GAS DILUTION SYSTEM

Abstract

A gas dilution system with at least two gas flow control elements. Each of the at least two gas flow control elements features an integrated measuring orifice, designed as a top piece in the form of a valve and connected to a gas container. The gas dilution system extracts gas with a required flow rate via the at least two gas flow control elements from the respectively connected gas container, mixes the extracted gasses at a required dilution ratio into a diluted gas mixture and to makes the diluted gas mixture available at the outlet.

Claims

1. Gas dilution system with at least two gas flow control elements, whereas each of the at least two gas flow control elements features each an integrated measuring orifice, designed as top piece in form of a valve and connected with a gas container, whereas the gas dilution system is designed for respectively removing gas with a required flow rate via the at least two gas flow control elements from the respectively connected gas container, to mix the extracted gasses into a diluted gas mixture at a required dilution ratio and to make available the diluted gas mixture at the outlet.

2. Gas dilution system according to claim 1, whereas the required dilution ratio of the diluted gas mixture is adjustable via the integrated measuring orifices of the at least two gas flow control elements.

3. Gas dilution system according to claim 2, whereas the required dilution ratio of the diluted gas mixture is adjustable via the orifice diameter of the integrated measuring orifices of the at least two gas flow control elements.

4. Gas dilution system according to claim 1, whereas the integrated measuring orifices are respectively designed as an integrated measuring orifice for critical flows.

5. Gas dilution system according to claim 1, whereas the at least two gas flow control elements each continue to comprise an integrated gas pressure regulator.

6. Gas dilution system according to claim 1, whereas the at least two gas flow control elements form a joint structural entity with the respectively connected gas container.

7. Gas dilution system according to claim 1, furthermore featuring an excess flow regulator, in particular a needle valve and/or a back pressure regulator.

8. Gas dilution system according to claim 1, furthermore feature a gas integration, especially as cross fitting of gas pipelines, which are connected with at least two gas flow control elements.

9. Gas dilution system according to claim 8, whereas an initial connection of cross fitting is connected with an initial number of the at least two gas flow control elements, a second connection of cross fitting is connected with a second number of the at least two gas flow control elements, a third connection of cross fitting is connected with outlet.

10. Gas dilution system according to claim 9, whereas a fourth connection of cross fitting is connected with excess flow regulator.

11. Gas dilution method, whereas at least two gas flow control elements are used, whereas each of the at least two gas flow control elements each feature an integrated measuring orifice, designed as top piece in the form of a valve and connected with a gas container, whereas via the at least two gas flow control elements gas is respectively extracted from the respectively connected gas container at a required flow rate, whereas the extracted gasses are mixed at a required dilution ratio into a diluted gas mixture.

12. Method according to claim 11, whereas the required dilution ratio of the diluted gas mixture is adjusted via the integrated measuring orifices of the at least two gas flow control elements.

13. Method according to claim 12, whereas the required dilution ratio of the diluted gas mixture is adjusted via the orifice diameter of the integrated measuring orifices of the at least two gas flow control elements.

14. Method according to claim 11, whereas one respective critical gas flow is generated via the integrated measuring orifices of the at least two gas flow control elements.

15. Application of at least two gas flow control elements for a gas dilution system for preparing a diluted gas mixture at a required gas ratio, whereas each of the at least two gas flow control elements respectively feature an integrated measuring orifice and is designed as top piece in the form of a valve, so that it can be connected with a gas container.

Description

DESCRIPTION OF FIGURES

[0033] FIG. 1 schematically shows a gas dilution system according to the state-of-the-art.

[0034] FIG. 2 schematically shows a preferred designed of a gas dilution system according to the invention.

[0035] FIG. 3 schematically shows another preferred design of a gas dilution system according to the invention.

[0036] FIG. 4 schematically shows a chronology of a flow rate and a pressure, which can be part of a preferred design of a gas dilution system according to the invention.

EMBODIMENTS OF THE INVENTION

[0037] FIG. 1 schematically shows a gas dilution system according to the state-of-the-art; labeled 100.

[0038] This traditional gas dilution system 100 comprises an initial gas pressure container 101 and a second gas pressure container 102. The first gas pressure container 101 contains for example a compensation gas, e.g. nitrogen. The second pressure gas container 102 contains a calibration gas, e.g. a mixture of 5 ppm CO.sub.2 in nitrogen.

