Гричин С.В., Ульянова О.В. - Английский язык для инженеров сварочного производства (1044906), страница 12
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One can easily damage a regulator by simply forgetting to wipeclean the cylinder, regulator, or hose connections. When you open a highpressure cylinder, the gas can rush into the regulator at the speed of sound. Ifthere is any dirt present in the connections, it will be blasted into theprecision-fitted valve seats, causing them to leak.
This results in a conditionthat is known as creep. Creep occurs when you shut of the regulator but notthe cylinder and gas pressure is still being delivered to the low-pressure side.Regulators are built with a minimum of two relief devices that protectyou and the equipment in the case of regulator creep or high-pressure gasbeing released into the regulator all at once. All regulator gauges haveblowout backs that release the pressure from the back of the gauge before thegauge glass explodes.
Nowadays, most manufacturers use shatterproof plasticinstead of glass. The regulator body is also protected by safety devices.66Blowout disks or spring-loaded relief valves are the two most common typesof devices used. When a blowout disk ruptures, it sounds like a cannon.Spring-loaded relief valves usually make howling or shrieking like noises. Ineither case, your first action, after you recover from your initial fright, shouldbe to turn off the cylinder valve. Remove the regulator and tag it for repair ordisposal.
When opening a gas cylinder, you should just “crack” the valve alittle. This should be done before attaching the regulator and every timethereafter. By opening the cylinder before connecting the regulator, you blowout any dirt or other foreign material that might be in the cylinder nozzle.Also, there is the possibility of a regulator exploding if the cylinder valve isopened rapidly.WARNING: Oil or other petroleum products must never be usedaround oxygen regulators because these products will either cause a regulatorexplosion or fireCutting TorchesThe equipment and accessories for oxygas cutting are the same as foroxygas welding except that you use a cutting torch or a cutting attachmentinstead of a welding torch. The main difference between the cutting torch andthe welding torch is that the cutting torch has an additional tube for highpressure cutting oxygen.
The flow of high-pressure oxygen is controlled froma valve on the handle of the cutting torch. In the standard cutting torch, thevalve may be in the form of a trigger assembly like the one in figure below.On most torches, the cutting oxygen mechanism is designed so the cuttingoxygen can be turned on gradually. The gradual opening of the cuttingoxygen valve is particularly helpful in operations, such as hole piercing andrivet cutting.Torch BodyMostweldingtorches are designed sothe body of the torchcanaccepteitherFig. 6 One piece oxygas cutting torchwelding tips or acutting attachment. Thistype of torch is called a combination torch.
The advantage of this type oftorch is the ease in changing from the welding mode to the cutting mode.There is no need to disconnect the hoses; you just unscrew the welding tipand then screw on the cutting attachment. The high-pressure cutting oxygenis controlled by a lever on the torch handle, as shown in figure below.67Cutting Torch TipsAs in welding, you must use the proper size cutting tip if quality workis to be done. The preheat flames must furnish just the right amount of heat,and the oxygen jet orifice must deliver the correct amount of oxygen at justthe right pressure and velocity to produce a clean cut. All of this must bedone with a minimum consumption of oxygen and fuel gases. Carelessworkers and workers not acquainted with the correct procedures waste bothoxygen and fuel gas.Fig.
7 Combination torchEach manufacturer makes many different types of cutting tips.Although the orifice arrangements and the tips are much the same among themanufacturers, the part of the tip that fits into the torch head often differs indesign.Because of these differences, there is the possibility of having two orthree different types of cutting torches in your kits. Make sure that the cuttingtips match the cutting attachment and ensure that the cutting attachmentmatches the torch body. Figure above shows the different styles of tips, theirorifice arrangements and their uses.
The tips and sears are designed toproduce an even flow of gas and to keep themselves as cool as possible. Theseats must produce leakproof joints. If the joints leak, the preheat gases couldmix with the cutting oxygen or escape to the atmosphere, resulting in poorcuts or the possibility of flashbacks.To make clean and economical cuts, you must keep the tip orifices andpassages clean and free of burrs and slag. If the tips become dirty ormisshapened, they should be put aside for restoration.Vocabularyrighosesparkкакое-л. приспособление, устройство, механизмSyn: apparatus , deviceшлангискра68igniterwrenchoutfitpressure gaugeleakorificesingle-stage(regulator)flashback20воспламенительгаечный ключагрегат, оборудование, принадлежности, набор(приборов, инструментов)манометртечь, протечка, утечкаотверстиеоднокамерныйобратный удар пламени (проникающий в шлангсварочной горелки)Read the texts above more carefully and complete the sentences.1.
