Water-jacketed glass coil

Coil condenser. An open tube, into which is sealed a glass coil or spiral through which water circulates. The tube is sometimes also surrounded by an outer cooling Jacket. A double coil condenser has two inner coils with circulating water. 

Figure 4.6. Flow-injection manifold employed for the enzymatic determination of urea by potentiometric measurement of pH. The sample S (30 jjlL) is injected into a carrier stream of 1.0 mM TRIS buffer in 0.14 M NaCl (pH 7.70), containing dissolved urease, and then passed to the reaction coil a, placed in a themostated water jacket, where the enzymatic degradation of the injected urea takes place. The sample zone is then led to a capillary glass flowthrough electrode (pH) and finally via the reservoir, housing the reference electrode (REF), to waste, W.

Connect a 2-1. reaction flask to a coil condenser by means of a glass tube 10 to 12 mm. in diameter, as illustrated in Fig. 10. Fill the jacket around the coil condenser with ice and water. To the lower end of the condenser attach a short adapter (35 mm. in diameter) passing into the receiver. The latter is a 500-ml. pyrex extraction flask with a neck about 45 mm. in diameter. Add 250 ml. of... 

The outside coefficient, ho, is quite low for water in a simple open jacket. It can be increased by using agitation nozzles, a spiral baffle in the jacket, or a half-pipe coil welded to the tank [1,2]. The wall resistance is usually negligible for a steel tank, but it may be significant for a thick stainless steel wall or for a glass-lined reactor. 

---