[0039] For the initial and the second gas pressure container 101 and/or 102, a pressure regulator 111 and/or 112 is respectively available. A dilution unit 120 is intended hr mixing a certain quantity of compensation gas from the first container 101 with a certain quantity of calibration gas from the second container 102, resulting in a diluted gas mixture.

[0040] This dilution unit 120 comprises several valves 121 and measuring orifices 122. According to this example, six respective valves 121 and six measuring orifices 122 are intended for being able to generate the diluted gas mixture in a desired dilution ratio.

[0041] A regulator 130 is intended for maintaining a required flow rate of the diluted gas mixture and for releasing diluted gas mixture quantities that are not required.

[0042] The generated gas mixture is made available at an outlet 140. A gas analysis device 150 is for example connected to outlet 140. The generated diluted gas mixture can for example be used for calibrating the gas analysis-measuring device 150.

[0043] Such a traditional gas dilution system 100 has many disadvantages. The utilization of several valves 121 and measuring orifices 122 renders the gas dilution system 100 very bulky and requires a lot of space while operation and production are expensive. Furthermore, such a traditional gas dilution system 100 requires complicated handling due to the many structural parts.

[0044] These disadvantages can be removed via a preferred design of a gas dilution system according to the invention, schematically shown in FIG. 2 under label 200.

[0045] The gas dilution system 200 in this example comprises an initial gas flow control element 211 and a second gas flow control element 212. Each of the gas flow control elements 211 and 212 respectively comprises an integrated gas pressure regulator and an integrated measuring orifice that can for example be created as an integrated flow rate regulator.

[0046] The gas flow control elements 211 and 212 are in particular each connected firmly with a gas container and/or pressure gas container 201 and 202.

[0047] An initial gas container 201 and the initial gas flow control element 211 and a second gas container 202 and the second gas flow control element 212 respectively form a joint structural entity. The gas flow control elements 211 and 212 are each expediently designed as top pieces in the manner of a valve.

[0048] An initial gas container 201 can for example contain a compensation gas such as nitrogen, a second gas container 202 might contain a calibration gas, e.g. a mixture of 4 ppm CO.sub.2 in nitrogen.

[0049] The first gas pressure container 201 can for example contain a compensation gas, e.g. nitrogen. The second pressure gas container 202 contains a calibration gas, e.g. a mixture of 5 ppm CO.sub.2 in nitrogen.

[0050] A gas integration 220 is connected with the gas flow control elements 211 and 212 and intended for merging the gasses extracted from gas containers 201 and 202, mixing them to become a diluted gas mixture.

[0051] Via the gas flow elements 211 and 212, gas can be extracted from the respective gas containers 201 and/or 202. By adjusting the diameters of the measuring orifices, the flow rate of the gasses extracted from the respective gas containers 201 and/or 202 can be adjusted. Adjusting these flow rates can serve to control the dilution ratio of the generated diluted gas mixture.

[0052] The integrated measuring orifices of the gas flow control elements 211 and 212 are in particular each designed as measuring orifices for critical flows in order to respectively create a critical flow via the gas flow control element 211 and/or 212. The flow rates of these critical flows are in particular respectively dependent on the temperature and the upstream pressure and/or the density of the respective measuring orifice. The can therefore expediently adjusted and controlled upstream in an easy and uncomplicated manner via the respective gas pressure regulator of the respective measuring orifice.

[0053] In this example, the gas integration 220 is designed as cross fitting. An initial connection 221 of cross fitting 220 is connected to an initial gas flow control element 211 and a second connection 222 of cross fitting 220 is connected with the second gas flow control element 212.

[0054] A third connection 223 of cross fitting 220 is connected to outlet 240 of the gas dilution system 200, at which the generated gas mixture is made available. Analogous to FIG. 1, it is for example possible to connect to outlet 250 a gas analysis-measuring device, which is calibrated via the generated diluted gas mixture.

[0055] A fourth connection 224 of cross fitting 220 is connected to an excess flow regulator 230. The excess flow regulator 230 in this example is designed as needle valve or back pressure regulator and is in particular intended for maintaining a required flow rate of diluted gas mixture and for releasing diluted gas mixture quantities that are not required.

[0056] FIG. 3 schematically shows a further preferred design of a gas dilution system 200 according to the invention. Identical referential labels in FIGS. 2 and 3 designate identical or structurally identical elements.

