BAIRD &TATLOCK (LONDON) LTD. 



Copper, Constantan Leads. 



These leads are made up as a twin-core cable, one wire being copper and the other constantan. When used 

 with copper, constantan thermo-couples they transfer the " cold-junction " from the thermo-couple to the indicator, 

 just as the compensating leads already described do in the case of platinum thermo-couples. 



5567 T Flexible braided pattern, twin-core copper, constantan cable . . . . . . per yard 



5568 T but enclosed in flexible steel sheathing, to stand rough usage 



per yard 

 5569 T Lead covered twin-core copper, constantan cable . . . . . . 



Switch Boards, intended for installations where more than one thermo-couple is used 

 on the one indicator. 



5570 T For four thermo-couples . . . . 



5571* ten 



PLATINUM RESISTANCE PYROMETERS (2). 



Platinum Resistance Pyrometers are the most accurate form of instrument for recording 

 temperatures between o 1000 C., the readings being very open, so that temperatures 

 can easily be read to i C. 



A complete platinum resistance pyrometer outfit consists of a suitable indicating or recording instrument 

 connected by leads to the pyrometer itself. The essential part of this latter is a coil of fine platinum 

 wire generally called the bulb which must be protected from damage by a suitable protecting tube. This 

 tube may consist of brass or steel for moderate temperatures but must be of porcelain or quartz for high tempera- 

 tures. The coil of wire varies in electrical resistance with its temperature, and therefore the indicator, which is 

 simply a resistance measuring instrument, can be calibrated to read directly in terms of the temperature of the 

 platinum coil. 



The bulb measures about J in. diameter by 2 in. long in our standard instrument, and is connected by platinum 

 lead wires to the terminals at the top of the protecting tube. When the protecting tube or stem will not be subjected 

 to any considerable temperature copper lead wires may be used inside it instead of platinum. 



' 

 5572-5573 



5572 T Whipple Temperature Indicator, - 10 to 1+200 C., graduated every i C. In teak 



case without couple or leads 

 5573 T Ditto, range o to 2200 Fahrenheit, graduated each i F., without couple or leads 



This instrument must be connected to the couple by means of 4-way leads, which may be of any length desired. 

 To take a reading with it the key F is pressed and the movement of the pointer B observed. The pointer will be 

 deflected one way or the other but by turning the handle H in the corresponding direction the pointer can be brought 

 back to its zero position in the centre of the window. When this is the case the temperature can be read off directly 

 from the scale in the window A. The scale is extremely open, being divided every t C. on the standard temperature 

 scale from - 10 to + 1200 C. The necessary current is obtained from the two dry cells c, so that the instrument 

 is entirely self contained. 



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