The most common devices for pressure reduction are … and …2. Regulators control pressure and …3. Regulators have two gauges: one is for indicating the cylinder pressure andthe other is for indicating …4. Psig is an acronym from …5. Psig is used to measure …6. Valve leaks in regulators can be caused by …7. A combination torch is a torch which can accept either welding tips or …8. It is necessary to keep the tip orifices and passages clean and free of …21Look at the pictures of torches on pages 67-68 and tell about theirdesign.Reading 522Read the detailed instruction for Setting up the equipment for oxygaswelding and continue filling in the table below.Instructions(What should be done)When using fuel and oxygen tanksthey should be fastened securely to awall, a post or a portable cart in anupright position.Precautions(What shouldn’t be done)An oxygen tank should never bemoved around without the valve capscrewed in place.69Setting up the equipmentWhen using fuel and oxygentanks they should be fastenedsecurely to a wall, a post or aFig.
8portable cart in an upright position.Oxygen Rich Butane Blow Torch Flame An oxygen tank is especiallydangerous for the reason that theoxygen is at a pressure of 21 MPa (3000 lbf/in² = 200 atmospheres) when fulland if the tank falls over and the valve strikes something and is knocked off,the tank will become an unguided and unpredictable missile powered by thecompressed oxygen. It is for thisreason that an oxygen tank shouldnever be moved around without thevalve cap screwed in place.Fig. 9Never lay the acetylene tankFuel Rich Butane Blow Torch Flame down while being used, as the acetonewould start to come out through the valve.
If it was laid down while beingtransported, it must be set upright, valve on top.After the oxygen tank is securely fastened, remove the valve cap. Withthe valve opening pointed away from the welder, open the valve slightly forjust a moment and then close it. This serves two purposes. For one, it blowsout any dirt or dust that may have settled in the valve. This dirt wouldotherwise end up in the regulator and shorten its life and accuracy. Foranother, when a tank is filled, the worker has a tendency to tighten the valvesecurely to make certain it is closed completely. It is better to break it loosenow than when the regulator is in place. Attach the oxygen regulator andtighten the nut.
Never use pliers, as the pliers will soon damage the brass nut;always use a wrench. Also, there is a tendency of welders to over tighten thenut. If it is not leaking, then it is tight enough. If a great amount of torque isneeded to stop it leaking, or if it will not stop leaking in spite of any amountof tightening, then there is something wrong with the nut, the gasket or thevalve.Attach the fuel regulator to the fuel tank in the same manner. The nuton the fuel regulator usually has left hand threads.Attach the flexible hoses from the regulators to the torch. The oxygenhose is usually colored green and the fuel hose red. The fuel hose has lefthand threaded connectors at both ends and the oxygen has right handthreaded connectors.With the valves on the torch closed, and the knobs on the regulatorsscrewed out until loose (0 setting), open the valves on the fuel and oxygen70tanks. Open the oxygen valve slightly and then wait while the high pressuregauge on the regulator stops rising.
Then open the valve fully, until it stopsturning. This is a back stop valve. Turning the valve all of the way outprevents leakage through the packing of the valve.Open the fuel valve also. Only open an acetylene valve one quarterturn. This helps prevent the acetylene from being drawn off too quickly. Ifacetylene 'bubbles' too rapidly from the acetone, it might become unstable.Open the valve on a LPG tank out completely as on an oxygen tank and forthe same reasons.If there are any leaks in the connections, regulators or torch, or anyother faults with the equipment, a safety hazard exists.
The equipment shouldnot be used.Never oil an oxygen regulator. It will cause a fire or explosion — solidbrass regulators can be blown apart from the force. Keep oxygen away fromall combustibles.After this preparation, set the regulators at the desired pressure. Foracetylene, this should never be more than 103 kPa (15 lbf/in²). To prevent alarge yellow, sooty flame when first lighting the torch, open both the fuel andthe oxygen valves (more fuel than oxygen), and light a flame with a 'striker'or by some other means. After the flame is adjusted to the proper size, openthe oxygen valve and adjust it to give the desired balance of fuel and oxygen.Usually a neutral flame is used: this is a flame where the fuel and oxygensupplied to the torch tip are both completely combined with each other.
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