EP0673676A1 - Système de mélange des gaz - Google Patents

Système de mélange des gaz Download PDF

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Publication number
EP0673676A1
EP0673676A1 EP95104134A EP95104134A EP0673676A1 EP 0673676 A1 EP0673676 A1 EP 0673676A1 EP 95104134 A EP95104134 A EP 95104134A EP 95104134 A EP95104134 A EP 95104134A EP 0673676 A1 EP0673676 A1 EP 0673676A1
Authority
EP
European Patent Office
Prior art keywords
gas
flow
flow line
control means
line
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95104134A
Other languages
German (de)
English (en)
Inventor
Larry Felix Knight
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Praxair Technology Inc
Original Assignee
Praxair Technology Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Praxair Technology Inc filed Critical Praxair Technology Inc
Publication of EP0673676A1 publication Critical patent/EP0673676A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/06—Mixing phases by adding a very small quantity of one of the phases or microdosing
    • B01F23/061—Adding a small quantity or concentration of an additional phase in a main phase, e.g. acting as a carrier phase
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/10—Mixing gases with gases
    • B01F23/19—Mixing systems, i.e. flow charts or diagrams; Arrangements, e.g. comprising controlling means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/21—Measuring
    • B01F35/211—Measuring of the operational parameters
    • B01F35/2113—Pressure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/20—Measuring; Control or regulation
    • B01F35/22—Control or regulation
    • B01F35/221—Control or regulation of operational parameters, e.g. level of material in the mixer, temperature or pressure
    • B01F35/2213—Pressure

Definitions

  • the invention relates to a gas blending system. More particularly it relates to a system for the accurate mixing of a tracer gas with a carrier gas.
  • An important industrial service carried out in a variety of applications is a leak detection service for the detecting of leaks in pipelines or other fluid passage or storage systems.
  • Such service typically utilizes a mass spectrometer or other devices to sample the atmosphere surrounding a point in a system suspected of containing a leak.
  • Helium which is commonly used for such purposes, is used because it is rare in the atmosphere and rapidly dissipates into the atmosphere.
  • a leak in one area does not contribute to a high leak reading in other areas, as can occur when other tracer gases, such as fluorocarbons or sulfur hexafluorides are employed.
  • helium is expensive to use in its pure form so an inert carrier gas, typically nitrogen, is mixed with the helium and then injected into the system to be checked. While the proportions in which the helium will be mixed with nitrogen can vary, a typical helium/nitrogen mixture will commonly be in the 1-2% range, although higher or lower proportions of helium can also be employed.
  • an inert carrier gas typically nitrogen
  • the flowrate of the carrier gas e.g. nitrogen
  • the flowrate of the carrier gas can easily be changed.
  • a second approach suggested in the art was to provide a "manual" control system to achieve a steady state gas mixture. If the carrier gas flow rate changes, the system is adjusted to change the tracer gas flow rate. Such a system would require the use of two flow regulators and two back pressure regulators in conjunction with control valves to provide steady state conditions during the desired gas blending operation.
  • the invention employs a back pressure regulator on the tracer gas line, with the control signal therefor coming from the carrier gas line.
  • the tracer gas pressure will match the carrier gas pressure.
  • the objects of the invention are accomplished by a low-cost gas blending system, as herein described and claimed, that is less complex and more reliable than the "automatic" control system referred to above. It provides all the advantages thereof without the cost and complexities of the flow meters, control valves and microprocessor based control utilized in said "automatic" control system.
  • the gas blended system of the invention is intended for portable use in leak detection industrial service activities carried out at job sites in the field. For such purposes, it offers the added advantages of increased reliability, decreased maintenance and no source of power requirement.
  • the gas blending system of the invention has the reliability of the "manual" system, it is a simpler, less complex system than said prior art system, and is a full automatic system. Thus, while it is simpler than the manual system, it provides automatic adjustment of tracer gas flow in response to varying carrier gas flow and/or downstream pressure.
  • the essence of the invention is the use of a back pressure regulator on the tracer, i.e. helium, gas line, with the signal therefore coming from the carrier, i.e. nitrogen, gas line.
  • said back pressure controlling regulator represented by the numeral 1
  • Tracer gas line 2 is piped for flow into the common discharge manifold 4 from which blended gas is removed in line 5.
  • Carrier gas line 6 containing fixed orifice 7 is also piped for flow into said manifold 4.
  • Back pressure controlling regulator 1 is controlled by signal 8 from pressure sensor 8A capable of sending a control signal corresponding to the pressure m the flow line of said carrier gas upstream of the positioning of flow control means, e.g. fixed orifice 7, in the flow line for said second gas.
  • said back pressure controlling regulator 1 in tracer gas line 2 senses the carrier gas pressure in line 6 upstream of carrier gas orifice 7.
  • valve 3 in tracer gas line 2 and of orifice 1 in carrier gas line 6 determine the proportion of carrier gas and tracer gas in the resulting blended mixture.
  • Control valve 3 is adjustable so as to enable the proportion of tracer gas to carrier gas to be adjusted to any desired proportion of the gases for any particular gas blending operation. However, once set, the proportions of said gases will remain the same as flow and pressure conditions change over the course of a given gas blending operation.
  • orifice 7 in carrier gas line 6 can be replaced by a variable orifice, i.e. control valve. If control valve 3 in tracer line 2 is employed, however, then the use of a variable orifice in carrier gas line 6 offers no real advantage. If control valve 3 is changed to a fixed orifice in other embodiments of the invention, then the use of a variable orifice, i.e. control valve, in carrier gas line 6 in place of fixed orifice 7, would enable the tracer gas/carrier gas mixture ratio to be adjusted for different application needs.
  • variable orifice 7 in line 6
  • flow control valve 3 in line 2
  • the carrier gas is usually employed at higher flow rates than pertain to said tracer gas level, hence, would require a larger and more expensive variable orifice to be used in line 6 than would be the case for the preferred practice, as illustrated in the drawing, of using a variable orifice in tracer gas flow line 2.
  • valve 3 can be replaced by a fixed orifice so that both lines 2 and 6 contain fixed orifices.
  • the use of such embodiments would reduce the cost of the gas blending system, but would eliminate the adjustability feature of the mixture proportions unless, in conjunction therewith, fixed orifice 7 in line 6 were changed to a variable orifice as referred to above.
  • the use of valves in both lines 2 and 6 is also within the scope of the invention, but is not necessary for the reasons above.
  • the invention provides a low cost, reliable means for accurately mixing a tracer gas with a carrier gas or carrying out other desirable gas blending operations.
  • the system of the invention provides a reliable system that, due to its less complex nature than previous alternatives, is well suited for portable use in providing accurately mixing of a tracer gas in a carrier gas for use of commercially important leak detection operations.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Accessories For Mixers (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Measuring Volume Flow (AREA)
EP95104134A 1994-03-22 1995-03-21 Système de mélange des gaz Withdrawn EP0673676A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US21600094A 1994-03-22 1994-03-22
US216000 1994-03-22

