COPOLYMER FLAP GATES

Plasti-Fab flap gates act as a check valve by allowing flow to pass in one direction only. Any seating head will be held back, and unseating heads will pass. Like all Plasti-Fab products, Copolymer flap gates are corrosion resistant and long lasting. Key features include: Very low leakage rates, Rugged construction, Light weight when compared to cast iron or steel gates, Lower discharge head requirements, and Virtually no maintenance.

Plasti-Fab manufactures three distinct styles of flap gate.

Type I flap gates have a rigid door with a flexible neoprene hinge/seal arrangement. This is generally a Copolymer gate with a circular or rectangular body. Type I flap gates range in size from 4 inches to 36 inches.

Type II flap gates also have a rigid door, but use a stainless steel hinge mechanism to support the door. These gates will generally be used to close off larger openings and can be circular or rectangular. Double hinges are often required to help center and support the gate.

Type III flap gate has a flexible cover or door, and is generally a larger tide or back flow control gate. This style of gate will most often be fabricated of stainless steel, will be square or rectangular, and can have a single or multiple covers. Type Ill gates are wall mounted and are available up to 8 feet square.

GATE BODY: The Copolymer flap gate has a reinforced composite (FRP) body. Standard molds exist for all common pipe sizes from 4” through 60” diameter. Rectangular Copolymer gates range in size from 24” to 60”. Stainless steel gate bodies will be of T-304 or T-316 stainless steel as required by the application. These gates are typically square or rectangular and are available from 24” to 120”.

Depending on the style, size and application, flap gates will be bolted directly to a wall or bulkhead, flange mounted to a pipe, or clamped to the exposed end of a pipe.

COVER OR FLAP: The Type I hinge/seal assembly is a one piece cover that mounts directly to the gate body and will never need adjustment. It is perfectly aligned with the seating surface of the gate to produce a tight seal every time. Covers from 4” to 21” diameter are molded neoprene with an internal steel reinforcing disc. Larger diameter and rectangular covers are of molded neoprene and will have an FRP cover to provide the necessary structural support. Reinforcing belts or plys are vulcanized into the flap to prevent sagging.

The Type II gate cover uses a single or double stainless steel hinge, and is preferred by some engineers because of its more traditional look. The stainless steel hinge bolts directly to an FRP cover with a neoprene facing seal. Half inch diameter hinge pins with nylon sleeves permit the cover to rotate and seal tightly against the gate seat.

Type Ill flexible covers clamp directly to the gate body and frequently require additional support to maintain a flat seat. Generally steel reinforcing bars are molded into the neoprene flap, or external horizontal stiffeners are affixed to the cover. Sometimes vertical stainless steel support angles can be built into the clear opening of the gate body to provide the needed support.

LOCATION: Flap gates are most commonly found at the end of a pipe line for back flow control, or to seal out pests and provide vector control. They are seen at many river out falls, in tidal and marshy areas, and around lakes or reservoirs with fluctuating water levels. Water and wastewater treatment plants are beginning to use more of these gates.

Copolymer & Stainless Steel Flap Gates

                        Type I                                     Type II                                    Type Ill

Gate Cover      Rigid                                       Rigid                                       Flexible

Hinge              Flexible hinge/seal                   Stainless Steel                         Flexible

Gate Body
Typical            4” to 36”                                 24” to 72”                              36” to 96”
size range                                                       

Material           Copolymer                              Copolymer & S/S                    Stainless Steel

Shape              Round                                     Round or                                 Rectangular
                                                                        Rectangular

Mounting        Wall, Flange or                        Wall or Flange                         Wall mounted
Compression Ring

WHY BUY PLASTI-FAB?

1. High corrosion resistance. Great for sea water and coastal areas or other harsh environments, especially when used with the neoprene seal/hinge.
2. Excellent leakage performance.
3. Light weight fiberglass.
4. Low head loss.
5. Little or no maintenance.

Electrical components and considerations

1. The shelter NEMA ratings most often apply to the smaller instrument and chlorinator shelters. This is intentional because the smaller enclosures are designed and built to resemble a walk-in electrical cabinet. NEMA 3R is our standard and refers to a shelter that will not allow water penetration under heavy storm conditions. Also any internal electrical equipment is isolated from outside contact through any wall openings. NEMA 4X indicates that the shelter is water tight, dust tight, and corrosion resistant, and that the shelter will stay dry inside even when sprayed at close range by a fire hose. For all practical purposes this means that the shelter can not have any exterior vents or openings.
2. An Exhaust Fan is typically used in instrument and sampling shelters. This is mounted high on the shelter wall and is either switch or thermostatically controlled.
3. For shelters that house chlorine and other heavy corrosive gases or chemicals Plasti-Fab will install a Purge Fan near the top of one wall and locate the vent on the opposite wall near the floor. A Purge fan draws fresh air from outside the enclosure and pushes the contaminated air that has settled near the floor out through the low vent. This method assures that the fan and its critical electrical wiring is not exposed to premature failure due to excessive contact with the corrosive gases.
4. Plasti-Fab is also experienced with Class I, Division I & II Explosion Proof requirements, and has supplied a number of shelters meeting these codes.
5. Standard electrical packages normally include a NEMA rated service panel, light & switch, heater with thermostat, fan, convenience outlet and wiring. Other components available include: air conditioners, warning lights, alarms, junction boxes, etc.

CAPABILITY

Plasti-Fab has the specialized capability to take standard shelter units and add customized features to satisfy a wide variety of site and application requirements. Wall height from 7 ft. to 12 ft. are available. Roof style can be flat, gabled or sloping and can be fitted with lift-off panels or completely detachable for crane access to pumps and heavy equipment. Windows and lifting eyes are common accessories. Larger shelters up to 20 feet square can be shipped as knock-down units for quick assembly at the job-site.

Fiberglass shelters and covers can be acoustically lined and tested to limit noise of pumps. They can also be insulated to any degree necessary. Shelters can be made with fire retardant resins, fitted with fire suppression systems, detectors, alarms, shelves and explosion-proof electrical features. Plasti-Fab can add any desired accessory and meet any design requirements.

 

Fiberglass shelters are light weight and easy to transport, and can be skid mounted to increase their mobility. Plasti-Fab shelters are currently being used to house: liquid and dry chlorine systems; chemical feed/storage; medical & biohazardous wastes; instrumentation and water sampling equipment; air quality monitoring equipment; communication systems and equipment; telemetry systems; blowers, generators & pump enclosures; on piers, docks & offshore stations.

If corrosion resistance and long service life are important, expect to see a Plasti-Fab fiberglass shelter handling the job.