Part 7 (2/2)

The foundation for the generator itself should be of brick, stone, concrete or iron, if possible If of wood, they should be extra heavy, located in a dry place and open to circulation of air A board platform is not satisfactory, but the foundation should be of heavy planking or timber to make a firm base and so that the air can circulate around the wood

The generator should stand level and no strain should be placed on any of the pipes or connections or any parts of the generator proper

CHAPTER IV

WELDING INSTRUMENTS

VALVES

_Tank Valves_--The acetylene tank valve is of the needle type, fitted with suitable stuffing box nuts and ending in an exposed square shank to which the special wrench may be fitted when the valve is to be opened or closed

The valve used on Linde oxygen cylinders is also a needle type, but of slightly more complex construction The body of the valve, which screws into the top of the cylinder, has an opening below through which the gas coh which it issues to the torch line A needle scren fro The needle which closes the valve is not connected directly to the threaded member, but fits loosely into it The threaded part is turned by a small hand wheel attached to the upper end When this hand wheel is turned to the left, or up, as far as it will go, opening the valve, a rubber disc is compressed inside of the valve body and this disc serves to prevent leakage of the gas around the spindle

The oxygen valve also includes a safety nut having a sh it closed by a fusibleallows the gas to exert its pressure against a thin copper diaphrag the oxygen to escape into the air

The hand wheel and upper end of the valve e steel cap which covers them when screwed on to the end of the cylinder This cap should always be in place when tanks are received froure 14--Regulating Valve]

_Regulating Valves_--While the pressure in the gas containersfroas is withdrawn, the pressure of the gas admitted to the torch must be held steady and at a definite point This is acco valves, which, while they differ somewhat in details of construction, all operate on the saure 14) carries a union which attaches to the side outlet on the oxygen tank valve The gas passes through this union, following an opening which leads to a large gauge which registers the pressure on the oxygen re in the end of a tube The gas passes through this opening and into the interior of the regulator body Inside of the body is a as causes it to bulge slightly Attached to the diaphragm is a sleeve or an ar placed so that it is directly opposite the sh which the gas is entering, with the result that further flow is prevented

Against the opposite side of the diaphragainst the diaphrag is controlled by the operator through a threaded spindle ending in a wing or ulator body

screwing in on the nut causes the tension on the spring to increase, with a consequent increase of pressure on the side of the diaphragas pressure acted to close the s pressure acts in the opposite direction fro pressure tends to keep the valve open

When the nut is turned way out there is of course, no pressure on the spring side of the diaphragh autoh which it entered If now the tension on the spring be slightly increased, the valve will again open and adulator is just sufficient to overco There will then be a pressure of gas within the regulator that corresponds to the pressure placed on the spring by the operator An opening leads frooing to the torches is drawn froas will, of course, lower the pressure of that re at the point determined by the operator, will overcoain open and ad point This action continues as long as the spring tension reas is taken fro tension will require a greater gas pressure to close the valve and the pressure of that in the regulator will be correspondingly higher

When the regulator is not being used, the hand nut should be unscrewed until no tension reen tank valve is open, the regulator hand nut is slowly screwed in until the spring tension is sufficient to give the required pressure in the torch lines Another gauge is attached to the regulator so that it coauge showing the gas pressure going to the torch It is custoulator which will blow off at a dangerous pressure

In regulating valves and tank valves, as well as all other parts hich the oxygen comes in contact, it is not perer of ignition and explosion The ulator is too delicate to be handled in the ordinary shop and should any trouble or leakage develop in this part of the equipment it should be sent to a company familiar with this class of work for the necessary repairs

Gas ulator until the hand nut is all the way out, because of danger to the regulator itself and to the operator as well

A regulator can only be properly adjusted when the tank valve and torch valves are fully opened

[Illustration: Figure 15--High and Low Pressure Gauges with Regulator]

Acetylene regulators are used in connection with tanks of coas

They are built on exactly the sa valve and operate in a sie only, the low pressure indicator, is used for acetylene regulators, although both high and low pressure ure 15)

TORCHES

Flaen and in no other way When we burn oil or candles or anything else, the as by the heat and is then burned by coen of the air If reater heat andfollows

If the aen, is reduced, the flame becomes smaller and weaker and the couished by shutting off all of its air supply

The oxygen of the combustion only forms one-fifth of the total voluen in place of air, and in equal voluen is as in the proportion that burns to the very best advantage, the flathened and still more heat is developed because of the perfect coas that can be burned in a certain space and within a certain time, the reat areater than that found in any other gaseous fuel, is used by leading this gas to the oxy-acetylene torch and there coen to reatest power and heat than can possibly be produced by any form of combustion of fuels of this kind The heat developed by the flame is about 6300 Fahrenheit and easily melts all the metals, as well as other solids