262 THE COLLIERY GUARDIAN February 11, 1916. 29-5 ft., and the condenser pump a capacity of 3,520 gals, against a head of 49 ft. A slide valve and safety valve are fixed in the con- necting pipes between the turbine and condenser, so that, in the event of failure of the condensing plant, the exhaust steam may be led away into the atmosphere. The Steam Accumulator. The accumulator is situated behind the machinery building, and consists of a circular holder (Balcke-Harle type) which can accommodate 10,590 cu. ft. of exhaust steam. This type of accumulator offers the great advantage over the earlier types, that the back pressure in the connected machines, viz., 15 lb. per sq. in. (abs.), is very little higher than if the exhaust passed direct into the atmosphere; and further that the .steam con- sumption of the engines is not increased as is the case with the old hot-water accumulators, which necessitate a back pressure of 18'5 lb. per sq. in., and increase the steam consumption 5 per cent. Moreover, the capacity of this type of accumulator, if designed with sufficient movement of the “ bell,” is much larger than in a similar size of the older type, as the latter must hold a very considerable volume of water in. order to absorb the large mass of steam suddenly delivered when the main winding engines are working. The construction of the accumu- lator is shown clearly in fig. 3. The outer chamber is made of iron plates, and is carried right up to above the highest position of the moving bell. The inner chamber dips into water, thus forming an effective seal between the atmo- sphere and the exhaust steam in the chamber. The pipe connections are clearly shown in the figure, and require no description. Both the outer surfaces of the outside shell and the top surface of the inner- moving shell are well covered with non-con- ducting material, so that even with the accumulator bell in its highest position, and containing its full capacity of exhaust steam, the con- densation of the latter is kept down to a minimum. The inner chamber is prevented . from rising too high out of the seal- ing water by means of a safety valve, which also counteracts the effect of any sudden pressure pro- duced by the opening of the high- pressure steam throttle valve when the accumulator is in the lowest position. In case there is not enough steam entering, and the accumulator falls to the lowest posi- tion, a large air-admission valve will open. In addition, a depth marker is fitted, which in actual practice is the working guide of the accumulator position. The accumulator regulates the supply of exhaust or high pressure steam to the turbine automatically. If the accumulator falls, the revers- ing valve on the turbine is set in operation by means of an electrical release and oil cataracts, whilst the upward movement of the accumu- lator returns the reversing valve to its original position. The Exhaust Steam Main. This main connects up with the winding engine, washery plant engine, compressor engine, classify- ing plant engine, feed pumps, and steam ventilating fan. This only acts as a reserve for an electrical drive, and seldom runs. Arrange- ments are made for coupling up a second compressor engine at a later date. The exhaust steam main is made entirely of wrought iron, and the end connections in general have fixed collars and loose flanges. All the surfaces are well protected with good silica non-conducting material. No special arrangements of bow pipes or expansion joints are installed, as the numerous bends in the main are sufficient to take up all expansion. Arrangements are made so that in case of necessity■, each of the above engines can exhaust freely into atmosphere. The exhaust steam is cleaned in which is fixed in the interior of the steam accumulator. The Water Cooler. The water cooler, which is situated immediately behind the accumulator, is of circular construction, with the water passing from top to bottom, and has a capacity of 192,000 galls, per hour. The framework is con- structed of wrought iron, and the boarding out of tongue-and-groove board. The water is distributed through a series of lattices, by means of suitably arranged distributors. The cooled water flows from the reservoir by gravity into an adjacent tank in the base- ment of the turbine house, from which tank it is drawn by the injection pumps. The Switch Room. As the new turbine house was built directly on to the existing switch room, the old switchboard and Con- special apparatus a nections had to be displaced in the alteration. Previously there was the original switchboard for dealing with the 10,000 volts cable from the Westfalen electricity works, a transformer of 1,250 k.v.a., with a reduction ratio of 10,000 to 2,000 volts, and a second smaller one of 500 k.v.a. and 10,000 to 500 volt reduc- tion. One of these transformers served the 2,000 volt plant standing over, and the other, which was fixed on the gable wall, served the 500 volt plant. These trans- formers have been transferred to the cellar, the middle wall between the switch room and the turbine building have been taken down in order to give better oversight. The foregoing 500 volt plant are brought through in switch castings with fully covered plates. The 2,000 volt switchgear is so arranged that the high tension oil switch, with voltage and ampere correction, are situated in the cellar, and the marble table with the low-tension measuring instruments are fixed on the turbine house floor in the place of the old plant. The oil switches are worked from here by means of iron rods. The Machine Buildings and Foundations. The main turbine house building is built of stone, and occupies an area of 49’2 ft. by 43'5 ft. Largo windows are fixed in the walls, to give abundant natural • an For this two castings were fixed side by side, each 40,000 Fig. 3.