June 6, 1913. THE COLLIERY GUARDIAN. 1193 front of the cylinder there is only one joint of large diameter; whereas, the usual practice is at least two joints of small diameter which may cause bending and straining of the various parts of the machine, especially when working in difficult ground. In the new “ Hardy- Simplex,” on the contrary, the front parts are all enclosed in one solid cover of large diameter, which fits over the cylinder, and is absolutely immovable through side strains. The “ Hardy-Simplex,” B6, will bore holes easily up to 12 ft. in depth where necessary. The best air pressure is from 40 to 75 pounds per square inch. The same machine is equally suitable for solid, hollow or spiral drills, as exhaust air only is used for blowing & “ Hardy Puncher ” Arranged for Cutting near Roof. (Hardy Patent Pick C mpany Limited.) \ 1 r: •• i 'v, ■ “Hardy Puncher” Arranged for Longwall Working. (Hardy Patent Pick Company Limited.) out the dust. We also noted a rather heavier type of this machine (B7), made specially for sinking purposes. Another machine that will be familiar to our readers is the “ Hardy Puncher ” coal-cutter. The “ Hardy Puncher” coal-cutter, which may be used as a longwall coal-cutter, as well as for heading and bord-and-pillar working, consists essentially of a long stroke air-drill, which is fixed in position and held up to its work by means of a solid drawn steel tube provided with powerful jack-screw and toothed head and foot. The machine is seated in a cone cup forming part of a hinged clamp attached loosely to the column. This clamp carries a worm, the teeth of which mesh with those of a worm- wheel bolted rigidly on the column. By turning the worm handle the coal-cutter is caused to move around the column, whilst the forward movement into the coal is obtained by the feed screw controlled by a handle at the back of the machine. For longwall working it is mounted on a sledge, a radial arm being supplied for shearing. Amongst the other numerous exhibits made by this firm, we may mention a propulsion water screen. The special features of this machine are an arrangement of toggle levers, fixed in an oblique position, so as to give a reciprocating motion with a quick return movement, and levers arranged at certain positions to support the body of the machine and allow the spring legs to have an entirely free action. We also noticed a new safety bar hook for haulage purposes, and an automatic tub controller, which can be arranged to control any predetermined number of tubs. PRINCEPS AND CO. Messrs. Princeps and Co. (of Sheffield) have an exhibit which is composed chiefly of their patent oil extractors to work in connection with feed water heaters and exhaust and mixed pressure turbines. During the last three years most of the largest turbine plants in this country and abroad have been fitted with these extractors. Several fine examples are shown of three different types of extractors to work in connection with various conditions in temperatures and pressures. There are also examples of Messrs. Princeps’ patent steam dryers, “ Little Scorcher ” type and No. 1 type. The foregoing specialities are now standardised by most of the principal engine builders in the country and are working successfully in many of the most up-to-date power stations. There are also examples of Princeps’ patent “ wedge ” metallic packing, whilst steam traps and automatic discharges are shown for working under a variety of conditions. HOLDEN AND BROOKE LIMITED. Messrs. Holden and Brooke Limited (of the Sirius Works, West Gorton, Manchester), show examples of their “ Sirius ” centrifugal pumps for various purposes of both the high and low lift types. The former are, as usual, of the multicellular pattern. Some of these are equipped with a patent automatic priming gear. In the delivery main A there is placed a diaphragm B with an opening of such a size as to cause a portion of the water to be by-passed through the pressure regulator C. This regulator consists of a venturi tube D, having converging and diverging nozzles, the entrance to the converging nozzle being protected by a small strainer E. The priming valve F is attached to the delivery main, as shown, and contains a double beat balanced valve G, the operation of which is controlled by the movement of the rubber diaphragm H. The underside of this diaphragm is subjected to the pressure which obtains in the delivery main A, while the upper side is subjected to the pressure existing at the throat of the venturi tube D, since these are connected by means of the pipe K and the small holes drilled in the side of the venturi tube at the throat. The valve F is fitted with an external spindle N, so that its operation can be seen. When the pump is delivering water, some of this flows through tne venturi tube and attains a high velocity through the throat, its pressure at this point being correspondingly reduced, with the result that the pressure on the top of the diaphragm of the valve becomes lower than that on the underside, and the valve is consequently closed against the action of the spring L. If air enters the pump, the flow of water in the delivery main ceases, and also the flow through the venturi tube, with the result that the pressure at the throat becomes equal to that in the delivery main. The pressures on the two sides of the rubber diaphragm now being equalised, the valve is opened by the action of the spring, and the supply of priming water passes from the delivery main into the suction pipe, forcing out any accumulation air through an air discharge pipe fitted with a small non-return valve. Immediately this is done the pump picks up its water again, the flow through the delivery main and venturi tube is re-established, and the priming valve is closed as a result. Another exhibit comprises automatic vacuum discharge for draining vessels under vacuum or alter- nating vacuum and pressure, a special feature of which is the use of large and accessible valves and passages. Leinert’s pent liquid meter is designed to measure by actual weight, and not by volume, the apparatus being s * 1 Section of Automatic Priming Gear. (Messrs. Holden and Brooke Limited.) actuated by the dead weight of the liquid, with the result that the results are not affected by changes in temperature. In cases where exceptional accuracy is desired, a patent regulator is supplied, which has also the function of increasing appreciably the capacity of the meter. Of the obvious uses of this apparatus, its employment with steam plants, to check the efficiency of boilers, the efficiency of engines and the heating value of fuel, may be specially indicated. Brooke’s high-velocity feed-water heaters are based upon the fact that heat transmission is dependent upon maintaining the greatest possible degree of difference in temperature on the two sides of the heating medium. Mention may also le made of the “Expulsor” pulsating steam pump, which possesses a special form of steam head and valve; a variety of injectors and ejectors; and Brooke's well-known “protected seat” steam stop valve, all of which are to be seen in this interesting exhibit. J. NOEL. The “Duplex” shackle pin, shown by Mr. J. Noel, of 1, Romilly-road, Cardiff, is illustrated in the accompanying figure. The pins are of special alloy, tested to 12 tons, and may be fitted to existing shackles by a simple alteration of the eyes. The principle on which the pin proceeds is that the relief or back pin sustains no strain until the front pin has I 7W Duplex” Shackle Pin (J. Noel.) accidentally moved upwards out of gear with the draw- bar. The “ Vigilant ” automatic emergency grip brake, also shown by Mr. Noel, is simply a rocking lever carrying two chambers, each of which contains a powerful spiral spring. LTpon the lever being moved in either direction the brake grip shoes, in mounting the wheel’s curvature, compress the springs up to the point of full diameter; on moving slightly beyond, the springs elongate a little and so lock the lever and brake in position. The lever, &c., are carried by a bracket which is bolted to the angle iron frame bar, and is provided with an easy means for adjusting the brakes to suit the position of the wheel. Affixed to the wheel arms is an emergency catch, which remains closed, so long as the wheel’s revolutions per minute do not exceed the usual maximum when under traction control. Should this be exceeded (as in the case of out-of-control on a gradient} the catch moves outwards by centrifugal force, engages with a lever, and carries the brake on to the wheel.