DE19547429C2 - Method and breathing gas controller for determining the remaining time of use of breathing apparatus - Google Patents

Description

The invention relates to a method and a Breathing gas controller to determine the remaining time of use Respiratory protective devices according to 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 gives 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 gas pressure measured 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 gas source residual pressure and the respective time measured 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 for devices with a nominal filling pressure of 300 bar and operating environment temperature limits between -30 ° C and + 60 ° C no longer occur negligible non-linearities of those in the application P 44 19 734.9 described standardization of the gas pressure to the Standard filling temperature as a measure of the actual breathing gas display proportional value and the derived value Calculation of the remaining operating time. These deviations will due to the use of composite bottles for doubling the time of use for currently existing devices more meaningful because the duration of the display of the adulterated Values is significantly extended.

The invention is based, which in the Patent application P 44 19 734.9 disclosed method and to improve the associated breathing gas controller so that even Devices whose bottles have a gas pressure of over 200 bar or can absorb over 300 bar over the entire period of use room and in the environment defined in the European standard EN 137 temperature range in proportion to the actual breathing gas supply tional display value and the calculable remaining operating time can be displayed. The temperature range is between -30 ° C and 60 ° C.

The object is achieved by the features of claim 1.

The pressure law of GAY-LUSSAC was used to standardize the gas pressure value to the bottle filling temperature of + 20 ° C in the solution in patent application P 44 19 734.9:

and the relationship derived from it:

This linearization of the proportionality between pressure and However, volume does not take into account the influence of the gas compressibility, 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 is K an exact calculation of the actual breathing gas supply corresponding display value over the to be considered Temperature and pressure range possible.

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

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

These factors represent the product standardized to a reference pressure and a reference volume at a reference temperature

P × V = F (P; T) (3)

with P and T as parameters.

The formula defined in patent application P 44 19 734.9 for calculating the remaining operating time

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

The change necessary to improve linearization is to expand

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

Fig. 1 is a block diagram of a section of the breathing 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

Q * ₀ 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

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 show two block diagrams of the respiratory gas controller and containing the different Realisie approximately possibilities for determining 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 F ₀ 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 fall back on factors, the factors F (P _i ; T _i ) being available via line 6 b to the sensor signal processor 6 for further use according to relationship ( 8 ).

Another solution according to FIG. 1 (claim 5) uses a table memory 15 to provide the conversion factors F ₀ and F (P; T), to which the sensor signal processor 6 accesses after the determination of 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

a (P) = K ₁ + K ₂ × e ^{K3 × pK6} + K ₄ × e ^K5 × p ^K7 (11)

b (P) = C ₁ + C ₂ × e ^{C3 × pC6} + C ₄ × e ^{C5 × pC7} (12)

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

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 F ₀ 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 . This calculates the conversion factors F ₀ and F (P _xM ; T _xM ) according to the relationship ( 13 ) and transfers them via line 6 b to the sensor signal processor 6 , which uses them to convert the standardized conversion factors Q * ₀ ; Q * _X forms and calculates the residual time t _R according to relationship ( 8 ).

Reference list

6

Sensor signal processor

6

aOutput

6

bEntrance

6

address line

6

eAdress line

8th

Program memory

15

Table storage

16

Arithmetic unit
K cascompressibility
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 tables e.g. B. / 1 /
F _N

Conversion factor for standard conditions
F (P _xM

; T _xM

) Conversion factor for pressure and temperature measurement at time t = x
F ₀

Conversion factor for starting gas pressure at time t = 0
C _{1 ... 7}

Constants
K _{1 ... 7}

Constants
General gas pressure
P _R

Residual gas source pressure (declared in accordance with usage instructions for handling gas cylinders)
P _xM

current pressure reading
P _0M

Start pressure measurement at time t = 0
P _0M

× Q * ₀

Starting gas pressure value standardized
Q * ₀

Conversion factor
General gas temperature
P _xM

current pressure reading
t _R

Remaining operational time value
t _x

current time value
V _FL

Gas bottle volume
V _{xN /%}

Breathing gas supply in%
V _xN

actual supply of breathing gas
V _xN

actual supply of breathing gas 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, Volume 1, 3rd ed. (1967) pp. 840 .... 860

(2) F. X. EDER, Modern Methods in Physics, Part 2 (1956), p. 209, p. 257

DIN EN 137 (May 1993), container devices with compressed air DK 614.894.72. 620.1: 62-777, page 4 (European standard)

Claims (6)

1. A method for determining the remaining operating time of respiratory protection devices, in which the gas pressure and the gas temperature of the respiratory 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 are supplied by this delivered gas pressure values 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 × 0 * ₀ , which is also normalized to 20 ° C while taking the gas compressibility K into account, is stored in the program memory and a timer running during the operation and giving the time value t _x is started with the first breath of the device, 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 ), which controls 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 performing the method according to claim 1, characterized in that the sensor signal processor ( 6 ) is assigned a table memory (15). 3. breathing gas controller for performing the method according to claim 1, characterized in that the sensor - signal processor ( 6 ) is assigned an arithmetic unit ( 16 ). 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 for the transmission of the conversion factor F (P _i ; T _i ) of the table memory (15) is connected to the sensor signal processor ( 6 ) via an output line ( 6 b). 5. breathing 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 pressure measurement value P _xM belonging to factor a and a second address line ( 6 e) for selection of the factor b belonging to the pressure measurement value P _{xM 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 after Relationship ( 13 ) calculated conversion factors FD ₀ and F (PxM; T _xM ) is connected to the sensor signal processor ( 6 ).