Wiper plug

Figure 4-389 gives a series of schematics that show how the spacer and cement slurry displace drilling mud in the well. Two wiper plugs are usually used to separate the spacer and the cement slurry from the drilling mud in the well. The cementing head has two retainer valves that hold the two flexible rubber wiper plugs with two separate plug-release pins (see Figure 4-389a). When the spacer and the cement slurry are to be pumped to the inside of the casing...

When the bottom wiper plug reaches the float collar there is a brief sharp rise in pump pressure. The pump pressure increase breaks the diaphragm in the lower wiper plug. Once the diaphragm is broken the spacer and the cement slurry flow through the float collar into the final joint or two of the casing... 

A wiper plug may be accommodated with special equipment [161]. 

Two-plug method is a rather new method and requires the use of the telltale catcher sub (Dowell Schlumberger) to set a cement plug in a well at a rather precise location with minimum contamination. The tell-tale catcher sub is made up to the lower end of a drillpipe string. The sub also has an aluminum tail pipe, a bottom wiper plug (which carries a dart) and a top wiper plug. The sub on the drillpipe is lowered to the depth desired for... 

Pope slotted wiper blades promote plug flow with little back mixing. This minimizes dwell time distribution, ensuring that material flowing through the system has a uniform exposure to process conditions. 

PP/EPDM TPV for automotive applications include rack and pinion bellows, air ducts, underhood tubing and connector, underhood hose, plugs, bumpers, grommets, prop rod shaft cover, radiator air deflector, air bag door covers and skins, grips, seals, mats and cupholders, windshield wiper motor cover, fuel line hose, suspension bellows, and weatherseals. EPDM/PP TPV was also used for construction such as door sweep, expansion joints, and window and door seals. Electronic applications include scroll wheel, printer roller, scanner lid, grip, access panel door, speaker surrounds, and holders and bumpers. Also, TPVs are widely used in business machines, power tools, motor mounts, and many other fields. 

Engineering Uses PBT often preferred, but PET used for transformers, bobbins, industrial plugs and sockets, heater housings for vehicles, coffee machines and toasters, fuel filler flaps, windscreen wiper arms, ignition coil housings, sun-roof frames, pump housings, electronic packaging. 

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