Air valve

“ When the speed of the engine is much increased, the vacuum is increased in the mixing chamber C, which overcomes the tension of the air valve spring O and allows the valve to open and admit more air to the mixing chamber. The action of the auxiliary air valve keeps the mixture uniform at different engine speeds, as it tends to keep the vacuum constant in the mixing chamber. ”

“ The gas valve opens just after the crank is above the back centre and closes just before the front centre is reached, that is, opening a little after the air valve and closing a shade before it, thus every particle of gas is used in the cylinder, due to a draught of air being drawn in after the gas valve has been closed. ”

“ With the gas, as with any other kind of engine, the valve settings are of primary importance. On very small engines it is often the case that only the exhaust valve is operated mechanically.
Again, there are several well-known makes which operate the gas and exhaust mechanically while the air valve is opened by suction alone. Though opinions differ as to which is the best course to take, there can be little doubt that, with all three valves mechanically operated, a greater nicety of adjustment is obtainable than would be otherwise possible. ”

“ The supply of air for filling these is taken from the propeller draught by a slanting aluminium tube to the underside of the envelope, where it meets a longitudinal fabric hose which connects the two ballonet air inlets. Non-return fabric valves known as crab-pots are fitted in this fabric hose on either side of their junction with the air scoop. Two automatic air valves are fitted to the underside of the envelope, one for each ballonet. The air pressure tends to open the valve instead of keeping it shut and to counteract this the spring of the valve is inside the envelope. ”

“ The bolt B has a very small hole bored through it from end to end. When the vacuum is broken slowly, the pressure falls in D as fast as in the pipe; but a sudden inrush of air causes the valve A to be pulled off its seat by the diaphragm C, as the vacuum in D has not been broken to any appreciable extent. Air then rushes into the train pipe through the valve. It is thus evident that the driver controls this valve as effectively as if it were on the engine. These "emergency" valves are sometimes fitted to every vehicle of a train. ”

“ The inlet and exhaust valves are located in the cylinder head, and both valves are mechanically operated by one push-rod and rocker, radial pipes from crank case to inlet valve casing taking the mixture to the cylinders. The exhaust valves are placed on the leading, or air-screw side, of the engine, in order to get the fullest possible cooling effect. ”

“ But in so confined a space it would in a short time necessarily become foul, and unfit for use from frequent contact with the lungs. It was then ejected by a small valve at the bottom of the car—the dense air readily sinking into the thinner atmosphere below. To avoid the inconvenience of making a total vacuum at any moment within the chamber this purification was never accomplished all at once, but in a gradual manner,—the valve being opened only for a few seconds, then closed again, until one or two strokes from the pump of the condenser had supplied the place of the atmosphere ejected. ”

“ The right valve saves fuel, because unnecessary amount of pressure is not needed to force out air, the right valve copes with dirt and dust, prevents floods, requires no adjustment. Air and steam units cannot mix, the valve releases the air. The valves must be all metal five years guarantee, and no adjustment necessary.
The radiator which is recessed in the wall has the advantage of being less visible, but unless you employ heat reflectors you will lose a lot of heat—and even with them you lose some. ”

“ The pressurization switch and valve positions were those established for normal operation and both bleed air valves were open. In the event of fire, the checklist requires these valves be closed, as is also required in the event of a pressurization emergency. ”

“ A ball-float attached to an air valve is located at the right hand of the condenser so that in case the pump should fail to operate from any cause, the injection water will lift the ball-float, which in turn will open the air valve and by discharging the vacuum will prevent the flooding of the engine cylinder with water.
It is a well-known fact that the atmosphere exerts what is usually termed “back pressure” of 14.7 pounds per square inch upon the piston area of a steam engine, also that water converted into steam, may be converted into its original state by condensation. ”

“ This valve being already weighted with the pressure of the air compressed to six atmospheres by the means previously explained, a certain quantity of air is thus forced into the vessel; at this moment, another revolution of the main shaft causes the equilibrium valve at the bottom of the conducting-pipe to be shut, and at the same time opens the exhaust valve at the foot of the vertical column. ”

“ In order that the proportion of air and gasoline vapor may be correct for all motor speeds, provision is made by means of a valve A for the automatic admission of larger quantities of both at high motor speeds. The ducts are open at all times, but the valve is held to its seat by its weight until the suction, increasing as the motor speed increases, is sufficient to lift it and admit a greater volume of air. The valve A is joined to the tube L, hence the latter is raised when the valve is lifted and the ingress of proportionately larger quantities of gasoline is made possible. ”

“ It is economical to combine the pressure [Pg 85] and suction systems by arranging the air compressor to draw air from the vacuum receiver into the compressor cylinders whence it is returned to the pressure line.
Automatic valves keep the pressures in the pressure and vacuum sides of the system within pre-determined limits. “Make up” air is admitted by the automatic opening of an atmospheric valve when the pressure side of the system is low and the vacuum side high, so that the pump is deprived of sufficient air to operate the system efficiently. ”

“ The check valve is entirely automatic. It is held open against the pressure of the water by a spring or a weight, but when the water is in motion is dragged shut, only to spring open again when the pressure is reduced by the escape of the water into the air chamber. ”

“ During the ordinary driving ranges this valve controls the amount of fuel being used, thus providing all the economy possible. This valve is entirely automatic and requires no adjustment.
The passage-way from the mixing chamber to the intake manifold is controlled by a butterfly valve which is called the throttle-valve and is connected to the throttle-lever on the steering wheel as well as to the foot accelerator, its position determining the amount of gas and air or mixture being fed the engine. ”

