18-08-2012, 12:53 PM
Coir Corrugated Roofing Sheet
INTRODUCTION
Asbestos Concrete pipes are made of a mixture of asbestos paste and cement compressed by steel rollers to form a laminated material of great strength and density. its carrying capacity remains substantially constant as when first laid, irrespective of the quality of water. It can be drilled and tapped for connecting but does not have the same strength or suitability for threading as iron and any leakage in the thread will become worse as time passes. However this difficulty can be over come by screwing the ferrules through malleable iron saddles fixed at the point of service conncetions as is the general practice. The pipes are not suitable for use in sulphate soils.
The available safety against bursting under pressure and against failure in longitudinal
Bending, though less than that for spun iron pipes, is nevertheless adequate and increases as the pipe ages. In most cases good bedding of the pipes and the use of flexible joints are of greater importance in preventing failure by bending, than the strength of pipe itself. Flexible joints are used at regular intervals to provide for repairing of pipes if necessary.
BASIS AND PRESUMPTIONS
Pressure Testing: The procedure for the test as adopted generally is as follows
a) At a time one section of the pipe line between two sluice valves is taken up fortesting. The section usually taken is about 500 meters long.
b) One of the valves is closed and the water is admitted into the pipe through the other,manipulating air valves suitably.(If there are no sluice valves in between the section,the end of the section can be sealed temporarily with an end cap having an outletwhich can serve as an air relief vent or for filling the line as may be required. Thepipe line after it is filled, should be allowed to stand for 24 hours before pressuretesting).
c) After filling this sluice valve is closed and the pipe section is isolated.
d) Pressure gauges are fitted at suitable intervals on the crown into the holes meant forthe purpose.
e) The pipe section is then connected to the delivery side of the pump through a smallvalve.
f) The pump is then worked till the pressure inside reaches the designed value which canbe read from the pressure gauges fixed.
g) After the required pressure has been attained, the valves is closed and the pumpdisconnected.
h) The pipe is then kept under the desired pressure during inspection for any defect i.e.leakages at the joints etc. The water will then be emptied through scour valves and defectsobserved in the test will be rectified.
Concrete Pipe Manufacturing
Early in the design of their new concrete pipe manufacturing plant in Chowchilla, California, Piranha Pipe and Precast (formerly Clovis Concrete Pipe) decided to implement several energy-efficient features. A steady increase in demand for the company’s products and the need to remain competitive guided the company’s decision to design and build a new plant. However, because of increasing energy costs, Piranha’s management also decided to design the plant for optimal energy efficiency. The resulting facility is a 25,000 square foot complex with state of the art equipment, including a 50-hp variable speed drive (VSD) compressor, forty skylights reducing lighting demand, an automated process control system staggering energy-intensive tasks and an advanced curing process requiring less energy than conventional processes.