1202 THE COLLIERY GUARDIAN. June 6, 1913. the static pressure caused by air or gas currents. A combined baffle and flat disc in the measuring piping or channel is used. The disc s is vertical to the air current, disc parallel. The velocity pressure acts upon the opening of the former, whilst the static pressure only influences the latter. The double disc is connected to the indicator or the self-registering apparatus by twin pipes. This apparatus contains in its airtight casing a two floats, g and gv working independently, to which the pressure acting upon the discs s and respectively is conveyed. They are supported by non-volatile oil contained in vessels/ and /. The floats transmit their movements to pointers or registration pens according to whether the apparatus is required with indicator or registration only or with both together. The size and form of the floats are controlled by the local conditions (amount of pressure and velocity). The float chamber g is connected with the disc s, that of the float g with the outer atmosphere, whilst the casing a communicates with disc In the outer casing of the apparatus, therefore, the static pressure prevailing in the pipe r is existing. In the float gx the pressure of the outer atmosphere is acting, and therefore the position will depend upon the pressure or depression in the piping. In the float g the static pressure, in addition to the velocity pressure, acts. Therefore the action on same consists of the difference between the static pressure and static pressure and velocity pressure, i.e., the velocity pressure. Both floats act according to the pressures exercised, and the pointers or writing pens will directly indicate the pressure or depression or the velocity respectively. In case a record of the volume is required, the scale can also be so divided that the volume can be read or registered directly. 0. A. FELL. Mr. Clarence A. Fell, of Dronfield, near Sheffield shows his excellent “ Fire King ” sprinkling shovel, which has already been noticed in the Colliery Guardian, DIAMOND COAL-CUTTER CO. The Diamond Coal-cutter Company, of the Stennard Works, Wakefield, have a large and varied exhibit, but it is obvious that great difficulties have been encountered in getting it together. This, it may be quite readily appreciated, is due to the stress of work on hand at the works. If the machineslack the traditional “exhibition” polish, we do not know that they are any the worse or less attractive, and there are several new features on view. Perhaps the most interesting exhibit is a new model four-cylinder compressed air bar coal-cutter, which has some points of conspicuous novelty. The machine is equipped with patent reversing gear and automatic lubrication. It is interchangeable for electric drive. The bar has an oscillating motion^ which is operated by two worm-driven eccentrics, giving a simple harmonic reciprocating motion on a hollow shaft. A plain jaw clutch is provided for disengaging the bar when desired. This machine is also fitted with an oil pump of simple construction operated by the bar reciprocating motion. The engine has four single acting cylinders working on two cranks, and can be reversed by simply manipulating a handle, this being a very necessary though novel arrangement. Special attention has been given to the lubrication, both the engine and main gears being totally enclosed and self-oiling. The feed is driven through worm gear from the engine crank shaft and is variable. The bar can be swung through an arc of 180 degs. by reduction gears. A 30-horse power direct-current electric disc coal-cutter for longwall work is fitted with Carrick patent motor, having four wound poles and two commutating poles, the armature being laid on heavy ball bearings. The machine is of the totally enclosed gear type, and has many novel points embodied in the design. The gearing is all machine cut, of ample proportions, and mounted on substantial bearings, all end thrust being taken by ball bearings. A reversible valveless oil pump supplies oil to all bearings. The feed gear is neatly arranged and can be varied at will, and the number of working parts have been reduced to a minimum. Special attention has been given to the electrical equip- ment. The controller, which forms part of the gear-case casting, is of the drum type, of massive design, worked by hand wheel, and can be operated from either end of machine. A pivoted cable-connector box of entirely new design is fitted, which by releasing one thumb-screw enables the adaptor to be swung round, so ensuring a straight lead on the trailing cable. This prevents the cable having to be sent over when the machine is cutting back, and entirely obviates any risk of the cable being nipped between the machine and props. The machine is, as a whole, very neat and compact. Either alternating or direct-current motor or four-cylinder compressed-air engine can be fitted to the machine. ' A longwall chain machine is fitted with 25-horse power patented type direct-current compound wound motor having four main wound poles and two commutating poles and