| 摘要 |
<p>An oval trap is welded on to the outside of sharp bend in a pipe, where unscrewing of a handwheel permits the external cross-stay, bolt and oval closure to be rotated and withdrawn through the hole, for access to the piping in both directions. The trap surround, preferably made in cast or stainless steel, is welded by inner and outer seams to the pipe bend and contains a similar closing piece mated against a round-section sealing ring of plastics or soft metal. To guard against wear by corrosive or abrasive agents the closure plate must be replaceable; a safety chain is attached to the parts to prevent loss in the piping. The closure is useful in beer and paper pulp conduits where rodding may be required to prevent blockage by suspended solids.</p> |
