E-mail jerry@freeflowinc.com Phone 800-933-4818 or 402-332-4818 Fax 402-332-3036
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Free Flow Metering Manholes Free Flow prefabricated fiberglass flow metering manholes are designed to provide an accurate flow metering station with minimal on site installation time. Typical uses for the metering manholes include: Sanitary sewers Metering manholes are available with a variety of different primary flow elements including: Parshall flumes Application Criteria: The upstream & downstream conditions for use of a particular type of flume or weir in a manhole must meet the recommended conditions for that type of flume element. Details of Construction: Standard materials of construction are fiberglass reinforced polyester with a polyester gel-coat finish on all surfaces. For additional strength, improved chemical resistance, or high temperature resistance, vinyl ester gel-coat and resin construction can be supplied. All metal parts and fasteners used in the construction of the flume are stainless steel. Upstream and downstream end connections to almost any type of pipe can be supplied. Pipe stubs with flexible neoprene couplings and stainless steel band clamps provide a quick connection to most pipes. Flat face fiberglass pipe flanges with standard 125# or 150# flange dimensions are also available. Upstream transitions are designed to provide proper flow conditioning at the flume's inlet, assuming reasonable pipe slope upstream of the metering manhole. Head loss and any required fall downstream of the flume, for a free discharge, should be accounted for by specifying the appropriate elevation difference between the upstream and downstream pipe stubs. Manholes intended for installation in non-traffic areas (such as parking lots barricaded to prevent vehicles from driving over manhole, or on grass lawn areas) can have a hinged lid which allows the full area of the manhole to be opened providing excellent light and access. Manholes intended for traffic areas must have the dome top for use with a standard iron ring and manhole lid to have H-20 traffic load rating. 4 ft. or 5 ft. diameter manhole barrels are available for non-traffic areas. For H-20 traffic areas the 4 ft. diameter manhole must be used. Installation: Lifting eyes, permanently attached to the manhole exterior, are provided to lift and position the manhole during installation. Metering manholes require a concrete slab under the full length of the manhole and flume. The slab must be of sufficient thickness and weight to resist the buoyant forces resulting from a high water table being present at the manhole during operation. Manholes are provided with anchor points which are to be secured to the slab by bolting down to L bolts, cast into the concrete slab. The area surrounding the manhole is to be backfilled with 3/8" pea gravel. Backfill must not have concrete, rocks, or any debris over 1 inch in size. Standard Features: Watertight one piece construction Standard Features of Hinged Lid Model: Stainless steel hinge, hasp and handle Standard Features of Domed Top Model: 22-1/2” diameter opening for use with iron ring and manhole cover (ring &
cover not supplied by Free Flow) |
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