armature in ball bearings. This is the firm’s standard swinging jib pattern arranged to cut at floor level, and is also interchangeable for alternating current or compressed air. A new gate-end winch for trailing cable is shown. It is fitted with slipring box and can be arranged for two, three or four core cable. This winch is very portable and compact, and will be found very useful and should effect a great saving in the life of the trailing cable. Blackett’s patent coal-face conveyors driven by electricity and compressed air are also shown, and an improved friction clutch for use with alternating- current motors, together with various patterns and sizes of this company’s well-known safety type gate-end switchboxes and other accessories. A noticeable feature of all the Diamond Company’s latest electrically-driven underground machinery is the provision of safety devices, interlocking of switches, &c., which should remove to some extent the reluctance on the part of many colliery managers to use electricity at the coal face. It is interesting to note that the Diamond Company, who are still extending their works, have now supplied over 800 longwall coal-cutters and 300 face conveyors. WORSLEY MESNE8 IRONWORKS LIMITED^ The Worsley Mesnes Ironworks Limited are showing several of their Melling’s patent specialities. No. 1 shows their well-known patent horizontal controller for the prevention of overspeeding and overwinding in iflig Melling’s Vertical Controller. (Worsley Mesnes Ironworks Limited.) winding machines. This gear has been at work for over three years and has proved itself to be absolutely reliable under all conditons and circumstances. An advantage the Melling controller has is that it applies the brake with a gradual action, if brought into action at any point during the wind, with the exception of the last two revolutions. In the case where an enginewinder happened to forget that he was winding men and brought the cage up at an excessive speed the controller would come into action, the throttle valve would be closed and the brake applied in such a manner that the engines would be brought to rest quietly and gently so that the men riding in the cage would not be thrown about. In many of the overwinding gears on the market the brake is applied instantly when the gear is brought into action, and consequently in this case should the cages be travelling at an excessive speed—the cages reach the speed of a mile a minute—and the brake banged on suddenly, the chances are that the men would be seriously injured by being thrown about. When approaching the end of the wind it is, of course, imperative that the engines should be pulled up more quickly than during the middle portion, consequently should the Melling controller come into operation during the last two revolutions of the drum, the brake then is applied instantly and the cages are brought to rest before the bank is reached, or, in the case of the descending cage, before the cage is bumped on the bottom. It will be noted that the Melling controller is fitted with an auxiliary spring which acts against the governor at slow speeds. This is for the purpose of making the governor very sensitive at slow speeds, and simply by means of a handle on the engineman’s plat- form this degree of sensitiveness can be varied. Thus, should the engineman pull the handle towards him a little, the governor is made more sensitive during the last two revolutions of the engine, and consequently the speed of the drum must be considerably less if the cages are to be landed without the gear coming into operation than would be the case were the handle to be pushed away from the engineman. The slow speed, of course, is used for winding men and the faster speed for winding coal. The chief advantage of this auxiliary spring is, of course, that it does not hamper the speed of the engines during the middle portion of the wind, and only at the end when men are being wound, thus preventing the enginewinder from bumping severely the descending cage on the bottom. The design of the Melling controller is very simple and compact, and all the parts are made exceedingly strong. Another design of controller is shown in a vertical form for use where the available space is limited and where it is desired to control the engine throughout the whole wind. This gear has a number of points about it which are novel and are not to be found on other con- trollers. Both controllers are shown coupled up to a Melling’s patent steam brake engine. This brake engine is built on the same lines as the well-known Melling’s steam reverser. The engines are arranged on the most modern lines and are arranged so that they will occupy very little space on the engine - house floor. The engines can be put to other purposes, such as opening and closing large doors, &c., also for operating large clutches. Another exhibit which the Worsley Mesnes Ironworks Limited are showing on their stand is a coal-cutter shaft —a large number of which they are constantly turning Melling’s Patent Steam Brake Engine. (Worsley Mesnes Ironworks Limited.)