Model GH-27 Tapered-Wedge Aluminum Gates

Similar design also available in Stainless Steel: Model GH-29

This section covers Wedged Aluminum 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
Gates supplied under this section shall be Model GH-27 Tapered-Wedge Aluminum Gates 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-C561 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 manufacturer’s 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.

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.

Leakage: Sluice gates shall be substantially watertight under the design head conditions. Under the design seating head, the leakage shall not exceed 0.005 US gallons per minute per foot of seating perimeter. Under the design unseating head, leakage shall not exceed 0.01 US gallons per minute per foot of perimeter.

General Design

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 3/4 inch.

The gate frame shall be aluminum and designed for maximum rigidity. 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.

The slide shall consist of aluminum plate reinforced with “U” shaped aluminum extrusion welded to the plate to limit its deflection to 1/720 of the gate's span under the design head.

The head guide angles shall be attached to the slide in such a way to place the slide in an angle corresponding to the seating surface of the spigot.

Guides and Seals
The guides shall be provided with ultra high molecular weight polyethylene seats on both sides of the slide 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. Guide frame shall not weigh less than 13 lbs. per foot.

The seating face of the frame shall be oriented at an angle to the plane of the mounting flange to effect a wedging action upon closure.

Side and top seals shall be frame mounted. Seals shall be EDPM or neoprene D-seal with a stainless steel retainer bar and shall be fully adjustable.

The flush bottom resilient neoprene seal shall be mounted to bottom of disc and seal against the invert portion of the frame. Frame mounted invert seals will not be considered.

Yoke and Pedestal
The yoke, to support the operating bench stand, shall be formed by two structural members welded at the top of the guides to provide a one piece rigid frame.

Self-contained gates shall be provided with a yoke to support the operating bench stand. The yoke shall be formed by two structural members welded at the top of the guides to provide a one piece rigid frame. 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 cast iron or mild steel and provided with shop coating.

Lifting Assemblies

Stem and Couplings
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.

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.

Where a hydraulic, pneumatic or electric operator is used, the stem design force shall not be less than 1.25 times the output thrust of the hydraulic or pneumatic cylinder with a pressure equal to the maximum working pressure of the supply, or 1.25 times the output thrust of the electric motor in the stalled condition.

Stems in more than one piece shall be joined together by solid couplings.

Gates having a width equal to or greater than two times their height shall be provided with two lifting mechanisms connected by a tandem shaft.

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 manufacturer’s 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. Operator housing shall be cast steel or cast iron. The pinion shaft of crank-operated mechanisms shall be supported by roller 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.