Tweet

---

June 16, 1939

---

Mining Machinery

Exhibition at the works of Hugh Wood and Co., Ltd.

An exhibition of underground mining machinery made and handled by the well known North of England firm of Hugh Wood and Co., Ltd., in their new factory at the Team Valley Trading Estate, Gateshead-on-Tyne, was shown to a representative gathering of mine managers and others on Thursday, June 8. The factory itself is in an excellent centre for the distribution of plant and spares to the Midland, Northern, and Scottish coal fields, and the firm has shown much enterprise in acquiring a spacious building amid ideal surroundings and of size ample to deal with manufacturing, erection, and testing of their products before they are dispatched to the mines.

The name of Hugh Wood and Co., Ltd., has within recent years become so well known that when developments in underground machinery were contemplated, it became common to look through their lists to see what new products they had. The firm was founded in 1908 and formed for marketing a special type of auxiliary haulage engine. Post-war years accelerated machine mining and the firm readily got into the step of progress by the manufacture of conveyors and the dealing with coal cutters, pneumatic picks and underground mining plant generally, introducing Cardox and other auxiliaries too numerous to mention. Over the last 25 years their reputation has been built up by constant attention to new things and the improvement of the old to suit new conditions of mine working, the new factory in Team Valley, Gateshead, being a long step forward in their path of progress.

The new factory is characteristic of modern standards in so far as situation, lighting, heating and ventilation is concerned. It consists of a two-storey administrative block facing the main Kingsway-road on the north end of the new trading estate. An open yard about 30 ft. in width runs the width of the factory, between the administrative building and the factory. At the east end of the factory a road vehicle loading dock is provided, while at the other end an internal rail siding runs the full width of the building in a similar manner.

The administrative offices are of excellent design and afford quietness and cleanliness whilst being close to the works. The machine shop is well ventilated and lighted and is equipped with new machine tools of the latest type. Ample floor space is available for storage, for developing mass production, and abundant space for extensions is available.

The factory proper consists of four large bays of steel frame construction, 9 in. brick filled and of neat design. Reinforced granolithic floors occupy the bays and the roof is of weathered flat construction with steel deck, Tentest lined and covered with two layers of composition roofing material.

Storage of material and spare parts is provided at the opposite side to the light assembly bay and adjacent to the heavy erection bay.

The lighting is on generous lines by means of clerestory steel framed sashes and roof lanterns with wall sashes of large area giving in all a natural lighting of 1 to 2.4 of floor space.

Electric lighting is effected by Mercra gas discharge lamps made by the British Thomson-Houston Co., Rugby, these lamps being most suitable for inspecting metals and obviating the more costly form of concentrated lighting whilst aiding general lighting efficiency. The stroposcopic effect of the lamps, likely to be experienced with the high speed machines employed is taken care of by arranging them so that they neutralise each other. The main bay used for erection purposes has twenty-eight 400 watt "Mercra" lamps with "Mazdalux" dispersive fittings mounted at a height of 26 ft. and spaced 30 ft. by 25 ft., so as to give a floor illumination of 8 ft.-candles. The adjoining bay has the machine tools and assembly requirements for lighter work, such as oil-filled rollers, etc. Here 125 watt lamps are used at 11 ft. above floor level, spaced 13 ft. apart, giving 15 ft.-candles 21 ft. from floor level. In accordance with recent factory regulations a special gas-filled lamp is provided at each machine, the possibility of any difficulty arising from any stroposcopic effect is entirely eliminated.

In any modern factory a high standard of heating is essential and the new "Huwood" factory is heated by means of a low pressure hot water mechanically fired boiler with automatic coal feed. This applies both to the works and to the offices, unit heaters being used in the works, while unit radiators are employed in the offices. Electric fans attached to the unit heaters are employed in the factory for summer use.

The main conveyor exhibit consisted of four different well known types of conveyors that have found favour with colliery managements including a simultaneous loading conveyor discharging on to a bottom belt mothergate conveyor, both of which are "Huwood" special developments.

Figs. 7, 8, 10 show the types of standard conveyor and fig. 9 shows the arrangement of the latest "Huwood" simultaneous loading conveyor.

The simultaneous conveyor drive embodied a "Huwood" type SL1 drive head (fig. 11) specially suitable for low seams and fitted with a 10/15 h.p. 960 revs. per min. motor giving a belt speed of 145 ft. per min.

The SL1 head was developed essentially for simultaneous conveying and for bottom belt conveying, special features of the drive being a minimum tension on the conveyor belt and an endless auxiliary drive belt actuated by a 14 in. diameter drum and passing over an outwardly extended pulley.

