SECTION 13224 FILTER SURFACE AGITATOR SYSTEM

SECTION 13224
FILTER SURFACE AGITATOR SYSTEM


PART 1 - GENERAL

1.1     WORK INCLUDED

A.   Furnish and install as described herein and as shown on the Drawings, a surface wash system for each filter including all materials, equipment and labor required for a complete installation in each filter.

1.2     RELATED WORK

A.   Section 02610 - Water Pipe and Fittings. B.   Section 13223 - Filter Disinfection.
1.3     REFERENCES

A.   ANSI Applicable Specification. B.   ASTM A312.
C.   ASTM A774.

1.4     EXPERIENCE

A.   The manufacturer of the surface agitator system shall have an experience record of similar proven filter designs and installations of at least five (5) years.


PART 2 -  PRODUCTS

2.1     GENERAL

A.   The surface agitators for each filter (new) shall be self-propelled rotary type consisting of a stationary center bearing housing, rotating distributor arm and water dispersion nozzles. The system includes the surface agitators, header system, supports and downpipe stabilizers. The system shall be as furnished by The F. B. Leopold Company, Tetra Technologies, Inc., or approved equal.

2.2     CENTER BEARING

A.   The center bearing assembly shall be suitable for connection to the surface wash piping. The center bearing assembly shall be constructed of a ball bearing type central housing stabilized for vertical and horizontal bearing pressure, containing a stainless steel ball bearing assembly which is packed in grease and sealed by means of a non-adjustable, self-compensating, Buna-N O-ring seals. The other parts of the center bearing shall be made from non-metallic materials such as Delrin and shall provide a dielectric interface between the drop pipe and the distributor arm.

2.3     DISTRIBUTOR ARM

A.   The rotating distributor arm shall be made of a unitized weld assembly Schedule 5, Type 304 stainless steel. A screwed or slip type joint shall not be acceptable where the distributor arm intersects the vertical centerline of the drop pipe. The connection between the distributor arm and the dispersion nozzles shall be of the snap fit type only. The arm shall extend outward from the vertical centerline of the bearing in a horizontal manner and then bend 90 degrees in the horizontal plane. A stainless steel end cap shall be located at the end of each arm and contain four additional nozzles.
2.4     DISPERSION NOZZLES

A.   Dispersion nozzles shall be spaced to effectively distribute water to the filter surface and shall be set 15 degrees downward from the horizontal plane. Nozzle shall be easily replaced with common tools. The use of threads to attach the nozzle to the arm shall not be acceptable except at the end cap. Agitator nozzles shall be molded Delrin with 2- inch overall length with a f- inch hexagonal wrench flat provided. Nozzles shall be color coded by nozzle size. Nozzles
shall be designed to accommodate and retain a snap-on flexible synthetic rubber cap provided with a four-way cross cut opening which shall open under pressure and close automatically when pressure is turned off. The cap shall be a nominal 1-inch diameter and shall have an internal shoulder to snap into a groove of the nozzle.

2.5     HEADER SYSTEM

A.   The header piping and fittings for each filter shall be Schedule 5, Type 309 stainless steel with flanged joints. The pipe shall meet ASTM A312 and pipe fittings shall meet ASTM A774. The agitator piping system shall be shop tested at the operating pressures for this project prior to shipment.

B.   Downpipe connection shall be flanged with suitable dielectric insulation so that dissimilar metals are isolated. Dielectric insulators shall consist of filled nylon bolt sleeves and a full face flange gasket. All flange hardware shall be Type 18-8 stainless steel.

2.6     SUPPORTS AND DOWNPIPE STABILIZERS

A.   The header support brackets, angles, bolts and attachment hardware shall be stainless steel.
Structural members shall be 3/16 inches minimum thickness and "U" bolts shall be 3/8 inches minimum diameter.


PART 3 -  EXECUTION

3.1     INSTALLATION

A.   Installation of the filter surface agitator system shall be coordinated with other filter installation requirements as described elsewhere in the Specifications. The Contractor shall supply the system header for each filter with a dielectric insulator of suitable material.

B.   Disinfection of the filter surface agitator system shall be performed prior to being placed in service as required in Section 13223.

C.   The system shall be field tested by the manufacturer's representative. Certification of the test results shall be delivered in writing to the Engineer for acceptance prior to being placed in service.