“ When the valve rises by reason of increased pressure, part of the steam escapes through one ground joint directly into the open air, and part of the steam escapes through the other ground joint into a huddling chamber, and thence into the air through orifices which form an aperture less than the ground joint orifice through which it enters said huddling chamber. ”

“ A.--Yes; and the general arrangement of the valves of double acting air pumps, such as are usual in direct acting screw engines, is that represented in the figure of Penn's trunk engine already described in Chapter I. Each inlet and outlet valve consists of a number of india rubber discs set over a perforated brass plate, and each disc is bound down by a bolt in the middle, which bolt also secures a brass guard set above the disc to prevent it from rising too high. The usual configuration of those valves is that represented in figs. ”

“ When the pipe is only partly filled with water, the valves drop down by their own weight, allowing the air to freely escape; when the water rises above the level of a valve, it is tightly closed by the resulting pressure. There are fourteen of these valves, those on the lower end being designed to allow air to freely enter the pipe in case it should burst in the deeper portion, and thus prevent any collapse from atmospheric pressure. ”

“ It can, however, be run at as high a speed as 140 revolutions per minute. The air is compressed in a water-jacketed, double-acting compression cylinder, to about 55 lb. per square inch --more or less according to the temperature of the cooling water--the inlet valve being worked from a cam on the crank shaft, to insure a full cylinder of air at each stroke, and the outlet valves being self acting, specially constructed to avoid noise in working and breakages, which have given rise to so much annoyance in other cold air machines. ”

“ If there is only one valve, it may occasionally serve as an outlet when the wind is to leeward. By means of this form of valve, the air is projected upwards in a diverging current towards the ceiling. The valve should be placed above the level of one’s head, but not too near the ceiling; as in the latter case, the current of air is driven hard against the ceiling, and falls thence with considerable force towards the floor. A combination of Sheringham’s inlet and Boyle’s mica outlet into the chimney at the opposite side of the room ensures efficient ventilation in a dining-room. ”

“ The Rotatory valve is simply a 'fourway stopcock turning in a cylindrical case in the plane of the instrument, two of its four ways forming part of the main channel, the other two, on its rotating through a quadrant of the circle, admitting the air to the bypath.' This gives great freedom of execution, but is far more expensive and liable to derangement than the Piston valve. ”

“ This valve is used both for the suction of the gas and of the air, as well as for the exhaust, with the result that either of these two essential phases in the operation of the motor can be independently controlled. The valves offer the following advantages: Their tightness increases with the pressure, since they always open toward the interior of the cylinder (Fig. 6) . They have no rubbing surfaces, and need not, therefore, be lubricated. Their opening is controlled by levers provided with quick-acting cams ”

“ When, on the contrary, the operator ceases to blow, the valve is acted upon by the air in the bladder, which, pressing back at f, drives the valve close against the contraction, and effectually closes the aperture. A slight hissing is heard, but when the contraction is well made, and the cork is good, an extremely small quantity of air escapes.
The workman, seated before the table where he has fixed his instrument, blows from time to time, to feed the reservoir or bladder, which, being pressed by a system of strings stretched by a weight, produces an uniform current of air. ”

“ TIRE VALVE.
In all experiences with pneumatic tires you will find water the greatest enemy of leaks, and in all cases where one is of sufficient size to be an annoyance, water will surely locate it. The weak point in most valves seems to lie in the plunger that closes the opening through which the air is admitted. Most valves work on the principle explained in the sketch. When the air is forced in, the plunger A is pushed down, admitting the air into D, and so into the tire ”

“ When the upper board is raised air rushes into the cavity through the valve to fill up the partial vacuum produced; on again depressing the upper board the valve is closed by the air attempting to rush out again, and this air is discharged through the open nozzle with a velocity depending on the pressure exerted. ”

“ The air valves consist of a large number of steel disks resting on circular seatings and held down by springs, which for the delivery valves are so adjusted in strength that they lift and release the air when the desired working pressure has been reached. It is worthy of note that in this engine no attempt is made to make the air pistons air-tight in the usual way by having packing rings set in grooves round the edge, but the piston is made deeper than usual and turned so as to be a very good fit in the cylinder and one or two small grooves are cut round the edge to hold the lubricant. ”

“ The length of stroke must be kept long enough for the movement of the piston to knock over the valve. The valve on the Rio Tinto machine is a piston, or spool valve; on other machines the valve is of the plain D-slide valve type. The Rand "giant" drill has a device to reduce the total air pressure on the back of the valve. ”

“ It thus takes four strokes or two revolutions of the shaft to complete the Otto cycle, the cylinder being used alternately as a pump and a motor, and the engine, when working at full load, thus gives one impulse for every two revolutions. The valves, which are all of the conical-seated lift type, are four in number—charge inlet valve, gas inlet valve, igniting valve, and exhaust valve. The igniting valve is usually termed the timing valve, because it determines the time of the explosion. ”

“ Now if your engine is all right, you can run the pressure up to the point of blowing off, which is from one hundred to one hundred and ten pounds. Most new pop valves, or safety valves, are set at this pressure. I would advise you to fire to this point, to see that your safety is all right. It is not uncommon for a new pop to stick, and as the steam runs up it is well to try it, by pulling the relief lever. If, on letting it go, it stops the escaping, steam at once, it is all right. If, however, the steam continues to escape, the valve sticks in the chamber. ”

“ Therefore, if we accept the definition that a valve is a mechanical appliance for controlling the flow of a liquid or a gas, strictly speaking no such thing as a "valveless" motor exists. Two-cycle motors are sometimes said to be valveless because of the fact that the movement of the piston automatically regulates the flow of the exhaust and intake gases, but in this case the piston is in reality the valve. ”