GAS SUPPLIES

Evening Star, Issue 25893, 10 September 1946, Page 6

GAS SUPPLIES

DUNEDIN IS LUCKY PROBLEMS OP MANAGEMENT “ Dunedin is one of the lucky cities as far as gas is concerned,” said the gas examiner for Otago and Southland. Mr O, H. Keys, talking to a ‘ Star ’ reporter this morning. “Mr H. Horrocks is a particularly fine gas engineer. and through good management there is yery little time when pressures have been too low,” Briefly,, the work of the gas examiner is to see that consumers are getting value fer their money, The gas regulations, incorporated in the Board of Trade Act, J 924, prescribe minimum pressures, minimum calorific value, and a standard of purity to which the product of every gas company must conform, The calorific value is just the heating power inherent in the gas sold, Each gas company declares .to the gas referees a calorific value which it intends to supply, and the year’s average must be within 2 per cent, of this figure. ■ RICH MIXTURE. “ Dunedin is fortunate in this s respect,” commented Mr Keys* “ Dunedin consumers get one of the richest gas supplies in the country.” In the gas which is burnt locally there are 500 British thermal units of heating in each cubic foot. When gas is< made it usually comes from the retorts' more rich than this, and it is broken down to the correct figure by the addition of water gas, which is made by passing steam over red-hot coke. Selling gas which has too much water gas, or is otherwise too low in calorific value, ■is akin to selling watered milk. CHECK OF VALUES. New Zealand follows exactly on English practice in the checking of values.. There is an officially-appointed gas examiner for each of the provinces, and be is required to perform a certain number of tests monthly. From these he furnishes reports to the gas referees, a board located in Wellington, which operates in the interests of the consumer. As soon as there is any departure from the normal, the gas referees take the matter up. During the war, however, the coal supply position was such that many gasworks had difficulty in maintaining pressures and calorific values. It is, of course, much fairer to deliver gas at a low pressure, than to reduce the calorific value. Low-heating gas registers on the meter exactly the same as the richer gas, and the consumer pays for the full amount delivered. TROUBLES IN NORTH.

northern centres the pressure has often sunk to half of that; allowed. On a large number of days in recent months, Wellington pressures have been below the ~ minimum allowed. But, largely due to good management, a parallel situation has been averted here. Auckland is in an even worse position than Wellington, where delays in the arrival of coal nave caused considerable damage to plant, through the cooling and reheating of the linings of retorts. It is good gasworks practice to keep retorts hot all the time at a constant temperature. Linings are fairly costly, ‘being made usually of silica or special fire clay; and besides this, as the 1 plants. ■ are working to capacity, it is a strain on production resources to'replace them. It takes about a week to cool a retort down, and they must be brought to full heat again fairly slowly. Shipping troubles to the North. Island favour this part of the world. When ships are held up because of the West Coast bars or industrial troubles, as much coal aB possible is railed to South Island centres. Reduction of calorific values sometimes has to be undertaken by the gasworks managements. When pressures become too ,low, gas appliances become inefficient, so water gas must be used. Few people realise the number of industrial undertakings depending on gas, and for these gas pressure reductions are even more, serious than they are for the housewife,