Slide rings

Taylor s bag-fil t T—Fig.556—consists of a number of cotton hags about two feet in length and a foot in diameter when fully extended. Inte their narrow months the nozzles of the lubes pass which deliver the sirup. The bags aro fastened on the nozzles by means of a sliding ring. Bach bag is inclosed in a cylindrical one of canvass about four inches in diameter, tho object of which is to prevent the swelling out of the interior cotton filter. In such a filter of course the interior bog is much folded nor can it in this state present the same amount of filtering surface as it. would were it fully inflated. It may indeed be questioned whether... 

Use is made of screw tip valves, popularly called non-return valve, ball check valve, or sliding ring valve. They are used in reciprocating injection and injection blow molding machines (IMM and IBMM) to control the melt flow in one direction (Chapter 4). There is also the smearhead for IMM, IBMM, and extruder. Back flow will not occur... 

Karino T, Okumura Y, Ito K, Shibayama M, (2004) SANS studies on spatial inhomogeneities of slide-ring gels. Mactomolecules 37 6177-6182... 

Karino T, Okumura Y, Zhao C, Kataoka T, Ito K, Shibayama M. (2005) SANS studies on deformation mechanism of slide-ring gel. Macromolecules 38 6161-6167 Haraguchi K, Takehisa T. (2002) Nanocomposite hydrogels a unique organic-inorganic network structure with extraordinary mechanical, optical, and swel I ing/de-swelling properties. Adv Mater 10 1120-1124... 

Figure 3.3. Synthesis scheme of azobenzene-containing slide-ring gels. Sakai et al., 2007.

Figure 3.4. Swelling behavior of slide-ring gels in DMSO upon alternate irradia-tion of UV and visible light. D and Do are diameters of the gel and inner diameter of mold capillary, respectively. Source Sakai et al., 2007.

Sakai T, Murayama H, Nagano S, Takeoka Y, Kidowaki M, Ito K, Seki T. 2007. Photoresponsive slide ring gel. Adv Mater 19 2023 2025. 

Alumina is the most important oxidic abrasion-resistant material. Metal carbides are in some ways superior to oxides with respect to hardness and melting point, but they are much more brittle than the oxides and are only used in isolated instances as wearing bodies. Silicon carbide is characterized by its low thermal expansion and high thermal conductivity and has proved to be more resistant to thermal shock than oxides. Zirconia is tougher than alumina its modulus of elasticity is only about half as large, and it is comparable with that of steel. Zirconia is therefore very suitable for compound structures with steel. At present, the applications of ceramic sintered materials in chemical plant construction are slide rings, pump parts, and slide bearings. 

Figure 33. SSiC slide rings (ESK-Kempten, Germany).

The poor corrosion resistance of borides may be partially overcome in composites with SiC if the microstructure allows passive oxidation kinetics. In combination with SiC the borides retain their high electrical and thermal conductivity and thus suitable thermal shock resistance. SiC-TiB2 composites have been extensively developed for wear parts in machinery such as sliding rings, valves, valve seats, roller and ball bearings, plungers, and rocker arm pads. 

When the melt is forced into the mold, the plunger action could cause the melt to flow back into the screw flights. Generally, with heat-sensitive resins such as PVC and thermosets, a plain or smearhead screw tip is used. For other resins this is not adequate, and a number of different check valves are used. These devices work in the same manner as a check valve in a hydraulic system, allowing fluid to pass only in one direction. These check valves, which are basically a sliding ring or ball check design (Fig. 2-10) are supplied by many manufacturers. Here are some comparisons (100) ... 

Front discharge ball check less expensive than sliding ring valve. 

Side discharge type more expensive than sliding ring type. Greater pressure drop, creating more heat. 

Fig. 2-10. Basic screw tip designs, (a) Plain or smearhead (dissaembled). (b) Sliding ring (disassembled). (c) Ball check (assembled).

SiSiC and, especially SSiC, are displacing the chemically less-resistant tungsten carbide (hard metal) and the thermal-shock-sensitive aluminum oxide in modem mechanical seals, where they are used in the form of slide rings. The excellent wear resistance of sintered SiC, combined with its excellent chemical resistance and outstanding tribological characteristics, ensure that mechanical seals made from this material last longer, which in turn results in much-reduced maintenance and production costs for pump-dependent processes in the chemical industry [564]. 

Figure 5.60 Nonreturn valves (a) sliding ring/ (b) ball check valve/ and (c) smear tip. ...

Tribological tests were conducted in a sliding ring tribometre described elsewhere [35] with deioniz water as lubricant. During the experiment, the lubricant was applied with a pressure of 0.1 MPa between the friction couple. 

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