The main conveyor belt passes over this auxiliary belt and the two belts are pressed together by a spring loaded jockey drum which increases the arc of contact between the main conveyor belt and the auxiliary belt, putting the required initial tension into the auxiliary belt and ensuring freedom of slip for the whole drive, the auxiliary belt serving a dual purpose as it is arranged to deliver outside the head any fines or gummy material which, in the older type of head, normally collects inside the framework and around the drums.

Fig. 11 shows the extended pulley with discharge plate for bringing out and discharging the fines.

The gearbox is a self contained unit easily detachable and having a jaw coupling between the main drum and the gear. The gearbox is of cast iron with detachable M.S. cover plate. Double spur reduction gears are used with 1½ per cent, nickel steel (100 tons tensile) machine cut hardened pinions integral with the shafts. Ball bearings are used throughout with oil splash lubrication.

The main driving drum is 14 in. diameter mounted in self-aligning bearings in a cast iron housing and grease lubricated, the drum being a mild steel shell with cast iron centres. The transmission between the motor and gearbox is by means of a Silentbloc or other flexible coupling which compensates angular and parallel misalignment and the 10-15 h.p. squirrel cage Buxton certified flameproof motor is arranged for remote control, has a 100 amp. plug and socket mounted on the side and carries the gland taking the cable to a push-pull switch fixed in a convenient position or can be arranged for a direct on line starter. Fig. 12 shows the general lay-out of the head.

The sections inside the first part of the simultaneous loading conveyor are of the flat top belt type LF shown in fig. 13. These are in 4 ft. 6 in. lengths comprising only two separate parts, frame, cap and supporting stool, the construction allows any "fines" from the top belt free exit at the sides through vents left below the spill plates. The construction is rigid and as the conveyor is only 5½ in. high to the top belt and 8½in. to the top of the spill plate on the face side, it is suitable for a very low seam.

"Clevis" connections fitted to the sections provide longitudinal rigidity and enable the bridging of swellies to be easily overcome.

The delivery to the mothergate conveyor is arranged by a double plough designed to remove the output from the top belt on the drive side and from the bottom belt on the return side of the conveyor.

The plough frame now much used in place of the drum delivery formerly employed, consists of two built up side plates carrying two heavy type oil filled rollers spaced at a suitable distance apart.

Diagonally between the rollers is set a shaped steel plough which can be adjusted in height, the blade in contact with the belt being lower than the top of the rollers. The belt, after passing under the plough is deflected upwards over the second roller and effective delivery is obtained owing to the pressure of the plough blade on the belt. Any fine dust passing the plough is dealt with by the auxiliary belt in the driving head.

The tail end is of the LT/1 type and is simply an idler drum mounted in a strong frame with eyes fixed to the frame for taking the tension chains and Sylvesters. This simplicity of construction is made possible by the clean condition of the top belt when it returns to the driving head. The drum is of the oil-filled type similar to the "Huwood" conveyor rollers, the only difference being that instead of synthetic rubber, chrome leather seals are used and arrangements are made whereby the oil can frequently be replenished.

The mothergate conveyor working in conjunction with the simultaneous conveyor, fig. 9, is a light duty bottom belt machine semi-troughed FGS type. It is designed to meet the needs of those requiring a machine of rigid type as opposed to separate loose trestles. The sections are 14 ft. long made of 4 in. by 2 in. RS channel side frames joined by cross bracings supporting the rollers. A 14 ft. section can be carried by two men, is easily transported and fixed. Bottom belt rollers are 7 ft. apart and top belt rollers 14 ft. apart. The conveyor is suitable for outputs up to 50 tons per hour. Driving the light duty conveyor was one of the company's SL type heads. This is of heavier design than the SL/1 head used with the simultaneous conveyor as it uses motors up to 25 h.p. as compared with 15 h.p. with the SL/1, but they have many features in common. The auxiliary belt is again used here, but an 18 in. drum is used instead of a 14 in. The head is substantially made, low, compact, and capable of transmitting 25 h.p. with a belt speed of 155 ft. per min.

Parallel with this conveyor was a 24 in. face top loading belt conveyor with tail end drive; this delivered on to the simultaneous conveyor. The sections were of the ST type, specially for use where a covered return belt is required ; it was semi-troughed and can be supplied with or without spill plates. Standard sections are 6 ft. long, 12 in. high over all and consist of a trestle in halves and the covering pan. The trestles facilitate easy and quick inspection of bottom rollers and this helps the threading of the belt after "bumping up." The top belt rollers have a forward inclination on the outside to centralise and control the belt when running. A tripper delivery is employed for delivering the coal to the simultaneous conveyor and this consists of two shaped frames with a delivery drum in a projecting "neb" and allowing the machine to feed the gate conveyor tail end without resort to dinting.

