DD152981B1 - PROCESS FOR THE PRODUCTION OF GAS MIXTURES - Google Patents

Description

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wherein the flow rates of the individual gases are displayed by means of a preferred float meter in the flow path between the throttle valves and the outflow regulator, individually immediately behind the respective throttle valve and / or together immediately after flowing through the common mixture space by means of a flow rate indicator having a plurality of scales, at the start of work or After interruption of work, the sequence begins in the setting of the individual gas quantities with the largest single gas quantity and ends with the smallest single quantity. A shortcoming of this gas mixing method is that the process is relatively complicated and that as a result the cost of manufacturing, calibration and testing such gas mixing equipment is still relatively high. In addition, the difference between P _{1 n} and τ _z t _{that is} present due to the _{dependencies according to} the invention between the respective individual gas pressure P _{1 n} , the common pressure p ₂ and the maximum flow pressure Рз _{твх is} relatively large, so that an increased residual quantity of individual gases in the supply used Gas bottles remain and can not be used.

It is an object of the invention to increase the effectiveness of the production of gas mixtures, in particular for inert gas welding.

The essence of the invention

The invention has for its object to develop an improved process for the preparation of gas mixtures and provide measures that ensure a high uniformity of the mixed gas composition and amount simplifying the process flow and allow high usability of the gas resources to be used.

According to the invention this object is achieved in that while maintaining the individual pieces P ₁ "immediately measured the flow rates of the individual gases and then the individual pieces Pi" to a common pressure all individual gases p _{2 are} relaxed, at the same time the flow rates of the individual gases are metered, and that below the individual gases are combined without significant loss of pressure and also forwarded without significant pressure loss against the consumer pressure p ₃ , wherein the individual gas pressures Pi "are set so that the ratio of P _{1 n} to the maximum consumer pressure _{рз тах} equal to the absolute value of the maximum critical pressure the individual gases, so that:

^p 1 η > ,

^P 3 max ^{crit nax}

The essential advantage of the method according to the invention is that gas mixtures can be produced from any number of single-phase gases with easily realizable measures and conditions, without the need for special control measures and the requisite control devices as well as adjustment and testing expenditures. Furthermore, it is an advantage of the invention that the gas resources, in particular the compressed gas cylinders, can be utilized to a greater extent.

Ausführungsbeispiei

The invention will be explained in more detail below using an exemplary embodiment. In the accompanying drawing, the circuit diagram of a gas mixer for carrying out the method according to the invention is shown. Oer gas mixer 1 has three input stages 2,3 and 4 and an output nozzle 5. At the inlet nozzle 2 is not shown supply line for argon, at the inlet 3 a supply line not shown for carbon dioxide and at the inlet 4 a supply line also not shown connected for oxygen. All these gases are at the same pressure of ρ; = 3.2 bar (absolute pressure) supplied by conventional and not shown gas cylinders via corresponding pressure reducer. In the flow direction subsequent to the inlet nozzle 2,3 and 4, a float meter 6, a return flow 7 and a throttle valve 8 are connected within the gas mixer 1 respectively. The three outgoing lines 9, which lead out of the respective throttle valves 8, open directly into the common mixing chamber 10, which in turn is connected directly to the outlet port 5. In their course of flow, the three gases from the inlet ports 2,3 and 4 pass directly into the corresponding float meter 6, where the flow rates of the individual class can be read and then through the respective Rückströmsicherungen 7 and throttle valves 8, wherein the individual gases with the throttle valves 8 dosed and to a pressure common to all individual gases p _{2 are} relaxed, the size of the set total flow of all individual gases and the flow resistance (consumer pressure) of the downstream consumer (eg welding machine) results, so that 5 reaches the common mixing space 10 with the direct connection of the outlet nozzle is that the pressure p ₂ in the common mixture space is substantially equal to the respective consumer pressure

 According to the method according to the invention, the following printing conditions apply to the exemplary embodiment:

Argon: p _crit = 2,06bar (absolute pressure) of CO _2: Pcrit = 1,84bar (absolute pressure) O _2: Pcrit = 1.89 bar (absolute pressure) This is / Pkritmex / = 2.06

The maximum consumer pressure of a welding torch unit to be used in the present case is p ₃ ma = 1.5 bar (absolute pressure) with a maximum mixed gas consumption of 301 / h. Therefore, the pressure P _{1 n was set} at 3.2 bar (absolute pressure). With this pressure setting for p, "a condition of the inventive method is ensured so that once set flow rates of the individual gases and the mixing ratio during welding even with any variation of the mixed gas below 30 l / h or even with any change in the consumer pressure of the welding torch below 1 , 5 bar are kept constant.

Claims (1)

Process for the preparation of gas mixtures of two or more components, preferably for inert gas welding, while supplying the individual gases with adjustable, but mutually different, but during the gas sampling invariable individual pieces of gas P ₁ " to the gas mixture at defined pressure conditions with respect to the flow back pressure in the consumer line (Consumer pressure) and gas relaxation in throttle valves, in particular to achieve high efficiency in the gas mixture, characterized in that while maintaining the individual gas pressures Pi "measured immediately the flow rate of the individual gases and then the individual gas pi" relaxed to a common pressure p ₂ all individual gases , wherein at the same time the flow rates of the individual gases are metered, and that subsequently combined the individual gases without significant pressure loss and also without significant pressure loss against the Verbraucherdru ck рз be forwarded, the individual gas pressures Pi _n are set so that the ratio of Pi "to the maximum consumer pressure Рзтах equal to or greater than the absolute value of the maximum critical pressure of the individual gases, so that: For this 1 page drawing Field of application of the invention The invention relates to a process for the preparation of gas mixtures of two or more components, preferably for inert gas welding using defined pressure conditions between the individual pressures and the flow back pressure in the consumer line, in particular for achieving a high effectiveness of the gas mixture. Characteristic of the known technical solutions For the production of gas mixtures, a method is known in which the individual gases of a mixture with an adjustable, but mutually different, but during the gas removal constant pressure P _{1 n are} supplied within the gas mixer by separate throttle valves, which each have a known per se Rückströmsicherung is preferably upstream of a common pressure common to all individual gases p ₂ and fed to a common mixture space, after which the mixed gas by an adjusted membrane-controlled outflow, which holds the pressure prevailing in the common mixture space pressure p _2, regardless of the mixed gas quantity and composition, is conducted such that the mixed gas flows without substantial loss of pressure in the delimited by the membrane high-pressure chamber, said high-pressure chamber preferably represents even the common mixture space and that the mixed gas in its further course unthrottled up to and through the regulator opening into the also limited by the membrane low pressure space of Abströmreglers and thereby relaxes to a pressure p ₃ , which represents the back pressure of the downstream load, the ratio p ₂ to the maximum flow back pressure p ₃ max in the consumer line is greater than the absolute value of the maximum critical pressure of the individual gases, so that the following applies: