Radiators should not be fixed directly on to the main heating pipe, but always on branches of smaller diameter leading from the flow pipe to one end of the radiator and back to the main return pipe from the other end; they may then be easily controlled by a valve placed on the branch from the flow pipe.
In addition to these, there exists in the interior of the dorsal valve of some genera a variously modified, thin, calcified, ribbon-shaped skeleton for the support of the ciliated arms, and the form of this ribbon serves as one of the chief generic characters of both recent and extinct forms. This brachial skeleton is more developed in some genera than in others.
Y g g The air passes through a reducing valve from the main to an auxiliary tank, in which the pressure is, say, 125 lb, and thence to the driving cylinders.
- A, antenna; P S, jigger or oscillation transformer; C, condenser; 0, Fleming oscillation valve; B, working battery; T, telephone; R, rheostat; E, earth-plate.
In the Webb compound the driver opened communication from the high-pressure exhaust pipe to the blast-pipe, and at the same time opened a valve giving a supply of steam from the boiler direct to the lowpressure valve chest.
A controlling valve enables the supply of steam to the low-pressure cylinders to be supplemented by boiler steam at a reduced pressure.
In length but is sometimes as much as 15 or 20 ft., and as its valve-stem projects downwards beyond the bottom, it empties itself when rested upon the bottom of the waste-trough.
The lower cut is of a skip for either ore or water; note valve in bottom.
If each distributing flue is connected by means of a mixing valve with a cold-air flue, the warmth of the incoming air can be regulated nicely.
Internally they are found to consist of a lamina twisted upon itself, and externally they generally exhibit a tortuous structure, produced, before the cloaca was reached, by the spiral valve of a compressed small intestine (as in skates, sharks and dog-fishes); the surface shows also vascular impressions and corrugations due to the same cause.
Distribution of steam is effected by a slide valve, sometimes fitted with a balancing device, and sometimes formed into a piston valve.
Generally steam from the boiler is admitted direct to the low-pressure cylinder through a reducing valve, and valves and devices are used to prevent the steam so admitted acting as a back pressure on the high-pressure cylinder.
The distribution of steam to both cylinders is effected by one piston-valve operated by a link motion, so that there is considerable mechanical simplicity in the arrangement.
The former is often a rich oil-gas, stored in steel reservoirs under the coaches at a pressure of six or seven atmospheres, and passed through a reducing valve to the burners; these used to be of the ordinary fish-tail type, but inverted incandescent mantles are coming into increasing use.
The throttle-valve is opened or closed by turning a grooved vertical pulley by means of an endless cord, called the telegraph, passing round another pulley fixed upon the " headache-post," and is thus under the control of the driller working in the derrick.
" The ordinary sand-pump or bailer, consists of a plain cylinder of light galvanized iron with a bail at the top and a stem-valve at the bottom.
In this patent, the distillation is described as being conducted in a vessel having a loaded valve or a partially closed stop-cock, through which the confined vapour escapes under any desired pressure.
Without any valve between them - the space in the still and condenser not occupied by liquid being charged with air, carbon dioxide or other gas, under the required pressure, and the condenser being provided with a regulated outlet for condensed liquid.
He was said to be the inventor of a kind of flying-machine, a wooden pigeon balanced by a weight suspended from a pulley, and set in motion by compressed air escaping from a valve.'
It has been argued that the Underground Railroad delayed the final decision of the slavery question, inasmuch as it was a "safety valve"; for, without it, the more intelligent and capable of the negro slaves would, it is asserted, have become the leaders of insurrections in the South, and would not have been removed from the places where they could have done most damage.
Interior of dorsal valve, showing muscular impressions and labial appendages.
The valves are also in some species very unequal in their respective thickness, as may be seen in Productus (Daviesiella) 1 llangollensis, Davidsonia verneuilii, &c., and while the space allotted to the animal is very great in many species, as in Terebratula sphaeroidalis, it is very small in others belonging to Stro phomena, Leptaena, Chonetes, &c. The ventral valve is usually the thickest, and in some forms is six or seven times as great as the opposite one.
The ventral valve is usually the larger, and in many genera, such as Terebratula and Rhynchonella, has a prominent beak or umbo, with a circular or otherwise shaped foramen at or near its extremity, partly bounded by one or two plates, termed a deltidium.
3, 4) the interior of the dorsal valve is variously furrowed to receive the lophophore folded in two or more lobes.
The ventral valve in many of the genera is provided with two curved hinge-teeth, which fit into corresponding sockets in the opposite valve, so that the valves cannot be separated without breaking one of the teeth.
Each valve of the shell is lined by a mantle which contains prolongations of the body cavity.
Interior of dorsal valve, to show the position of the labial appendages.
In Discinisca they are provided with a muscular valve placed at their point of origin.
The divaricators proper are stated by Hancock to arise from the ventral valve, one on each side, a little in advance of and close to the adductors, and after rapidly diminishing in size become attached to the cardinal process, a space or prominence between the sockets in the dorsal valve.
The accessory divaricators are, according to the same authority, a pair of small muscles which have their ends attached to the ventral valve, one on each side of the median line, a little behind the united basis of the adductors, and again to the extreme point of the cardinal process.
Of the peduncle, and to become attached by one pair of their extremities to the ventral valve, one on each side and a little behind the expanded base of the divaricators.
E is a valve in the inlet pipe opening into the cylinder; and A the piston is perforated by one or more holes, each fitted with valves opening outwards on its upper surface.
On raising the piston, the valve F remains closed and a vacuum tends to be created in the cylinder, but the pressure of the atmosphere forces the liquid up the tube D and it raises the valve E and passes into the cylinder.
On reversing the motion the valve E closes and the liquid is forced through the valve F to the upper part of the cylinder.
For high heads the water cylinders, valves and valve chambers are specially constructed to withstand heavy pressures, water being sometimes raised in a single lift to heights of more than 2000 ft.
The proboscis, passing down this groove to the spur, becomes dusted with pollen; as it is drawn back, it presses up the lip-like valve of the stigma so that no pollen can enter the stigmatic chamber; but as it enters the next flower it leaves some pollen on the upper surface of the valve, and thus cross-fertilization is effected.
The vessel is filled through the spout, and the water is driven out by the pressure of the gas it contains, when the valve is opened.
Dorsal valve, showing calcareous spiral coils.
It subsequently becomes attached to the ventral valve, and develops into the pseudodeltidium, in the Neotremata and the Protremata.
Ventral valve, and does Phylembryo stage.
The pedicle passes out at right angles to the plane of junction of the valves of the shell; the opening is confined to the ventral valve, and may take the form of a slit, or may be closed by the development of a special plate called the listrium, or by a pseudo-deltidium.
An objectionable feature of the system of allowing the vapour to escape from the still to the condenser through a loaded valve, viz: the irregularity of the distillation, is thus removed, and the benefits of regular vaporization and condensation under high pressure are obtained.