[0057] Contrary to the gas dilution system 200 according to FIG. 2, gas dilution system 200 has a third gas flow control element 213 and a third gas container 203, which jointly also form a joint structural entity. Gas flow control element 213 is, analogously to gas flow control elements 211 and 212, designed as bottle valve with integrated gas pressure regulator and integrated measuring orifice. A mixture of 5 ppm CO in nitrogen is for example contained as additional calibration gas in a third gas container 203. The second connection 222 of cross fitting 220 is, in this example, connected, both, to the second gas flow control element 212 and the third gas flow control element 213.

[0058] In order to be able to best control the gasses extracted from the gas containers, the exactitude of the flow rate through the respective gas flow control element at a given pressure is in particular known. To this end, flow rate quantity curves against time and/or pressure against time of the respective gas flow control elements are in particular known.

[0059] FIG. 4 schematically shows a respective diagram, whereas curve 410 describes the chronology of the flow and/or flow rate Q as unit [ml/min] and curve 420 describes the chronology of the unit pressure [bar]. Until moment t, flow rate Q can be kept stable and/or mainly stable.

[0060] The following provides an exemplary description how the concentration and/or the dilution ratio of outlet 240 of gas dilution system 200 acc. to the diluted gas mixture of FIG. 2 can be calculated.

[0061] X.sub.outlet designates the concentration and/or dilution ratio of the diluted gas mixture in the ppb range made available at outlet 240. x.sub.inlet designates the concentration and/or dilution ratio of the calibration gas of the second gas container 202.

[0062] Q.sub.pure designates the flow rate of the compensation gas throughout, which is extracted via the initial gas flow control element 211. Q.sub.cal designates the flow rate of the calibration gas extracted via the second gas flow control element 212.

[0063] Concentration x.sub.outlet can be in particular calculated as follows;

[00001]$x_{\mathrm{outlet}}=x_{\mathrm{inlet}}.Math.\frac{Q_{\mathrm{cal}}}{Q_{\mathrm{cal}}+Q_{\mathrm{pure}}}$

[0064] A measurement uncertainty and/or inaccuracy u (x.sub.outlet) of this concentration dependent on the measurement uncertainty u (x.sub.inlet) of the calibration gas concentration of measurement uncertainty u (Q.sub.cal) of the flow rate of the calibration gas and of measurement uncertainty u (Q.sub.pure) of the compensation gas can in particular be calculated as follows:

[00002]${u\left(x_{\mathrm{outlet}}\right)}^2={\left(\frac{Q_{\mathrm{cal}}}{Q_{\mathrm{cal}}+Q_{\mathrm{pure}}}.Math.u\left(x_{\mathrm{inlet}}\right)\right)}^2++.Math.{\left(\left(\frac{x_{\mathrm{inlet}}}{Q_{\mathrm{cal}}+Q_{\mathrm{pure}}}-\frac{Q_{\mathrm{cal}}.Math.x_{\mathrm{inlet}}}{{\left(Q_{\mathrm{cal}}+Q_{\mathrm{pure}}\right)}^2}\right).Math.u\left(Q_{\mathrm{cal}}\right)\right)}^2+.Math..Math..Math.+{\left(\frac{Q_{\mathrm{cal}}.Math.x_{\mathrm{inlet}}}{{\left(Q_{\mathrm{cal}}+Q_{\mathrm{pure}}\right)}^2}.Math.u\left(Q_{\mathrm{pure}}\right)\right)}^2$

LIST OF REFERENCE SIGNS

[0065] 100 Gas dilution system acc. to the state-of-the-art [0066] 101 Initial pressure container [0067] 102 Second pressure container [0068] 111 Initial pressure regulator [0069] 112 Second pressure regulator [0070] 120 Dilution entity [0071] 121 Valves [0072] 122 Measuring orifices [0073] 130 Needle valve [0074] 140 Outlet [0075] 150 Gas analysis measuring device [0076] 200 Gas dilution system [0077] 200 Gas dilution system [0078] 201 Initial pressure container [0079] 202 Second pressure container [0080] 203 Third pressure container [0081] 211 Initial pressure regulator, bottle valve [0082] 212 Second pressure regulator, bottle valve [0083] 213 Third pressure regulator, bottle valve [0084] 220 Gas integration, cross fitting [0085] 221 Initial connection of cross fitting [0086] 222 Second connection of cross fitting [0087] 223 Third connection of cross fitting [0088] 224 Third connection of cross fitting [0089] 230 Excess flow regulator (e.g. needle valve or back pressure regulator) [0090] 240 Outlet [0091] 250 Gas analysis measuring device [0092] 410 Chronology of flow rate Q [0093] 420 Chronology of pressure