Pipe jointing

Results of own stress measurements in the pipe joints zone applied in high power, have been shown in Fig 5 and 6. 

Other Types of Piping Joints Packed-gland joints (Fig. 10-135) require no special end preparation of pipe but do reqmre careful control of the diameter of the pipe. Thus the suppher of the pipe shoiild be notified when packed-gland joints are to be used. Cast- and ductile-iron pipe, fittings, and valves are available with the bell cast on one or... 

Cooling tower Threaded pipe joints Bolts, nuts, washers Partially exfoliated coatings Lap joints in sheet metal Between bushings and shafts on pumps Pump gaskets... 

Flange face sheet gaskets at pipe joints. 

Deliberate stray current drainage was installed at a subrectifier in Germany as early as 1895 during the electrification of the Aachen tramway. The effective protection extended over a relatively small field since the comparatively large resistance of the pipe Joints did not permit a greater extension of protection. 

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. 

Maintain supplies of neutralizing chemicals, e.g. soda ash Provide hosing-down facilities where appropriate Minimize joints, particularly drain and sample points, valves/pipe joints, flanges over access ways... 

Irregular Plant maloperation (e.g. unauthorized venting ) Plant failure - spillages, pipe joint failures Start-up/shutdown Dismantling/demolition Unauthorized waste incineration (rubbish burning) Fires ... 

Infiltration The seepage of groundwater into a sewer system, including service connections. Seepage frequently occurs through defective or cracked pipes, pipe joints, connections or manhole walls. 

A passive design must include all hardware elements of the system. Little is gained if containment is lost when pipes, joints, or instruments fail due to overpressure. 

The leaks that lead to explosions in compressor houses are often not from a compressor but from other equipment, such as pipe joints. One such leak occurred because a spiral-wound gasket had been replaced by a compressed asbestos fiber one, probably as temporary measure, seven years earlier. Once installed, it was replaced by a similar one during subsequent maintenance [30]. 

In addition, they are usually constructed without isolation valves on the fuel supply lines. As a result the final connection in the pipework cannot be leak-tested. In practice, it is tested as far as possible at the manufacturer s works but often not leak-tested on-site. Reference 32 reviews the fuel leaks that have occurred, including a major explosion at a CCGT plant in England in 1996 due to the explosion of a leak of naphtha from a pipe joint. One man was seriously injured, and a 600-m chamber was lifted off its foundations. The reference also reviews the precautions that should be taken. They include. selecting a site where noise reduction is not required or can be achieved w ithout enclosure. If enclosure is essential, then a high ventilation rate is needed it is often designed to keep the turbine cool and is far too low to disperse gas leaks. Care must be taken to avoid stagnant pockets. 

With the 3 in. pipe rams closed on the 3 in. drill pipe, open rotating head and pull the rotary bushings. While stripping with the pipe rams, raise the liner string (with the 3 in. drill pipe) until the 4 in. stripper rubber and the drill pipe joint it is on are above the rotary table. Replace the rotary table bushings and, using the rotary slips, remove this drill pipe Joint with the 4 in. stripper rubber (the 4 in. stripper rubber can be removed from this joint later). 

Pick up a joint of 3 in. drill pipe with a 3 in. stripper rubber attached. Make up this 3 in. drill pipe joint to the liner string s upper drill pipe joint being held in the rotary slips. 

The most fundamental difference found between onshore and offshore drilling occurs when the wellhead is located at the seafloor. This configuration makes communication with the well more complex. A marine riser provides communication and circulation capability between the surface and the seafloor, and is used at some point during most offshore drilling. The riser consists of large-diameter (17-20) in.) steel pipe joints of approximately 50-ft lengths, with quick-connect couplings. The riser can be connected at the seafloor to a wellhead or to a subsea blowout preventer stack. A diverter system is usually attached at the... 

Another material used on pipe threads is sealant tape. This tape, which is made of Teflon, provides an effective means of sealing pipe connections and eliminates the necessity of torquing connections to excessively high values in order to prevent leaks. It also provides for ease of maintenance whenever it is necessary to disconnect pipe joints. The tape is applied over the male threads, leaving the first thread exposed. After the tape is pressed firmly against the threads, the joint is connected. 

Although iron pipes suffer from the same corrosion risk as steel pipelines, associated with the generation of a galvanic cell with a small anode and a large cathode, the risk is mitigated for iron pipelines because the electrical continuity is broken at every pipe joint. For this reason long-line currents are uncommon in iron lines and cathodic protection is rarely necessary. It also accounts for the ability to protect iron lines by the application of nonadherent polyethylene sleeving . 

The networks that interconnect various process units and vessels to the discharge zones or flares occur widely in refineries and chemical plants. Figure 11 shows a typical configuration in which the root represents the flare, the terminal vertices represent the relief valves, and the edge (each labeled with an arabic numeral) represents a pipe section between two physical junctions (valves, flare, or pipe joints). The configuration of such a network is dictated by the layout of the process unit. In this discussion both the lengths of the pipe sections and the interconnections will be treated as specified variables. 

Shielding and backing gas used for welding pipe joints shall be per ASME BPV Code Section II, Part C, specification SFA-5.32. 

Piping joints shall be selected to suit the piping material, with consideration of joint tightness and mechanical strength under expected service and test conditions of pressure, temperature, and external loading. Layout of piping should, insofar as possible, minimize stress on joints, giving special consideration to stresses due to thermal expansion and operation of valves (particularly a valve at a free end). 

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