SCIENCE-GOSSIP. 



303 



SOME NEW PHYSICAL APPARATUS. 



By James Quick. 

 {Continued from page 279.) 



Cribb's Double Surface Condenser. 



A MONG the advantages claimed for this form 



of condenser, which has been patented by 



Mr. Cecil H. Cribb, B.Sc, the great efficiency 



calls for marked attention. The condensing sur- 



Fig. 1. 

 Cribb's Double Surface Condenser. 



faces are, owing to the double walls, exceptionally 

 large in proportion to the size of the condenser. 

 The capacity of the condensing space is so small 

 that the whole of the vapour in entering comes 

 immediately in contact with the condensing sur- 

 faces. Much less cooling water is required, and 

 the condenser is of exceedingly small size and 

 weight. 



Fig. 2 is a sectional view of the condenser. The 

 vapour enters through the side neck A into the 

 condensing space B, between the two tubes C 

 and D ; after condensation the distillate passes 

 out through E. The cooling water passes down 

 the tube F into the interior of C, which it fills, 

 and, running over the rim at the top, passes in a 

 thin stream down the outside of D, finally flowing 

 away through the escape pipe G. When used as 

 a reflux condenser, the vapour of course passes 

 up through E. After allowing the liquid to get 

 into full ebullition, so that the air is driven 

 out of the condensing space, the mouth of A 

 may be completely closed with a cork, thus 



avoiding even the possibility of loss with volatile 

 liquids such as ether. The apparatus must 

 obviously always be used in one and the same 

 position, i.e. with its axis vertical. This is a 

 distinct advantage, because it is very easily so 

 supported, and because when thus disposed it 

 takes up a minimum of space on the bench. A 

 series of quantitative trials with the condenser 

 gave the following figures : 



Small metal condenser. Glass condenser. 



65°C. 76°C. 



6o°C. 6i°C. 



6i°C. 



4i°C. 



6,020 



ate } 2,642 4,128 1,017 



47'5°C. 

 35-5°C 

 2,og3 

 355 



Temperature ol\ 



effluent cooling - 52 <1 C. 



water J 



Temperature of\ H . or , 



distillate ...J 4 ° *"" 



C.C. of cooling \ 



water used per - 40,000 40,000 7,200 



hour j 



C.C. of distillate' 



per hour 

 Ratio of quantity \ 



of distillate to I i_ 1 



that of cooling f I5 - 14 q -6g 



water > ° y a 



The metal condenser used in the above experi- 

 ments measured 4J x 1 inches ; the glass condenser 

 4f X ig inches. By 

 comparing efficien- 

 cies it will be seen 

 from these mea- 

 surements that one 

 of these small con- 

 densers is equal in 

 condensing power 

 to a Liebig con- 

 denser of at least 

 five times its size. 



The very thin 

 layer into which 

 the water is spread 

 when pouring down 

 the outside of the 

 condenser greatly 

 facilitates evapora- 

 tion, so that the 

 latent heat of va- 

 porization, which 

 has mainly to be 

 derived from the 

 vapour undergoing 

 condensation, 

 effects a great sav- 

 ing in the cooling water used. This is especially 

 the case with liquids boiling above ioo° C, but may 

 be easily shown in the case of water by cutting 

 down the supply of cooling water to a minimum, 



Fig. 2. 



