Flexible Cover

An important variant of the in situ process is foaming within a flexible cover. As the foam expands, it forces the cover outwards to conform to the interior shape pf a mold. We make extensive use of this process to make seat cushions for automobiles and office furniture. 

In cell houses, cracks can be visually seen on the upper neoprene surface of the flexible covers which are subjected to stress at a temperature of 80°C, during eighteen to twenty four months of operation, necessitating mandatory replacement of the covers. Ozone reacts with double bonds so rapidly that it has no chance to diffuse into the rubber and therefore all action is at the surface. Thus it implies surface protective agents are most useful against ozone attack. For example, waxes that bloom to the surface of rubber to form an inert film are used effectively for static protection. 

Bag molding (blanket molding)—A method of molding or bonding involving the application of fluid pressure, usually by means of air, steam, water, or vacuum, to a flexible cover which, sometimes in conjunction with the rigid die, completely encloses the material to be bonded. 

Adjustment of the width of a tow band is achieved with a variable bow roller (e.g. a Mount Hope or Wittier roller). When a bowed roller rotates, the flexible covering of the roller expands and contracts as it passes from the inside to the outside of the roller. During the expansion of the covering, a point on the roller surface, viewed perpendicular to the plane of the roller bow, will follow a radial line drawn through the center of curvature of roller bow. A tow free to move along the roller surface will tend to follow such a radial line. Thus, if the tow width a at roller X is known (Figure 11.15c) and it is required to spread the sheet to a width b using an adjustable bowed roller T at a distance c from roller X, it... 

In some recent publications from Korea custom made flexible covered metallic stents were advocated for gastroduodenal as well as colonic obstruction. Modified Z-stents were covered with a polyurethane membrane and stent shapes were further changed to improve flexibility and fixation (Choo et al. 1998 Jung et al. 2000 Park et al. 1999, 2001 Lee et al. 2001). 

Lee JM, Han YM, Lee SY (2001) Palliation of postoperative gastrointestinal anastomotic malignant structures with flexible covered metallic stents preliminary results. Cardiovasc Intervent Radiol 24 25-30 Lobato RF, Pinto I, Paul L (1999a) Self-expanding prostheses as a palliative method in treating advanced colorectal cancer. Int Surg 84 159-162... 

Joubaud L, Achim V, Trochu E Numerical simulation of resin infusion and reinforcement consolidation under flexible cover. Polymer Composites, 2005 26(4) 417-427. DOI http //dx.doi.org/10.1002/pc.20069. 

The plant should be equipped with radiation shielding materials of different types for temporary use in special jobs. Examples of such shielding materials are lead blankets (lead wool in flexible covers), sheets and bricks of lead, sheets of transparent perspex and blocks of concrete. 

Where protective flexible coverings are installed they are installed by a competent person to ensure that appropriate overlapping is achieved >- Electrical supplies may be intrinsically safe dependent upon the hot work processes being undertaken, e.g. the use of LPG... 

EDAM Enclosed dry air method (method of storage of mihtaiy equipment using flexible covers and dehumidifiers). 

---