Altogether seven types of conveyor were displayed.

Throughout the conveyors on exhibition was to be seen one of the most satisfactory developments and one of the soundest engineering jobs that the firm of Hugh Wood and Co., Ltd., have ever brought out — the "Huwood" oil-filled roller. Few people engaged in the practice of mining would deny that improvements in conveyor rollers are long overdue, or that their rapid wear and cost of replacement have very often condemned a conveyor. Although the invention of some type of roller, in which oil filling as opposed to grease filling could be applied, has been the aim of conveyor manufacturers for almost half a century, it was only recently that such an invention became possible, when a suitable type of oil seal was discovered.

In fig. 14 the spindle A is accurately machined with flattened ends to fit into a lock on the conveyor sides, the end caps B are machined to take the spindle A, synthetic oil impervious ring C, ball bearing D, synthetic ring E and inner oil containing sleeve F which is filled with medium heavy oil. The synthetic rings are a new product having a coefficient of friction of 1/4 that of best chrome leather. The machine parts of the steel sleeve F are coated with a special solution and the whole are pressed together forming an oil tight container from the cover B to the sleeve F allowing free oil only to the ball races. The outer drum G is of steel and the end covers are die cast of rustless zinc base alloy. These rollers are light and have been proved satisfactory, 70,000 being in use, some have been running for over two years and have not had oil replacement. Another important feature observed was that all rollers are of equal diameter thus saving the wear of belts and in the trough conveyors the rollers are of ample length and few in number, whilst providing ample support for the belts.

The Simpson-Fisher arch support was an exhibit which used a design, the theory of which is based on the contention that lateral pressure of the sides of a roadway is roughly proportional to the force opposing the pressure of the roof and floor. It is assumed that no trouble will be experienced from side thrust if the roof and floor pressures be not resisted.

The "S.F." steel arch consists of two normal H girder steel arch sections joined at the top by fish-plates, and set perpendicular to right angle invert arch of the same section, means being provided to allow the legs of the normal arch to slide down the invert arch, and thus yield to roof pressure. The essential part of the invention is to be found in the means whereby the sliding action is accomplished. It had previously been found from experiment that ordinary clamps alone were quite inadequate for the purpose, as they did not permit of a regular and vertical settlement and because the amount of friction they set up was too great where a large degree of subsidence was in progress. This difficulty is overcome in the "S.F." arch, by a special roller carriage, consisting of two plates which grip the outside faces of the girders and fitted with rollers to work against the webs of the girders on either side. An upward arm from the two plates carries an anchor bolt, which provides an additional steadying effect, and lying as it does over the upper end of the inverted limb, maintains the roller clamp in position, and also provides resistance to floor pressure.

The object of this device is not so much to oppose resistance to pressure by exerting a gripping action on the girders, as to allow of their telescoping in perfect line. This begins to happen when the pressure is just under rupturing capacity of the arch itself, the rollers being tightened to such a degree as to begin to work at this stage.

The legs of the normal arch and the invert arch are separated by a piece of hard wood, fitting in the web of the respective arches — the normal arch sliding down this wood block.

Fig. 15 shows the fitting for jointing the arch members, and fig. 16 shows the joint arrangement.

Various types of coal and stone drills, both of electricity and compressed air formed interesting exhibits. A number of percussive rotary stone drills were shown along with rods, bits and drill boxes. The importance of weight reduction, simplification and standardisation was shown on the four main types. The XC is arranged with a high striking speed and rotation for fast drilling in coal, while the XSM, XSH and RV-18 are specially designed for hard coal and stone. "Huwood" electric drills have already attained a fine reputation for service, examples of the two different types being shown prominently at the exhibition, the coal and the stone drill. An interesting feature of these drills is the conversion of the normal 40/50 cycle electricity supply to a frequency of 120/150 cycles which admits the employment of a high torque motor; the change of frequency is accomplished by means of an MU-10 gate-end box from which two drills can be worked at any one time. Both drills are difficult to stall and are designed to allow of easy manoeuvring. The coal drill is purely a hand machine, but the stone drill is arranged for attachment to an ordinary prop from which it is fed into the stone by means of a screw feed and ratchet operating gear. Although faster drilling can be obtained from the coal drill, the stone drill has been used as an all-service machine.

Shown in conjunction with the electric drills were a number of "Cutanit" drilling bits. These are tipped with the very hard "Cutanit" steels and are of different shapes, suitable for drilling in coal and stone of varying hardness or for holes in which "Cardox" shells are to be used.