—Steam Accumulator. 1450 KW Fig. 4.—Steam-consumption Chart. or ! Exhaust Enirahj:2 light to the interior, including the cellar (16’4 ft. deep). For lifting purposes, a crane is provided, traversing the whole length of the turbine house, at a height of 16’4 ft. This crane has a lifting capacity of 10 tons, and is also fitted with high speed gear to lift about 1 ton. The lower layer of the foundation for the turbo- generator consists wholly of reinforced concrete, and on this rests a heavy concrete layer, 28’5 ft. by 17’8 ft. area, and 3’2 ft. thick. Six columns of 2’62 ft. diameter on which rest concrete blocks, 2’95 ft. thick, carry the ground floor of the turbine and generator. The foundation of the accumulator is also of rein- forced concrete. It rests on a circular ground layer, of 39’4 ft. diameter and 2’3 ft. thick, on which stands a reinforced concrete ring, 2’46 ft. wide, 24’6 ft. diameter, and 6 ft.. high, covered by a dished layer of ferro- concrete. . Openings for the inlet and outlet pipes to the accumulator are provided in the concrete arch. The foundation of the water cooler stands on a hexagonal concrete block strengthened up by iron railing, and is 3’28 ft. thick. The side walls of the cold water reservoir, which are 6’6 ft. high and 2'1 ft. wide, rest on the plate, and carry the cooler framework, which is also supported by various columns in the centre of the reservoir. made, the results of Test Results. After the plant had been in operation for five months, steam consumption tests were which are given in Table I. Table I. No. Exhaust steam. High pressure steam. 1. 2. Duration of test (minutes) Barometer (in.) 62 ... 30'1 ... 62*05 30’1 3. Steam pressure before stop valve (lb. per sq. in. absolute) 14’7 ... 114 4. Temperature before stop valve (Fahr.) 214° ... 339° 5. Steam pressure before first stator (lb. per sq. in. absolute) 6’5 ... 80 6. '1 emperature before first stator (Fahr.) 320° 7. Vacuum in condenser (in.) 28’6 29’2 8. Vacuum, per cent, of theoretical 95’5 ... 96’8 9. Temperature, exhaust chamber (Fahr.) 91 ... 103 10. Condensed water measured (lb.)... 24,244 ... 19,836 11 Condensed steam (lb. per hour) ... 23,408 ... 19,140 12. Guaranteed steam consumption (lb. per hour) .... 27,104 ... 22,000 13. Power generated (kw.) 673’2 ... 1,032’8 14. Power factor (cos 4>) 0'866... 0’822 15. Voltage 2,043 ... 2,062 16. Revolutions per minute 3,050 ... 3,050 17. Exciter power (kw.) 6’35 ... 7’78 18. Power taken by condenser plant motor (horse-power) 54’4 ... 53’8 19. Power factor for above motor (cos ) 0’6 ... 0’6 20. Guaranteed steam consumption (lb. per kw. hour) 40’26 ... 21’5 21. Steam consumption on test (lb. per kw. hour) 35 18’54 22. Steam consumption corrected for guaranteed conditions (lb per kw. hour) 35*86 ... 19 75 23. Guaranteed consumption r< duced by (per cent.) 11 ... 7-4 24. Temperature injection water entering condenser 90° ... 66° . 25. Temperature , injection water leaving condenser 65° ... 76° 26. Temperature condenser water 85° ... 83° The determination of the steam consumption was made by measuring the condensed steam. ” purpose b cfl CL' 8 a: £ 10 iOOOO 20,000 Cail' Li? AH US . 4-5-1 rc-> , ' F* en / 40- 1 -> . £ (1 r> Pc VI < Al KU ST Ti '«,T S R 1 ( Suai >ANT ST6 ■SN» pQH IN L fot-l losR, Z I 4 L H.+. a ^2 ^14. Hi< P P-U i fN < Corincci o ||R- IS* lx $ .k 1 iQ 1 J. 10 - j 3 3 — 1 capable of holding 220 gals, of water at 104 degs. Fahr. -----up to the gauge stop. The water from these tanks passed into a common tank, from which the pumps were fed. On the turbine the pressure and temperature of the steam were measured in front of the starting valve, and in front of the first stator. The state of the vacuum, barometer, and tachometer were also recorded regularly during the test. In taking the electrical readings, instruments were used which had been carefully tested and found correct. The power given out by the generators was measured by the 2-wattmeter process. The consumption of energy by the motors driving the various pumps in connection with the condensing plant was obtained from the ordinary instruments connected to these motors, and checked by the switchboard instru- ments. On the condensing plant, the temperatures of circu- lating and feed water were measured both at the inlet and outlet of the plant. In order to determine whether the plant came up to the guaranteed steam consumption, two tests had to be made, one with exhaust steam, and one with high- pressure steam. Test with Exhaust Steam.—With the specified degree of exhaust, it was possible to generate 673-2 kw. with cos =0-866. During the test 120 kw. of this power was transmitted to the No. 1 pit, and the remaining elec- trical energy was used on the No. 2 pit. The duration of the test was 65 minutes. From fig. 4 it will be seen that the guaranteed steam consumption curve A B, with exhaust steam, allowed a total consumption of steam, at this power, of 27,1041b. per hour, equivalent to 40-26 lb. per kw. hour, with a vacuum equal to 92-95 per cent, of the theoretical. The actual steam consumption, as measured in the