648 PROCEEDINGS OF SECTION H. 



the plug, which can be opened when required by depressing the ball. 

 This is done with a small disk attached to a rod passing through the 

 centre of the hydrant tube. When the mains are empty the plugs 

 open automatically, and hence act as air valves. Whilst this is an 

 advantage in the case of roadway fireplugs, it is accompanied by the 

 great disadvantage that under such conditions any street drainage 

 or filth which may have accumulated round the plug and under the 

 cover obtains direct access to the water mains. 



Various types of ball have been used, the principal ones being 

 indiarubber, gutta-percha, ebonite, and wood. Wooden balls covered 

 with about three-sixteenths of rubber are very satisfactory, and cost 

 about Ss. each for Sin. balls. Gutta-percha balls are liable to soften 

 and deform with heat, and under special circumstances have been 

 blown through the valve seats. Ebonite is satisfactory in cases (as 

 with pillar plugs) where grit cannot accumulate. Experiments are 

 being tried with wooden plugs which are very promising, and if success- 

 ful will result in considerable economy, as they cost about 6d. each, 

 whereas some of the others cost 4s. 6d. each. 



With fireplugs of the Bateman and Moore type the pressure be- 

 tween valve and valve seat is limited by the water pressure, whereas 

 with the screw-down type the act of closing necessarily places consider- 

 able stresses upon the valve, valve spindle, and connections between 

 these parts and the valve seat ; and with leaky or imperfectly fitting 

 valves the intensity of such stresses will be limited only by the strength 

 of the valve key and of the man working the same. As the force 

 applied by such man acts at a considerable leverage, evidently such 

 stresses will be large, and unless the parts are made of ample strength 

 breakages may be expected. 



The ordinary Bateman and Moore fireplug has a rather small 

 chamber, and the waterway at the bottom of the same is considerably 

 restricted by stops provided to prevent the ball dropping into the 

 main. The writer has designed a new type of valve chamber giving 

 ample waterway round the ball, which is kept centred by four vertical 

 fins. This chamber is also made of ample depth, so that the ball can- 

 not be forced down on the stops, as is frequently done with the Bate- 

 man and Moore plug, where the hydrant rod is of excessive length. 

 The discharging capacities of the Bateman and Moore plugs in such 

 cases are reduced, and very frequently the balls are damaged and have 

 to be renewed. When tested at Geelong the writer's fireplug was 

 found to pass 25 per cent, more water than a Bateman and Moore 

 plug under similar conditions, the plugs being on a Sin. branch one chain 

 in length and connected to a Tin. main having 821bs. pressure. 



Pillar fireplugs of the screw-down type are extensively used in 

 Adelaide. In this type the valve gear is placed on top of a hollow 

 pillar, up which the water passes, and connections are provided for 

 attaching the hose to the pillar, no intermediate portable hydrant 

 being required. Samples of the Adelaide pillars were supplied to the 

 Melbourne authorities, who adopted a modified design, preserving 

 the upward pressure system of the Bateman and Moore. The design 



