Device for calibrating gas electrodes

A device for calibrating gas electrodes inserted into a gas testing container within sterile environment of an operation room is mounted on a movable frame and has one side to be sterilized and carrying a work table with the gas testing container and another side at which a nonsterile person operates. A gas supply unit is mounted on another side of the frame. Those two sides are separated from each other by a yoke which supports gas hoses extended between the gas testing container and the gas supply unit.

BACKGROUND OF THE INVENTION 
The invention relates to a device for calibrating gas electrodes. 
The measuring of gas partial pressures in organic tissue find increasing 
use in medicine, because physiological conditions of the total organism, 
as well as the logic organism can be defined with great assurance, so 
that, in particular during surgery better supervisions are made possible. 
The electrodes of gas analysers used for measuring gas pressures are very 
sensitive in their function, so that it is very often required to restore 
the electrodes immediately before use. However, this must take place in 
the sterile environment of the operation room, because the electrode is 
applied to the patient after preparation. 
SUMMARY OF THE INVENTION 
In order to provide the possibility to calibrate gas electrodes within the 
sterile environment of the operation room, the invention provides that a 
sterilisable calibration chassis is provided, which is connectable to a 
supply unit by means of hose lines through rapid clutches, as well as a 
moveable frame which receives the supply unit, whereby the frame is 
provided with a work table with a yoke for receiving the calibrating 
chassis which can be covered with cloths. 
The advantage of the device consists in that the device is provided for 
calibrating electrodes in the sterile environment of the operation room. 
Thereby, the calibration chassis with the hoses and the rapid clutches are 
sterilized, while the moveable frame remains unsterilized; it is covered, 
however with sterile cloths. The flow of bacteria from sterile cloths is, 
as is known, so low, so that the increase of the bacteria amount does not 
exceed the required value. 
The connection of the calibrating chassis is performed in that a sterile 
person places the calibraing chassis onto the table of the movable frame 
which table is covered with sterile cloths, and throws the sterile hoses 
over the yoke of the table to a person on the nonsterile side. This person 
then performs the connecting of the clutches. 
In order to substantially facilitate the handling of the calibrating 
chassis and to prevent the flow of bacteria through the gas lines one or a 
plurality of throttle valves are provided on a calibrating container which 
is mounted on the calibrating chassis, whereby thermostatized liquid flows 
through rapid clutches and hoses into the calibrating container and into 
which calibrating gas can be fed from beneath through a gas line by means 
of a water volume standing above a batch, the outputs of the throttle 
valves being coupled with the gas line of the calibrating container and 
the inputs being coupleable with the gas supply containers through 
bacteria filters, hoses and the rapid clutches. 
The advantage of this device consists in that in the calibrating container, 
into which the prepared electrodes are placed, an atmosphere of moisture 
saturated calibration gas is present, which is a prerequisite for an exact 
calibration, that the additional bacterisation of the working area is 
prevented by filters, and that the gas flow of calibration gas can be 
easily adjustable from the sterile side. 
In order to further improve the handling from the unsterile side, the 
moveable frame is provided with means for mounting gas supply containers, 
a thermostat and a connecting plate on which the nonsterile connections of 
the rapid clutch are mounted. 
Due to this arrangement, the manipulation of the connecting of the lines is 
facilitated and can be performed with one hand, so that any repercussion 
on the sterile side, displacement or soiling of the sterile cloths, site 
or position changes of the moveable frame or the supply units, are 
eliminated. 
The novel features which are considered as characteristic for the invention 
are set forth in particular in the appended claims. The invention itself, 
however, both as to its construction and its method of operation, together 
with additional objects and advantages thereof, will be best understood 
from the following description of specific embodiments when read in 
connection with the accompanying drawing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1, on a frame 1 rollers 100 are provided, as well as a table 101 
with a yoke 102, a connecting plate 103 with (consecutively disposed) 
rapid couplings or clutches (clutch 105 is covered), a retaining device 
106 for gas supply container 107, 108 (container 108 is covered) and a 
mounting face 109 of frame 1 for a thermostat 110. The frame is covered 
with a sterile cloth 111 in such a manner that a calibrating chassis 2 
shown as a block can be mounted on table 101 which is covered with the 
cloth. The yoke 102 which is disposed under cloth 111 provides a support 
for gas and water hoses 201,202,203,204 which are thrown over the yoke 102 
in a sterile condition and are coupled with the nonsterile supply units 
like gas bottles and thermostats in an nonsterile manner. Thereby, an 
arrangement is provided which may be nonsterile below cloth 111 and behind 
yoke 102, but is sterile before the yoke and on the working table. When 
the calibrating chassis 2 is sterilized, the device can be used in the 
operating area. 
A calibrating container 2201 is mounted on a base plate 200 in FIG. 2. It 
consists of a jacket container 2010 through which thermostatized liquid 
2020 flows and through which a gas line 2011 runs which expands toward a 
testing container 2012. A water volume 2014 for moistening the calibrating 
gas in container 2201 stands above a batch 2013, and an opening 2015 is 
provided into which the electrode to be calibrated is inserted and from 
which the testing gas 2016 escapes. The feeding of the gas is carried out 
through line 2017 from supply line armatures 300,400. The armatures 300, 
400 are the same, so that it suffices to describes armature 300. 
The supply of gas is carried out through a line hose 201 from one of the 
gas supply containers which are mounted on the moveable frame. The gas, 
which at this time is not bacteria free, passes through a bacteria filter 
302, which, as an example, is provided with exchangeable cellulose acetate 
filters. A finely adjustable throttle valve 303 with calibrated adjustment 
knob 304 permits the control of the flow quantity in line 320. Line 320 
and line 420 of the second armature 400 are fed to the gas line 2017 and 
back to the calibrating chassis through a suitable T-piece, not shown. 
The total device is constructed of materials which permit a sterilisation 
with hot steam. 
For calibration, at first a gas flow is adjusted with adjustment knob 304, 
so that the gas 321 slowly bubbles through the water volume 2014. After 
reaching stability, a measuring point is determined by the electrode 
inserted (here not shown) into the opening 2015, and then a second 
measuring point is determined in the same manner with the adjustment knob 
of armature 400 and gas 421. A prerequisite for using the method is the 
use of two calibrated gases in the supply containers, as well as the 
knowledge of the calibration curve of the electrodes, so that two 
calibration points are sufficient for determining the whole scale. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of 
devices for calibrating gas electrodes differing from the types described 
above. 
While the invention has been illustrated and described as embodied in a 
device for calibrating gas electrodes, it is not intended to be limited to 
the details shown, since various modifications and structural changes may 
be made without departing in any way from the spirit of the present 
invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention.