Conical Type

Conical Basket Type Temporary Strainer

Conical Type Strainers are available in two basic shapes appropriately named a “Witch-Hat” type and a “Top Hat” type. The Witch-Hat type is shaped as a pointed cone, whilst the Top-Hat type has a flat top and in comparison is generally much shorter in length and, therefore, generally suited for pipework systems where only small clearances are available. Like the flat disc type, conical type strainers are designed to be sandwiched between a suitable flanged joint within the pipeline. They are available to suit a variety of flange facings including:- flat, raised face, ring joint, tongue and groove.

Each nominal size is available in two standard lengths, a “short” series and a “long” series. The “short” series (BHL) incorporates an open free area of 200% of the pipe bore area. Specials can also be provided to incorporate even larger open free areas upon request. The flow direction can either be “in to out” or “out to in”, but is normally “in to out” so that the contaminant is retained within the strainer.

Fine straining and filtering can also be achieved by incorporating mesh inlays (in-to-out flow direction) or outlays (out-to-in flow direction) to the units, however, this is not a good practice nor recommended because in adding a mesh inlay or outlay the open free area is radically reduced which increases operating pressure differentials and reduces operating service life.

Advantages

• Larger filtration areas than disc type, provides higher flowrates
• Lower pressure differentials than disc type
• Easy to clean
• Retains contaminant
• Low capital cost

Disadvantages

• Restricted access to the unit once installed into the pipeline
• Installation requires a spool piece to be built into the pipeline