Pressurised pipe

The method implies injection of a mixture of 3 radioactive tracers each being distributed into one of the 3 phases. The tracers must show such differences in the emitting y-radiation energy spectra that they can be simultaneously detected by on line y-spectrometry. Candidate tracers are Br-82 as bromobenzene for oil, Na-24 or La-140 for water, and Kr-85 for gas. The tracers are injected simultaneously at a constant rate into the flow in the pressurised pipe, and the concentration is detected as series of instantaneous measurements taken downstream as illustrated in figure 2. 

Pressurised pipes for water and gas provide an example of design lives being predicted with confidence on the basis of a large assembly of data, of benchmark quality control tests for existing products, and of two-parameter accelerated testing for new ones. Some types of pipe are particularly sensitive to pressure extremes. Lifetime prediction cannot however take into account poor installation conditions. 

The stresses in a pressurised pipe, free to expand in length, were analysed in Section C.3 of Appendix C. However, buried gas pipe is connected at both ends to immovable objects such as houses, and the surrounding soil prevents the pipe moving laterally. Consequently, the longitudinal strain in the pipe is zero. In this elastic plane strain situation, the hoop strain is given by Eq. (C.21) as... 

Fig. 1.11 Typical creep rupture curve for a pressurised pipe...

In a pressurised pipe, pressure, P, at a given hoop stress, o, is found from... 

Applying leak before burst criteria to pressurised pipes/vessels/containers. 

Sales gas would be piped directly into the national gas distribution network (assuming one exists) and NGL products such as propane and butane can be stored locally in pressurised tanks. NGL products are often distributed by road or rail directly from the gathering station, although if ethane is recovered it is normally delivered by pipeline. 

The usual starting point is to look at how the object is stressed mechanically in service and simulate it - drop a loaded sack, put force on a handle, pressurise a pipe, etc. The more complicated the service stresses are, the more complicated the simulation will become, for example, if a handle may be bent and twisted, this has to be tested together, whereas a sack could fall on its side or a corner and this could be tested sequentially. 

More complex environmental rigs can be illustrated by an arrangement where pipe line components, seals, valves, etc., are mounted as in service and pressurised cyclically with the service fluid. The rig is contained in an enclosure so that elevated or subnormal temperatures can be applied. The degree of acceleration can be varied for both mechanical and environmental factors. 

There are potential hazards associated with use of these for drying hectogram scale samples in the laboratory. The vent pipe is usually of small diameter, so the oven pressurises easily should the contents deflagrate, and has no emergency venting... 

In order to use a programmable freezer it is essential to have a supply of piped liquid nitrogen from a pressurised cylinder and this is also very convenient for topping up liquid nitrogen freezers. 

Failure modes in a pressurised MDPE pipe (a) Ductile parrot s beak fracture (b) brittle section through a welded joint that has failed in a creep rupture test in water at 80 °C. 

The constituents of natural gas should not have deleterious effects on the pipe properties, nor should the gas diffuse through the pipe wall at an excessive rate. Methane and the other hydrocarbons in natural gas, diffuse through polyethylene at a very low rate, that neither causes economic loss, nor dangerous build-up of gas on the outside of the pipe. The maximum daily loss from 1 km of pipe, of 90 mm outer diameter and wall thickness 8.5 mm, pressurised to 1 bar pressure (the partial pressure of methane is 2 bar inside and Obar outside), is 4.41. This is less than 1% of the losses that occur with jointed cast iron pipe, and can be compared with a daily throughput of 2 x 10 1 of gas for a pressure drop of 1 mbar km . ... 

Such calculations show that it is unrealistic to use high strength polymers, such as biaxially oriented PET (Section 4.5.3) for gas pipe the thin pipe walls would have insufficient resistance to soil loads in the period before the gas main is pressurised. 

Installation of a radon sump system equipped with a fan is suggested as the most effective and best choice for high levels of radon existance [29]. For this, a sump which is a small empty space about the volume of a bucket is dug imder the solid floor and a pipe is routed from it to the outside air. The sump and the fan connected at the exit of the pipe to suck air, both help to alter the air pressure below the floor and to pass and to release it harmlessly into the atmosphere. There are also applications where the fan is replaced by a blowing system to facilitate the removal of the remaining of radon in the soil. It is also possible to increase the circulation of air beneath the floor (improved ventilation under suspended timber floors with or without a fan via an air-brick) or at loft level or even by using positive house ventilation as a whole ( positive pressurisation is most effective if house is very air-tight). 

In the event of a loss of coolant, water is first injected from two sub-systems into the distribution headers between the common pump outlet header and the individual channel feeder pipes of the failed circuit from tanks pressurised to 10 MPa which are connected by fast acting valves. At the same time, a third sub-system... 

Treating it as a pressurised thin-walled tube, determine the minimum wall thickness d for an MDPE pipe to meet the specification diameter 104 mm design pressure rating - 400... 

The reactor vessel contains the core, twelve once through steam generators, six canned rotor pumps at a high level in the vessel, and a control rod assembly in each of the 65 fuel assemblies. The top part of the vessel forms the pressuriser with its electric heaters. There is a passive spray system in the pressuriser which takes water from the riser region and sprays it into the steam space in the event of pressure rise in the core. The containment has a novel form of pressure suppression where the water for pressure control is contained in a tank farm connected to the reactor cavity by large diameter pipes. 

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