WEIR GATES
Model GH-60 Aluminum Downward Opening Weir Gates
Similar design also available in Stainless Steel: Model GH-66
This section covers Aluminum Weir Gates and Operators. The equipment provided under this section shall be fabricated, assembled, erected, and placed in proper operating condition in full conformity with the drawings, specifications, engineering data, instructions and recommendations of the equipment manufacturer.
Gates and operators shall be supplied with all the necessary parts and accessories indicated on the drawings, specified, or otherwise required for a complete, properly operating installation, and shall be the latest standard product of a manufacturer regularly engaged in the production of fabricated gates.
Approved Manufacturers
This section covers Aluminum Weir Gates and Operators. The equipment provided under this section shall be fabricated, assembled, erected, and placed in proper operating condition in full conformity with the drawings, specifications, engineering data, instructions and recommendations of the equipment manufacturer.
Gates and operators shall be supplied with all the necessary parts and accessories indicated on the drawings, specified, or otherwise required for a complete, properly operating installation, and shall be the latest standard product of a manufacturer regularly engaged in the production of fabricated gates.
Approved Manufacturers
Weir gates supplied under this section shall be as manufactured by Golden Harvest Inc. or engineer approved equal.
Governing Standards
Except as modified or supplemented herein, all gates and operators shall conform to the applicable requirements of AWWA standards.
Quality Assurance
The manufacturer shall have 5 years experience in the production of substantially similar equipment, and shall show evidence of satisfactory operation in at least 10 installations. The manufacturerÕs shop welds, welding procedures and welders shall be qualified and certified in accordance with the requirement of the latest edition of AWS Sections D1.1, 1.2 and 1.6.
The fully assembled gates shall be shop inspected, tested for operation and leakage, and adjusted before shipping. There shall be no assembling or adjusting on the job sites other than for the lifting mechanism.
Submittals
1. The manufacturer shall submit for approval by the purchaser, drawings showing the principal dimensions, general construction and materials used in the gate and lift mechanism.
2. The manufacturer shall submit for approval by the purchaser, complete engineering design calculations in compliance with AWWA standards latest edition.
Performance
Leakage: Gates shall be substantially watertight under the design head conditions. Under the design seating head, the leakage shall not exceed 0.1 US gallons per minute per foot of seating perimeter. Under the design unseating head, the leakage shall not exceed 0.1 US gallons per minute per foot of perimeter.
Materials and Construction
General Design
Gates shall be either self-contained or non self-contained of the rising stem or non-rising configuration as indicated on the gate schedule.
All parts of the gate shall have a minimum thickness of 1/4 inch.
Frame
The gate frame shall be extruded aluminum weighing not less then 4-1/4 pounds per foot. The guide grooves in which the head guide angle travel shall contain ultra high molecular weight polyethylene bearing bars in dovetail slots.
The frame configuration shall be of the flush-bottom type and shall allow the replacement of the top and side seals without removing the gate frame from the wall or wall thimble.
Slide
The slide shall consist of aluminum plate reinforced with ÒUÓ shaped aluminum extrusion welded to the plate to limit its deflection to 1/720 of the gate's span under the design head.
Guides and Seals
The guide groves shall contain UHMW bearing bars in dovetail slots and shall be of such length as to retain and support at least two thirds (2/3) of the vertical height of the slide in the fully open position.
Side and invert seals shall be frame mounted. Seals shall be resilient neoprene of the J-bulb type attached with a stainless steel retainer bar. Seals shall be fully adjustable.
When required for shutoff purposes a neoprene top seal shall be mounted to the top spigot member.
Yoke and Pedestal.
Self-contained gates shall be provided with a yoke made of structural members or formed plates. The maximum deflection of the yoke shall be 1/360 of the gate's span.
Non-self contained gates shall be provided with pedestal mounted lifts. Pedestal shall be provided with shop coating.
Lifting Assemblies
The operating stem shall be of stainless steel designed to transmit in compression at least 2 times the rated output of the operating manual mechanism with a 40 lb effort on the crank or handwheel.
Gates having a width equal to or greater than two times their height shall be provided with two geared lifting mechanisms interconnected by a tandem shaft.
The stem shall have a slenderness ratio (L/R) less than 200. The threaded portion of the stem shall have Acme type cold rolled threads with a maximum surface of 16 micro-inches.
Stem lengths requiring more than one piece shall be coupled or pinned to an extension tube.
Stem Guides
Stem guides shall be fabricated from stainless steel. Stem guides shall be equipped with a UHMWPE bushing. Guides shall be adjustable and spaced in accordance with the manufacturerÕs recommendation. The L/R ratio shall not be greater than 200.
Stem Cover
Rising stem gates shall be provided with a clear polycarbonate stem cover. The stem cover shall have a cap and condensation vents and a clear mylar position indicating tape. The tape shall be field applied to the stem cover after the gate has been installed and positioned.
Lifting Mechanism
Operators of the types listed in the schedule shall be provided by the gate manufacturer. Each manual operator shall be designed to operate the gate under the maximum specified seating and unseating heads by using a maximum effort of 40 lb on the crank or handwheel, and shall be able to withstand, without damage, an effort of 80 lb.
Gearboxes shall be provided when required to maintain the operating force below 40 lb. All bearings and gears shall be totally enclosed in a weather tight housing. Geared operators shall be furnished with a threaded bronze lift nut to engage the threaded portion of the stem. The pinion shaft of crank-operated mechanisms shall be constructed of steel and supported by roller or needle bearings. The operating shaft shall be fitted with a 2 inch square operating nut and removable crank. The crank shall be fitted with a corrosion-resistant rotating handle. The maximum crank radius shall be 15 inches and the maximum handwheel diameter shall be 24 inches.
Materials
| Part | Material |
|---|---|
| Frame, Yoke, Slide, Stem extension | Aluminum 6061-T-6 ASTM B-209, ASTM B-211 |
| Side and Top seals | Neoprene ASTM D-2000 |
| Bearing bars, Guides, Stem guide liner | Ultra High Molecular Weight Polyethylene ASTM D4020 |
| Bottom seal | Neoprene ASTM D-2000 |
| Threaded stem, Stem guides, Hand crank | Stainless steel ASTM A-276, Type 304 or 304L |
| Fasteners | Stainless steel Type 304 or 304L |
| Pedestal / Wall Bracket | Cast Iron ASTM A126, class B or Mild Steel A36/A36M |
| Stem cover | Polycarbonate ASTM A-707 |
| Lift and stop nut | Manganeze bronze , ASTM B584, UNS-C86500 |