Piping resistance

Here is an extremely useful chart for tube and pipe resistances for various metals. 

The reduction in the tensile load capacity of the drill pipe is 311,400 -260,500 = 50,900 lb. That is about 17% of the tensile drill pipe resistance calculated at the minimum yield strength in uniaxial state of stress. For practical purposes, depending upon drilling conditions, a reasonable value of safety factor should be applied. 

When a fluid is flowing through a pipe, resistance to flow is caused by friction. The pipe bore selected for each section must be such that under any operating conditions, the initial head, either static head of oil in the supply tank or the pump delivery pressure, will be adequate to ensure the required flow rate. Additionally, any change of flow rate and consequent variation in loss of head must not adversely affect the operation of the associated oil-burning equipment. 

BISRA tests on galvanised steel pipe buried for five years at five different sites are described by Hudson and Acock The galvanised pipes resisted corrosion rather better than steel at all sites. Galvanised pipes of small diameter are frequently used to provide underground water services in farms and similar establishments, and little trouble is experienced. 

A special adaptation of this analysis was applied by Donachie (D8) to estimate the pipe resistances using field measurements of pressures. In that application the u s correspond to pipe resistances and the x s correspond to the nodal pressures. Using linearized sensitivity information adjustments of u s are made, one at a time, to reduce the discrepancies between calculated and measured pressures according to the least-squares criterion. The Am which causes the largest change in the sum of squares of discrepancies is given precedence over others. 

ISO 4433-3 1997 Thermoplastics pipes - Resistance to liquid chemicals - Classification -Part 3 Unplasticized poly(vinyl chloride) (PVC-U), high-impact poly(vinyl chloride) (PVC-HI) and chlorinated poly(vinyl chloride) (PVC-C) pipes ISO 6259-2 1997 Thermoplastics pipes - Determination of tensile properties - Part 2 Pipes made of unplasticized poly(vinyl chloride) (PVC-U), chlorinated poly(vinyl chloride) (PVC-C) and high-impact poly(vinyl chloride) (PVC-HI)... 

ISO 4433-4 1997 Thermoplastics pipes - Resistance to liquid chemicals - Classification -Part 4 Poly(vinylidene fluoride) (PVDF) pipes ISO 9393-2 1997 Thermoplastics valves - Pressure test methods and requirements - Part 2 Test conditions and basic requirements for PE, PP, PVC-U and PVDF valves ISO 10931-1 1997 Plastics piping systems for industrial applications - Poly(vinylidene fluoride) (PVDF) - Part 1 General... 

Similar to the calculation of pipe-resistance, the pressure drop caused by the gas flow passing through the accelerating tube, -ApXd, can be represented by... 

The manufacturing process and properties of polybutene-1 are comparable to PP. Compared to the aliphatic hydrocarbons, this material is not as inert as PE and PP. Its high burst strength and tear strength are very advantageous for the manufacture of hot water pipes (resistant up to 95 °C). 

Phenolic epoxy 60 50-100 45 min 18 h Two components for low friction on inside of pipes resistant to crude oil containing H2S and C02... 

The line will be in continuous service 365 days/year. The steam is valued at 1.30 per 1000 lb. The thermal conductivity of the lagging is 0.04 Btu/ (hXft2X°F/ft). Steam-film and pipe resistance may be neglected. 

Fittings, pipe, resistances, 95, 98-100 Fixed bed solid catalysis, 596 name reactor, 573 Flash conditions, 375-377 example, 378... 

To understand the mechanism of the turbulent mixing process occurring in pipe reactors, we have to consider first some of the properties of fluid flow in pipes. Resistance to fluid flow in a pipe has two components, the viscous friction of the fluid itself within the pipe, which increases as the fluid viscosity increases, and the pressure differential caused by a liquid level difference or a pressure difference between the two vessels. 

Typical pressure to subcooler Miscellaneous piping resistance 0.5 psi 18.7 psia (129 kPa)... 

Miscellaneous piping resistances Typical pressure at MHE cold end 0.5 psi 83.0 psia (572 kPa)... 

A pressurizing pump fights only pipe resistance. A lift pump must fight pipe resistance and gravity. A lift pump, therefore, must pump harder and faster to overcome the opposition. But how much pressure do we need to fight gravity ... 

For any flow rate, we need a certain amount of energy to push the water against both gravity and pipe resistance. Double that flow rate and the energy required is double the original value plus the additional energy required to combat the fourfold increase in pipe resistance. 

If higher flow rates result in higher energy requirements and increased pipe resistance, that also means that lower flow rates will need less energy and suffer lessened pressure losses. 

Think about it. Once the pipe track is installed, both the static head (vertical distance separating intake and hydro unit) and the pipe resistance are fixed values. Using this one rule of thumb—dynamic head should dip no lower than 70% of the value of static head—an owner/operator can be assured of selecting the right size... 

For steady laminar flow in straight pipes, resistance is given by the Hagen-Poiseuille relationship ... 

Friction in pipes. For straight horizontal pipes resistance to flow arises because of viscous shear or friction at the wall. Dimensional analysis leads to the conclusion that for smooth pipes the pressure drop (scaled to make it dimensionless) is a function only of the Reynolds number. The dimensionless group containing the pressure drop is known as the friction factor ... 

Cathodic protection is optimum within a specific potential range (see Section 13.7), so that the length of pipeline protected by one anode increases as the metallic pipe resistance, Rl, decreases, and coating resistance, z, increases. 

ISO 4433-4 1997 Thermoplastics pipes - Resistance to liquid chemicals - classification -poly(vinylidene fluoride) pipes. 

ISO 4433 1984 Polyolefin pipes - Resistance to chemical fluids - Immersion test method -System for preliminary classification. 

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