64 



VETERINARY HYGIENE 



of the water-container the water is soon evaporated when in exposed 

 places; the bell is easily broken. This trap may be found in 

 old buildings. 



Grease Traps. Grease traps are used for the purpose of con- 



FIG. 29. A Grease Box with a sediment pan, a ventilated inlet and a sealed outlet, 

 trolling the passage of grease from the house sink into the drain. 

 Hot grease on entering the cold water in a pipe or trap solidifies 

 and is apt to cause a blockage. There are two methods of treating 

 this nuisance. The grease may be retained in a trap and be period- 

 ically removed or it may be passed into a trap so designed that the 

 incoming water breaks up the film of solid grease that forms on 

 the top of the water so that it is carried away in small lumps to 

 the outfall. Figure 29 illustrates a cast-iron grease trap fitted 

 with a container 

 bucket for the re- 

 moval of the solidified 

 grease. Such a trap 

 should be cleaned out 

 at least once a month. 

 Figure 30 shows a 

 more satisfactory 

 form of grease trap, 

 it is self-cleansing and 

 requires no attention. 

 Grease traps are not 

 necessary for private 

 houses and are not 



FIG. 30. A Self-Cleansing Grease Trap with a 

 flushing rim. A. Inlet for Flush. B. Inlet for Waste. 



used to such an extent as formerly. 



JOINING PIPES AND FITTINGS. All joints must be made per- 

 fectly gas and water proof, and the material used for sealing the join 



