DE19547429A1 - Residual available use time for breathing and diving equipment - Google Patents

Abstract

The breathing gas pressure values are used to find the remaining usable life time (TR). They are calculated from gas pressure (P), gas temperature (T) compressibility (K) depending on gas type and the initial breathing gas pressure (POM x Qo*) standardized to 20 degrees C. A timer started at the first inspiration gives time factor (tx) during the period of use. Gas temperature and pressure values are fed to the sensor signal processor (6) which derives a calculated standardized conversion factor (Qx*) to give the residual use time based on residual gas pressure and actual time. The sensor has an associated table storage (15) or arithmetic unit, and if used, the storage uses address lines (6d) and (6e) to transmit pressure and temperature values to the sensor and line (6b) to transmit storage (1t) conversion factor to sensor.

Description

The invention relates to a method and a Breathing gas controller to determine the remaining time of use Respirators and diving equipment after patent application P 44 19 734.9.

With this invention, the device wearer is continuously informed about the current breathing gas supply and the resulting remaining operating time. For this purpose, the standardized starting pressure is stored in the program memory, a timer which runs during the operating time and outputs the time value is started and then the respective current gas pressure measured value is continuously fed to the sensor signal processor. In this processor, the measured gas pressure value is converted into the normalized gas pressure value P _{x (+ 20 ° C)} , taking into account the measured current gas temperature, and is determined and displayed, taking into account the specified residual gas source pressure and the respective time measurement value, as the remaining use time value t _R.

The breathing gas controller implementing the method is included a sensor signal processor equipped in indirect Connection with the breathing gas source and in direct connection with a program memory and a display element.

With this solution it is possible to increase the breathing gas supply and the Remaining operating time of devices up to 200 bar in one limited temperature range to determine relatively accurately.  

Even with devices with 300 bar nominal filling pressure and Ambient temperature limits between -30 ° C and + 60 ° C non-negligible nonlinearities of the in the application P 44 19 734.9 described standardization of the Gas pressure to the standard filling temperature as a measure for one actual breathing gas supply proportional display value and the calculation of the remaining operating time derived from this. These deviations are due to the use of Composite bottles help to double the usage time currently existing devices even more significant because the duration of the display of the falsified values considerably is extended.

The invention was based on the object in Patent application P 44 19 734.9 disclosed method and to improve the associated breathing gas controller so that too for devices whose bottles have a gas pressure of over 200 bar or can take up over 300 bar, over the entire Period of use and in the defined in the European standard EN 137 Ambient temperature range the actual Breathing gas supply proportional display value and the resulting value predictable remaining operating time can be displayed.

For normalizing the gas pressure value to the bottle filling temperature rature of + 20 ° C served in the solution in the patent application P 44 19 734.9 the printing law of GAY-LUSSAC:

and the relationship derived from it:

This linearization of the proportionality between pressure and But volume does not take into account the influence of the Gas compressibility K the for those to be considered here Pressure and temperature ranges for calculating the exact Remaining time is necessary.

In addition, only when considering gas compressibility K an exact calculation of the actual Respiratory gas supply corresponding display value over the to considering temperature and pressure range possible.

To take the gas compressibility K into account Numerical values in the range of values of gas pressure and Gas temperature for the gas used to be known. The known relationships for the calculation of K only apply for limited value ranges / 2 /.

For the linearization of the breathing gas supply display, the Literature / 1 / extracted, experimentally determined Conversion factors used.

These factors set that to a reference pressure and Reference volume at a reference temperature standardized product

P × V = F (P; T) (3)

with P and T as parameters.

The formula defined in patent application P 44 19 734.9 to calculate the remaining time of use

contains the linearization formula defined in relation (2) for the quantities P _{x (+ 20 ° C)} contained in formula (4):

The necessary to improve the linearization Change is the expansion of

to the relationship

where F _{N is} the conversion factor at standard pressure P _N = 1 bar and standard temperature T _N = 293 K.

