COAL-GAS UNDER COMPRESSION.
Page 12
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Five-ton Lorry Fully Charged in Four Minutes. Striking Facts and Figures from Glasgow.
IN THE SPRING, the gas committee of the Glasgow Corporation Gas-works decided that experiments with coal-gas as a fuel should be made, and every facility was piaeed at the disposal of the superintendent. A report has recently been handed by him to the gas committee, in which he says that; being interested in the experiments, a considerable amount of time (due regard being paid te the need for the fullest attention being given to the regular work of the department) has been devoted' to these experiments, and he draws attention to the fact that the subject of coal-gas as a fuel for motor vehicles has received a great amount of attention in certain technical journals, and on the part of certain business houses.
, A Quick-charging Battery.
From the management of the North British Railway Co., nine steel cylinders were obtained on loan. The dimensions of these were 6 ft. by 2 ft. 6 ins. (one cylinder)i ' ; 8 ft. 9 ins. by 1 ft. 6 ins. (four cylin ders). 4.ft. 8 ins; by 1 ft. 6 ins. (two cylinders); and 4 ft. 8 ins. by 1 ft. 4 ins. (two cylinders). Each of these had a -I in. connection at the end, the ends being convexed, and each was tested up to 250 lb. pressure per sq.. in. The superintendent fitted the two 4 ft: 8 in. by 1 ft. 6 in. cylinders, one on either side of the chassis of the vehicle upon which the first series, of tests were made,. andone of the 4 ft. 8 in. by 1 ft. 4 in. cylinders at the rear of the chassis, thus obtaining a holding capacity of 400 cubic ft. of gas
at'200 lb. pressiire. . . The other cylinders were coupled together in the yard of thegas-works, for the purpose of forming a
quick-charging battery. This battery, when charged, contains 1785 cubic ft. of gas at 250 lb. pressure. To compress the gas, two force pumps of the singleacting type were made, each 4 ins, in diameter by 14 ins, stroke, working continually and driven by a crank fitted to a small punching machine, which latter is driven by a belt from the workshop shafting. During the time that the motor vehicle is out in the district working, the pumps are compressing the gas into the battery of -cylinders to be ready for the next time the vehicle requires a charge of gas. The time taken by the pump to compress 400 cubic ft. of gas is 80 minutes, and being at a 250 lb. pressure the battery of cylinders will recharge the cylinders on the chassis with 400 cubic ft. of gas in four minutes, thus saving a large amount of time when a vehicle comes in for a recharge. The gas consumed in compressing 400 cubic, ft. of gas is 12 cubic ft.., costing about a halfpenny. The railway companies have practised for many years the method of placing large cylinders of compressed gas on trucks and sending them to various stations to charge the gasholders fitted to railway carriages. The vehicle selected for trial was a 25 h.p. Halley 2-tonner. Unladen, the weight of the vehicle is 3 tons 11 cwt., including 5,1 cwt., the weight of the three gas cylinders and fittings, so that the gross weight was 5 tons 11 ewt: The tests were made over an out-and-hoine journey, the outward journey being Ott an up grade. Comparative tests were made over the same distances with the same vehicle with a measured gallon of petrol as against 400 cubic ft. of gas. A series of tests were made at various loads, ranging from 5 tons 11 cwt., down to the net, vehicle weight of 3 tons 11 cwt., and a table of results was prepared. This table lies before us and shows that 400 ft of compressed gas always carried the vehicle a full two miles further than would a. gallon of petrol, the -average distances being:
400 cubic ft. compressed coal-gas 13.72 miles.
1 gallon petrol ... 11.59 miles.
The running time again was better in the case of coal-gas, the average times per mile over the whole series of tests being :— Coal-gas ... ... 4.68 minutes per mile.
Petrol ... 503 minutes per mile. The costs per vehicle-mile work out as follow, the average load of each set of ten trials being 4i tons:
Coal-gas .932d. per vehicleenile. Petrel ... ... 2.293d. per vehicle-mile.
No adjustments were made during the trials, and no bills were coasted, but all were driven down at a regular speed on the brakes.
Experiments were made in the way of enriching the gas with petrol by two methods: (i) by blowing the gas at •low pressure on to a gallon of petrol in the low pressure tank (that is to say, the ordinary petrol tank) so-as to allow the gas to expand before being taken up by the engine ; and (2) by the gas blowing through a trap in which a measured gallon of petrol has been placed. The trap Mentioned is a 5 ft. length of 4-in. steam piping placed between the pumps and the gas cylinders on the car, so that when the gas cylinders are being charged, any oil or water which may come through from the pumps shall be trapped. This method of enriching did not prove to offer any advantages, as although a slightly greater mileage was obtained from 900 cubic ft. of gas thus enriched, the cost per mile was brought up to a figure varying from 1.4d. to 1.9d., according to the method of enriching.
So far as steel gasholders are concerned, he is oi the opinion that the gas ipilustry should consider thc subject as a further outlet for the use of coal-gas anti as a serious competitor to electricity or petrol in ths commercial life of a city.
The report concludes with an expression of opinion tha' compressed coal-gas for motor vehicles is a practical proposi tion, and with a recommendation that the gas committee o the Glasgow Corporation Gas-works should allow all theh existing motor vehicles to be prepared for gas, and that expert mental cylinders, capable of withstanding 1000 lb. pressure pa e pe: sq. in., be obtained, one to be mounted as a reservoir compressed gas for supplying cylinders on the vehicles, am the other mounted on a chassis to supply any consumer wlif may wish to give the system a trial.