Publications (1)

Publication Number Publication Date
EP0673676A1 true EP0673676A1 (fr) 1995-09-27

Family

ID=22805261

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95104134A Withdrawn EP0673676A1 (fr) 1994-03-22 1995-03-21 Système de mélange des gaz

Country Status (3)

Country Link
EP (1) EP0673676A1 (fr)
BR (1) BR9501145A (fr)
CA (1) CA2145160A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108607466A (zh) * 2018-05-16 2018-10-02 山西太钢不锈钢股份有限公司 一种判断混料机加水喷头脱落或堵塞的方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117027774B (zh) * 2023-08-10 2024-04-09 捷贝通石油技术集团股份有限公司 一种自适应压力调节的气体示踪剂注入方法及装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB191027703A (en) * 1909-12-01 1911-06-15 Cfcmug Improved Regulating Device for Mixing Fluids in given Proportions and for Measuring the same.
GB743655A (en) * 1952-11-17 1956-01-18 Blackman Keith Ltd Installation for mixing aeriform media
US3221757A (en) * 1963-03-29 1965-12-07 Jr Robert P Newton Method and apparatus for mixing gases
GB2202459A (en) * 1987-03-23 1988-09-28 Distillers Company The Gas mixing apparatus
EP0578578A1 (fr) * 1992-07-10 1994-01-12 Selas Corporation Of America Procédé et dispositif pour mélanger des gaz
DE4225981A1 (de) * 1992-08-06 1994-02-10 Linde Ag Verfahren zur Herstellung eines Gasgemisches

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB191027703A (en) * 1909-12-01 1911-06-15 Cfcmug Improved Regulating Device for Mixing Fluids in given Proportions and for Measuring the same.
GB743655A (en) * 1952-11-17 1956-01-18 Blackman Keith Ltd Installation for mixing aeriform media
US3221757A (en) * 1963-03-29 1965-12-07 Jr Robert P Newton Method and apparatus for mixing gases
GB2202459A (en) * 1987-03-23 1988-09-28 Distillers Company The Gas mixing apparatus
EP0578578A1 (fr) * 1992-07-10 1994-01-12 Selas Corporation Of America Procédé et dispositif pour mélanger des gaz
DE4225981A1 (de) * 1992-08-06 1994-02-10 Linde Ag Verfahren zur Herstellung eines Gasgemisches

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108607466A (zh) * 2018-05-16 2018-10-02 山西太钢不锈钢股份有限公司 一种判断混料机加水喷头脱落或堵塞的方法

Also Published As

Publication number Publication date
CA2145160A1 (fr) 1995-09-23
BR9501145A (pt) 1995-10-24

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