Piping purging

Use double walled pipe with annular nitrogen purge and monitoring capabilities... 

Open expander/eompressor ease drains and expander/eompressor piping vents to vent any liquid and air from ease and proeess piping. (Allow eases to purge 1-2 min, then elose expander ease drains.)... 

Activate Purge and pressurize Vessel entry pro- Purge to less than 1 % Ensure piping is Check dewpoint. 

Significant errors will arise if gas purity is not accounted for. It should be noted that the code lays down no conditions for this, and a figure of 99 / or better should be targeted. In order to obtain a good purity at the start, all pipe joints should be taped and the system evacuated to a low vacuum several times with intermediated purging with the test gas to remove the residual contaminants. 

Prior to entry into large tanks containing inert medium, ensure that pipes to the tank from cryogen storage are blanked off or positively closed off purge with air and check oxygen levels. 

Filtrates that generally do not require a sharp separation between the mother and wash filtrates. Some complex valves, however, enable atmospheric purging of the sectors and internal piping to facilitate a sharp separation of filtrates,... 

The suction shut-down bypass valve is used to purge the piping system of air prior to compressor start-up. This valve is small to prevent high gas purge rates from spinning the impellers. 

At high points in piping, vent valves are required to remove air for hydrotesting and for purging the system. At low points, drain valves are required to drain liquids out of the system to perform maintenance. Normally, vent and drain valves are 14-in. or i-in. ball valves. 

About two-thirds of the N2 produced industrially is supplied as a gas, mainly in pipes but also in cylinders under pressure. The remaining one-third is supplied as liquid N2 since this is also a very convenient source of the dry gas. The main use is as an inert atmosphere in the iron and steel industry and in many other metallurgical and chemical processes where the presence of air would involve fire or explosion hazards or unacceptable oxidation of products. Thus, it is extensively used as a purge in petrochemical reactors and other chemical equipment, as an inert diluent for chemicals, and in the float glass process to prevent oxidation of the molten tin (p. 370). It is also used as a blanketing gas in the electronics industry, in the packaging of processed foods and pharmaceuticals, and to pressurize electric cables, telephone wires, and inflatable rubber tyres, etc. 

Ausfuhrungs-gang, m. excretory duct, -mittel, n. purgative, -rohr, n., -rfihre, /. discharge pipe or tube, outlet pipe or tube. 

The furnace blower or boiler circulator pump starts up to send heated room air or hot water through the ducts or hot water pipes to the steam radiators, or hot water baseboard units, or individual room air registers located throughout the house. When the thermostat is satisfied that the room temperature has reached the set point, the burner shuts off. In furnaces, the blov er continues to run a few seconds until the air temperature drops to about 90° F, then the blower also shuts off. The furnace blower may come on again before the next burner start-up to purge heat out of the furnace, particularly if the fan has a low turn-on set point. The cycle... 

For pipework the purge volume may be taken as 1.5 times the pipework volume. For diaphragm meters the purge volume may be taken as 5 revolutions of the meter. For other meters the purge volume may be taken as 1.5 times the volume of a length of pipe equal to a flange-to-flange dimension of the meter. 

Slug purging Slug purging is appropriate only for long pipe runs. It should not be used to purge installations with branches unless each one can be (and is) valved off and purged separately. 

Purge points shall be fitted at section isolation valves, at the end of pipe runs and at other suitable positions to facilitate the correct purging of pipes. Pressure test points should be fitted at the outlet of each section-isolating valve. 

Valves V29 and V32 and the associated pipes contain leftovers of HCHO and must be purged with H2SO4 before the other chemical. 

It may be recalled that in the initial analysis sulfuric acid was used as a purge species. It is obvious that this is not possible anymore since one of the dangerous components, namely formaldehyde, cannot be brought into contact with sulfuric acid. Thus the computer must generate new piping and source and sink structure to allow the computer to find a purge route. 

After the silica flour or soil mixture has set, add a layer of silica sand as a filter pack, then fill the remainder of the borehole with bentonite or a grout seal (Figure 5). Access lines may be run from the lysimeter reservoir through a protective PVC riser pipe to the land surface. A locking protective casing should be used to secure the abovegrade lysimeter components. If the lysimeter is used immediately after installation, it is necessary to purge any water used to prepare the siiica flour or soil slurry. Remove at least the water volume equivalent to approximately one third of that used to make slurry. 

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