One of the most striking advances which has been made in recent years is to be seen in the progress of pneumatic picks, and of the various types available none has proved more popular than the "Cross" pick, a number of examples of which were on view. These picks covered the whole gamut of mining conditions and were arranged in four different sizes, M-37B, BC-40, BB-40 and V-l. These were shown together with their appropriate steels and certain other pneumatic pick products such as the splitter, in which special tools are used, and the pneumatic spade.

A selection of Ingersoll-Rand two-stage, air cooled, semi-portable air compressors was on view. These were variously driven by fin cooled, or fan ventilated and totally enclosed motors, coupled to the compressor by a V rope drive or direct flexible coupling, the compressors being made up with two low pressure and one high pressure cylinders radially connected to the crank, the cylinders being air fin cooled and fitted with single acting pistons. Inlet and discharge valves of the channel type are fitted; these afford silent operation and free air passage, resulting in minimum temperature rise, the channels and springs being of non-corrosive stainless steel, ensuring long life. Splash lubrication is provided in the enclosed crank case for the pistons, main bearings, and connecting rods, and the discharge air from the low pressure cylinders is air cooled by an intercooler whose air circulation is assisted by a six bladed fan directly mounted on the crankshaft, and this disperses air to both the high pressure and low pressure cylinders. An air intake filter is fitted as common to the low pressure cylinders, and the whole is mounted on a steel bedplate.

It was declared that a two stage machine of this kind would deliver 20 per cent. more air for equal piston displacement than a single stage machine and the final discharge temperature would be reduced by 200 deg. Fahr. in comparison.

Automatic air pressure control could be fitted with direct on-line switch for the smaller unit or contactor gear control for the larger machine, so ensuring continuous operation when the demand for air is intermittent.

The compressors have a range of 61 to 360 cu. ft. of delivered air at 100 lb. per sq. in. pressure, developing 14 to 82 h.p. at 870 revs, per min. for the rope driven unit, and 51 to 300 cu. ft. discharge at equal pressure with 12 to 69 h.p. at 725 revs, per min. for the direct coupled unit. D.C. motors can be fitted but these would operate at 870 revs, per min.

For a.c. supply the slipring type of motor was used (flameproof where required) the controller being of the stator and rotor type. Squirrel cage motors with auto-transformer starters or Trislot motors with star-delta starters have also been used.

Examples of "Everite" asbestos-cement pressure pipes were exhibited along with the various fittings made by Turners Asbestos Cement Co., for whom Hugh Wood are distributors; these have been largely used by water companies and on recent large Government factories where corrosive water is to be dealt with. Screwed joints made entirely of asbestos cement can be obtained or bolted joints can be employed. They are quickly laid and are flexible to a degree, enabling curves to be negotiated. Care should be exercised in installation to ensure ample anchorage at direction changes in the pipe-lines, especially when the pipes are used for high pressures; they are not suitable for temperatures above 150 deg. Fahr., where used for liquids or moist gases. Pipes can be obtained suitable for pressures up to 800 ft. head.

A standard Saunders valve was on view. This is a well known streamlined product of the fullway type with diaphragm opening and closing. The working parts are not in contact with the contents of the pipes they have to control and gland leakages are avoided by the construction ; the diaphragm is of flexible synthetic rubber, and is the only part liable to need replacement after long service.

Protective equipment for miners was also a well known product displayed. Such has been approved by the Mines Research Board and improvements to hats enabling linings to be easily renewed, better shaped peaks and more suitable position for the lamp holder have been embodied in the newer types, all adding to the comfort and efficiency of the wearer.

Flameproof plugs and sockets to B.S.S. 279 were available for examination and these were of sound construction and approved by the Mines Department. The use of these as standard to coal cutters and other gear enables a great saving in renewals and spares, both in the plugs themselves and in the trailing cables, as they then become interchangeable and time is allowed to effect repairs to cables with but few in stock.

Unicone joints and fittings of the plain and instantaneous type were to be seen, the latter consisting of two parts only without bolts and providing a joint deviation allowing +-6 deg. in the pipe-line without leakages under a pressure of 300 lb. per sq. in.

Huwood roll-alloy coal cutter chains and specially constructed jibs were a feature of the show and a self-acting tub axle greaser which efficiently greases the axles, irrespective of the speed at which they are travelling, was a simple and practical device on view.

The exhibition was a credit to the firm and much interest was taken in the exhibits by a critical gathering of mining engineers, who never fail to voice their opinions. Mr. Hugh Wood kindly placed his staff at the disposal of his visitors and took an active part in explaining the manufacturing processes, carried out by some excellent machinery he had installed. We acknowledge our indebtedness to him for allowing us to visit the works.