Q (T) in relation (5) replaced by Q * (P; P _N ; T; T _N ) results in:

The object has been achieved according to the invention in that the respiratory gas pressure values used to determine the residual use value t _R are calculated taking into account the gas pressure P, the gas temperature T and the gas type-dependent compressibility K by the start breathing gas pressure P, which is also normalized taking the gas compressibility K into account _0M × Q₀ * is stored in the program memory and, with the first breath of the device wearer, a timer which is running during the operating time and which gives the time value t _x and is not shown is started, after which the respective current gas pressure and gas temperature values are continuously fed to the sensor signal processor, controlled by the latter, a conversion factor F (P _xM ; T _xM ) is determined and a standardized conversion factor Q _x * is calculated from this and taking into account the previously determined residual gas pressure P _R and the respective current time value t _x according to the relationship

is determined as the remaining use time value t _R , with the sensor signal processor of the respiratory gas controller used to carry out the method optionally having a table memory or an arithmetic unit assigned to it and the table memory via a first address line for transmitting the pressure measurement value P _xM and a second address line for the transmission of the temperature measurement _value T _{xM is} connected to the sensor signal processor and for the transmission of the conversion factor F the table memory is connected to the sensor signal processor via an output line or the first address line for the selection of the factor belonging to the pressure measurement value P _xM a and the second address line for the selection of the factor b belonging to the measured pressure value is connected to the sensor signal processor and an output line from the table memory to the sensor signal processor leads to the transmission of factors a and b or that the arithmetic unit has a entrance sleitung for the transmission of the pressure measurement values P _xM and the temperature measurement _values T _xM and an output line for the transmission of the factors a and b calculated from the pressure measurement value P _xM and the temperature measurement _value T _{xM is} connected to the sensor signal processor.

The invention is to be explained on the basis of exemplary embodiments will. The drawing shows in

Fig. 1 is a block diagram of a section of the respiratory gas controller with table memory,

Fig. 2 is a block diagram of a section of the breathing gas controller with arithmetic unit.

The inventive method is using the breathing gas controller described in P 44 19 734.9 with those shown in Fig. 1 and Fig. 2 additions to determine the normalized conversion factors

Q₀ * and Q _x *.

The measured values P _xM and T _xM prepared by the sensor signal processor 16 are used with the conversion factors stored or calculated in the additions shown in the sensor signal processor 16 in accordance with the relationship ( 8 ) to determine the remaining operating time t _R.

The display of the actual breathing gas supply V _xN in liters under standard conditions (1 bar; + 20 ° C) can be calculated when:

V _xN = P _xM × Q _x * × V _FL (9)

take place, where V _{FL represents} the gas bottle volume in liters.

It is also possible to display the respiratory gas supply V _{xN /%} in percent of the starting volume:

. Fig. 1 and 2 represent two block diagrams of the respiratory gas controller and containing the different implementation possibilities for the determination of the conversion factors F (P; T) and their transmission to the sensor signal processor:

The solution according to FIG. 1, claim 4. uses a table memory 15 to provide the conversion factors F₀ and F (P; T). This table memory 15 contains tables, e.g. B. from / 1 / taken conversion factors F (P _i ; T _i ) which only for discrete measured values P _i ; T _i apply. The sensor signal processor 6 can only be used for the rastered measured values P _i ; T _{i use} factors and use the factors F (P _i ; T _i ) via line 6 b to the sensor signal processor 6 for further use according to relationship (8).

A further solution according to FIG. 1 (claim 5) uses a table memory 15 to provide the conversion factors F₀ and F (P; T), which the sensor signal processor 6 accesses after determining the pressure measurement value P _xM . The table memory 15 contains factors a (P), b (P) associated with each pressure measurement value P _xM, which factors _{previously exist} in an external computer according to the relationships

with any resolution, e.g. B. have been calculated with the resolution 1 bar. These factors are read out for each pressure measurement P _xM by the sensor signal processor 6 via line 6 b and the factor b (P) according to the relationship

(P _rel corresponds to P _N ; V _rel corresponds to vol. At 0 ° C)
multiplied by the measured temperature _value T _xM in the sensor signal processor 6 and used to calculate the relationship (8).

. The solution according to Figure 2 is used to calculate the conversion factors F₀ and F (P, T) an arithmetic unit 16, which may also be an arithmetic processor.

The sensor signal processor 6 transmits the processed measured values P _xM via the line 6 a; T _xM to the arithmetic unit 16, it calculates the conversion factors F₀ and F (P _{x M;} T _{x M)} according to the equation (13) and transfers them via the line 6 b the sensor signal processor 6, the resulting normalized conversion factors Q₀ * ; Q _x * forms and calculates the residual time t _R according to relationship (8).

