FLOW MEASURING EQUIPMENT

supports shall be adjustable type with provision for firm anchorage. Where

support is from tank walls, welded steel brackets shall be provided with

anchor chair.

2.12

FLOW MEASURING EQUIPMENT

The effluent flow measuring equipment shall be V-notch weir and flowmeter.

2.12.1

V-Notch Weir

The V-notch weir measuring channel for measuring effluent of plant shall be

made of 6 mm 1/4 inch steel with a stainless steel or aluminum 1.05 rad 60

degree V-notch weir plate. The notch shall be cut with extreme accuracy

and care to maintain sharp upstream edges and exact cross section, the

downstream edge shall be beveled. The upstream face of the weir plate

shall be flat and smooth; any bolts or rivets used to fasten the plate

shall be countersunk flush with the plate. Bolt holes shall include

provision for adjustment of height and level. The bottom of the notch

shall be approximately 125 mm 5 inches above the floor of the channel and

the invert of the channel outlet. The invert of the inlet shall be at the

same elevation as the bottom of the V-notch. A 250 mm 10 inch long scale

for measuring the water depth upstream of the weir shall be provided and

securely fastened in the channel. Scale shall be stainless steel with

baked-on enamel. The channel shall be rectangular, and provided with a

baffle and 50 mm 2 inch drain and plug. Inlet and outlet connections shall

be ASME B16.1 200 mm, 862 kPa 8 inch, 125 lb. A flow chart of the 1.05 rad

60 degree V-notch weir shall be furnished, indicating flow in L/s thousand

gallons per day. Capacity of weir and channel shall be not less than

capacity of plant at peak flows.

2.12.2

Flow Meter

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NOTE: Delete "transmitting" when hypochlorinator is

specified. Hypochlorinator should be specified for

all plants 4.38 L/s 100,000 GPD capacity and below.

Chlorinator should be specified for all plants 6.57

L/s 150,000 GPD capacity and above. Between 4.38

L/s and 6.57 L/s 100,000 GPD and 150,000 GPD

capacity either is suitable. Selection should be

made on basis of existing station or base practices,

local availability, and comparative costs.

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NOTE: Delete reference either to recorder or to

recorder-totalizer-indicator. A recorder-totalizer-

indicator should be specified instead of a recorder

when it is necessary to keep records of total flow.

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NOTE: Delete last part of first sentence when

hypochlorinator is specified.

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Flow meter shall include in-stream float or float-and-cable mechanism for

differential measurement and a [transmitting] [recorder]

[recorder-totalizer-indicator] for local read-out [and for transmission to

SECTION 11375N

Page 63