SEAL IN TRAPS: The seal traps prevent the passage of foul air or gas through it, though it allows the sewage or waste water to flow through it. The depth o water seal is the vertical distance between the crown and dip of at trap depth of water seal represents its strength or effectiveness. Greater the depth of water seal, more effective s trap The depth of water seal varies from 25mm to 75mm.
CAUSES OF & PRECAUTIONS BREAKING OF SEAL:
Water seal may break due to the following reason.
(1) Faulty joints.
(2) Crack in the bottom of seal.
(3) Creation of partial vacuum in the sewer fittings.
(4)Increase the pressure of sewer gases
(5) Non-use for a prolonged period.
The breaking of the water seal can be prevented by
(l) Connecting the portion between the soil pipe and trap by a vent pipe
(2) Use of anti-siphonage pipe in the building.
Water closets:
The water closet is a sanitary fitting which is designed to receive human excreta directly from the person using it. The room in which it is installed is also sometimes referred ty the term water closet. The water closets are of following two types:
1. Indian type water closet
2. European type water closet
1. Indian Type Water Closet
This is fixed in squatting or silting position. The overall length of this varies from 450 to 675 mm. The width near the one end is 1 50 mm and it is increased to 225 to 280 mm near the other end. The overall height is including the trap is about 400 to 500 mm. It requires at least 10 liters of water for flushing. Hence its flushing rim is connected to a flushing cistern fixed above the water closet. Two foot rests are fixed on either side of the closet. The Indian type is usually made of porcelain. The details are as shown in Fig
2. European Type Water Closet Figure shows the details of a typical European type water closet. It is made of porcelain and fixed above floor level. The pan has flushing rim, which is connected to the flushing cistern. A cover is provided at its top Overall lengths vary from 500 to 600 mm and height 350 to 400 mm
Flushing cistern:
In order to flush the water closets and urinals the arrangement made is called /flushing cistern. These are made of cast-iron or porcelain with a capacity of 5 to 15 liters. It consists of a bell connected to flushing chain through a lever. When the chain is pulled, the bell i lifted up and the water in the tank rushes through the flushing pipe by syphonic action. The float valve now allows the water from the inlet into the cistern and thus the cistern is ready for next flushing. The details are as shown in the Fig
Urinals
The arrangements provided to receive the urine They are mainly two types:
1. Bowl type.
2. Stall or Slab type.
Bowl type: The bowl type has a lipped basin with a flushing rim fixed at a convenient height about 0.6 m. It is flushed through hand operated symphonic type flushing cistern
Stall or Slab type: It comprises of a flat wall with slab with partitions on sides. It has a floor channel to drain off the discharge through trapped outlet. The stall type urinal range may be flushed by automatic flushing cistern with a capacity of 10 to 15 liters. The details are as shown in Fig