Reference list

6 sensor signal processor
6 a exit
6 b entrance
6 d address line
6 e address line
8 program memories
15 table memory
16 arithmetic unit
K gas compressibility
a (P) function of gas pressure
b (P) function of gas pressure
F (P; T) conversion factor
F (P _i ; T _i ) conversion factor from works of tables e.g. B. / 1 /
F _N conversion factor under standard conditions
F (P _xM ; T _xM ) conversion factor for pressure and temperature measurement at time t = x
F₀ conversion factor for starting gas pressure value at time t = 0
C _{1. . . 7} constants
K _{1. . . 7} constants
P General gas pressure
P _R residual gas source pressure (declared in accordance with usage instructions for handling gas cylinders)
P _xM current pressure measurement
P _0M start _{pressure measured} value at time t = 0
P _0M × Q₀ * Start breathing gas pressure value normalized
Q₀ * conversion factor
T gas temperature in general
P _xM current pressure measurement
t _R remaining time of use
t _x current time value
V _FL gas bottle volume
V _xN actual breathing gas supply in liters under standard conditions
V _{xN /%} breathing gas supply under standard conditions as a percentage of the starting breathing gas supply

bibliography

[1] D′ANS · LAX, paperback for chemists and physicists, vol. 1, 3rd ed. (1967) p. 840. . . 860
[2] FX EDER. Modern methods of physics. Part 2 (1956), p. 209 ,. P. 257.

Claims (6)

1. A method for determining the remaining operating time of breathing apparatus and diving equipment, in which the gas pressure and the gas temperature of the breathing gas source are measured during operation, are fed via an amplifier and an analog-digital converter to the sensor signal processor equipped with a memory, and the gas pressure values supplied by this for determining the remaining operating time are used according to patent application P 44 19 734.9, characterized in that the respiratory gas pressure values used to determine the remaining operating time value t _R are calculated taking into account the gas pressure P., the gas temperature T and the gas type-dependent compressibility K by the starting breathing gas pressure value P _0M × Q₀ *, which is also standardized to 20 ° C, taking into account the gas compressibility K, is stored in the program memory and, with the first breath of the device wearer, a timer which runs during the operating time and gives the time value t _{x is} started _After which the respective current gas pressure and gas temperature _values P _xM and T _{xM are} continuously _fed to the sensor signal processor ( 6 ), a conversion factor F (P _i ; T _i ) or F (P _xM ; T _xM ) is determined and from this a standardized conversion factor Q _x * is calculated and taking into account the previously determined residual gas pressure P _R and the respective current time value t _x according to the relationship the remaining use time value t _{R is} determined. 2. Breathing gas controller for determining the remaining time of use of breathing apparatus and diving equipment, comprising breathing gas sources, pressure sensor, temperature sensor amplifier, analog-digital converter, sensor signal processor, memory, display element and alarm device according to patent application P 44 19 734.9. characterized in that a table memory ( 15 ) is assigned to the sensor signal processor ( 6 ). 3. Breathing gas controller for determining the remaining time of use of breathing apparatus and diving equipment, including breathing gas source, pressure sensor, temperature sensor. Amplifier. Analog-digital converter, sensor signal processor. Memory, display element and alarm device according to patent application P 44 19 734.9, characterized in that an arithmetic unit ( 16 ) is assigned to the sensor signal processor ( 6 ). 4. breathing gas controller according to claim 2, characterized in that the table memory ( 15 ) via a first address line ( 6 d) for the transmission of the pressure measurement value P _xM and a second address line ( 6 e) for the transmission of the temperature measurement _value T _xM with the sensor Signal processor ( 6 ) is connected and to transmit the conversion factor F (P _i ; T _i ) the table memory ( 15 ) is connected to the sensor signal processor ( 6 ) via an output line ( 6 b). 5. Respiratory gas controller according to claim 2, characterized in that the table memory ( 15 ) via a first address line ( 6 d) for the selection of the factor a belonging to the pressure measurement value P _xM and a second address line ( 6 e) for the selection of the pressure measurement value P _xM belonging factor b is connected to the sensor signal processor ( 6 ) and an output line ( 6 b) from the table memory ( 15 ) to the sensor signal processor ( 6 ) transmits the factors a and b. 6. respiratory gas controller according to claim 3, characterized in that the arithmetic unit ( 16 ) via an input line ( 6 a) for transmitting the pressure measured values P _xM and the temperature _{measured values} T _xM and an output line ( 6 b) for transmitting the according to the relationship ( 13 ) calculated conversion factors F₀ and F (P _xM ; T _xM ) is connected to the sensor signal processor ( 6 ).