Engineering Data

The illustration on the right is another example of a typical installation of hose in which the movement is horizontal. The purpose of the support is to prevent the hose from sagging and causing failure near the fittings.

TABLE II

TEMPERATURE CORRECTION FACTOR

The recommended Maximum Working Pressure rating given are at a temperature of 20C. Where Hoses are required to operate at a temperature above 20C, a correction factor should be applied to the specified working pressure of the selected Hose. The correction factors are given in Table II

EXAMPLE

A 50 NB Hose is required for a temperature of 300C and working pressure of 20 kg/cm². The specified pressure for 50 NB Single Braid hose is 33 kg/cm². The correction factor at 300 C is 0.61.

Hence the working pressure permissible is 33x0.61 = 20.13 kg/cm². This is higher than the required pressure i.e 20 kg/cm².hence Single Braided Hose is recommended.

PRESSURE LOSS

As a rough estimate, it can be assumed that the pressure loss in Corrugated Hoses is 100% higher than in new welded steel pipes. In strip wound Hoses, it is 20% higher. This means that in the case of Corrugated Hoses as increase in diameter of 15%, and in the case of strip wound Hoses of only 4%, is sufficient to reduce the pressure loss to the value of the pressure loss in steel pipes.

Because of the nature of the bore of a Corrugated Hose, the pressure drops due to greater friction than that of a smooth bore pipe. The chart shows the approximate pressure drop for each size Corrugated Hose related to a flow rate where water is the fluid. To utilize the chart, read off on the base line the flow rate required. Where a vertical line from the selected point on the base line intersects the nominal bore line, the pressure drop is shown on the vertical axis, corresponding to the point of intersection.