for example, the
concentration of free
chlorine, or which measures the redox potential.
In alternative embodiments of the flow-through electrode, said flow-through
electrode has
only two contact electrodes and no bipolar electrode, in a further alternative
embodiment,
two or three bipolar electrodes can be provided in the electrode pack.
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Reference number list
1 .............. hypothermia device
2,2' ........... water tank
3 ............ housing
4 .............. display
5 .............. coupling
6, 6' ......... circulation hose
7, 7' .......... return hose
8 ........ electronics
9 .............. power supply unit
10, 10' ........ flow-through cell
11 ............ housing
1 1 a .......... housing part
12 ....... electrode pack
13, 13' ....... contact electrode
14 ............. bipolar electrode
15 ............. spacers
16 ............. contact tab
17 ....... connection
18 ............. hose
Di, D2 ......... flow sensor
LI, L2 ......... conductivity sensor
PI, P2 ......... pump
Ti, T2 ... temperature measuring sensor
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