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Regulator Reconditioning Specifications

Part I - General

Scope

Work under this contract will entail the removal, restoration, modifications and reinstallation of three sewer regulators.   For this work the contractor shall engage the services of the original equipment manufacturer in order to provide a clear channel of responsibility through the entire process including the final certification of the restored regulator in place.   In accordance with the following requirements, some new components shall be furnished, other components reconditioned, and the operating design modified and the regulator reinstalled.   New regulator settings my be required.    Following cleaning of the regulator chambers by others, the manufacturer shall pre-inspect the chambers to record component positions and elevations, conditions, then remove the components, provide transport to the factory, prepare and submit drawings reflecting the changes, then recondition, return and reinstall the regulators.   Each shall be site tested and certified.   The performance of the equipment shall be guaranteed for period of one year following acceptance by the engineer.   The intent of this specification is to provide a factory-reconditioned regulator identical in performance to a new regulator and identical in construction to the other regulators in the system.

Experience

This costly equipment shall be reconditioned by the original equipment manufacturer.   The components shall be restored to original dimensions and tolerances where necessary to achieve the original working condition.

Special Equipment for Site Work

Contractor must perform all work in accordance with OSHA mandated Confined Space requirements.

Time

A total of _____ weeks shall be permitted for the completion of all of the operations specified including removals, shop work, furnishing required new components, reinstallation and certification. 

Part II - Specifics

The following components shall be removed and shop-reconditioned:  gate body, shutter gate and arms, outboard support, transmission wheels, pillow blocks and bearings, I-beams and clamps, wall plates, brackets and clamps, wall collar plate and stuffing box (if any), the float and float cover plate. 

The original Type 304 stainless steel components of float guides, float linkage assembly, shutterage linkage assembly, transmission shaft and attachment hardware shall be replaced as necessary with identical components except the replacement materials shall be Type 316 stainless steel.

The float shall be shop-reconditioned to include removal and disposal of the cover plate.   The interior is then checked for leaks and drilled, tapped and plugged where necessary.   Interior weights are checked and corrected supplemented to provide horizontal positioning of the float when suspended on its linkage.   The interior is then filled with an approved urethane foam.   A new cover plate designed for the modified float guides shall be furnished and installed with a new plate gasket.    Following these procedures, the exterior shall be sandblasted, primed and coated with the approved epoxy in accordance with the manufacturer's recommendations.

It is presumed that all of the major components of the regulator gate, gate body and float can be reconditioned.   In the event that any of these components must be entirely replaced, such replacements shall be castings which are identical in size, weight, material specifications and construction to the original components when new.   Fabrications regardless of the materials used shall not be permitted.

The reconditioned wall-mounted float mechanism shall be reinstalled using stainless steel anchors.   This mechanism must carry the full weight of the float even when the float chamber is dry, must duplicate the designed vertical travel of the float and include easily adjustable stops to limit the upwards and downwards travel of the float.   All new components except the stops shall be Type 316 stainless steel.

Wheels and bearings shall be removed from the transmission shaft.   Disassemble the bearings and pillow blocks, sandblast and epoxy coat the ferrous components, clean and lubricate the bearings and replace the bearings end seals.   If distorted, re-machine or replace the seal end plates.   Reassemble the pillow blocks with the bearings using new stainless steel bolts.   The transmission shaft shall be replaced with one of Type 316 stainless steel machined to the identical dimensions.

Transmission wheels or wheel sectors require sharp, clean tracks for the travel of the chain along the track with a minimum of friction or side drag.   If, after cleaning, the wheels or sectors are determined to be sound, with tracks that are clear, sharp as machined with no pitting or erosion, the wheels or wheel sectors may be retained. For cosmetic purposes, the external surfaces shall be sandblasted and epoxy coated.   Following cleaning, the wheels or wheel sectors shall be seen by the Engineer for his acceptance prior to further processing.   If the wheels or sectors do not meet the above criteria, these shall be replaced with new wheels or wheel sectors.  The new wheels or wheel sectors shall exactly match the original wheels for every dimension.   Except that wheel sectors may be substituted for full wheels in cases where the full wheel circumference will never by required.   They shall be cast iron, ASTM A-48 Class 35, and machined.   The diameters for the machining of the wheel tracks must be in exact accordance with the original design in order to the assembled regulator to accommodate the exact flows for which it was designed.

The transmission shall be reassembled using new brass keys and pins.

If required to be replaced, all components of the transmission linkages shall be identical sizes and lengths of welded link Type 316 stainless steel chain, stainless steel adjusting rods, buckles and carrying bars.

Flow stops shall be epoxy coated.   If required, new stainless steel anchors, nuts and washers shall be used for attachment in their new wall positions.

The gate body shall be sandblasted to bare, clean metal after first protecting the bronze seat faces.   Where these bronze seat facing bars are joined to the ferrous back surfaces, a careful inspection shall be made to determine that the original sealant is intact.  If cavities are detected, these shall be repaired with an approved sealant.   If necessary, the convex seating surface shall be re-machined and honed to the exact original contour.

Following the removal of the weight carrying bar and protection of the tapped holes, the shutter gate shall be processed in the same manner as the gate body.   The concave seating surfaces shall be re-machined where necessary.

The shutter gate arms shall be fitted with new bronze bushings where necessary.   Or, the original bushings shall be honed to established clean, smooth surfaces.   The arms shall be sandblasted and epoxy coated after the bushing are protected.   The adjusting screw tapped holes shall be checked, re-tapped where necessary, and fitted with new square head or hex head stainless steel, adjusting screws.   Each arm shall be assembled to its proper trunnion and checked for each of rotation.   Any trunnion defects shall be repaired.

The body/arms/shutterage assembly shall be carefully adjusted to produce the designed 0.006 to 0.010 inch clearances between the convex body seat face and the concave shutterage seat face.   These surfaces shall be perfectly mated with the use of a lapping/grinding compound and the repeated cycling of the assembly to lap one surface to exactly mate with the other.   Following the lapping process, all ferrous surfaces shall be lightly sandblasted again to remove dirt and grease and then epoxy coated.   Seating surfaces shall be protected during these processes.   After thorough drying, the components shall be reassembled and the clearances between the seating surfaces set and locked.

The trunnion cover plates can be reused if the surfaces are clean and capable of producing a seal.   Otherwise, new plates shall be furnished at no additional cost.  If perfect, the original retention studs can be reused.   But damaged studs shall be replaced at no additional cost and replacements shall be Type 316 stainless steel.   Grease fittings shall be replaced with Type 316 stainless steel alemite type.

The shutterage weight carrying bar shall be reused after sandblasting and epoxy coating.   On this shall be placed the required number and size of shutter weights to establish equal tension on the shutter linkage through its entire arc of travel.

If there is a wall between the gate chamber and the float chamber, and if the shaft passes through this wall, there is a center-bearing packing gland assembly.   This is attached to the masonry with anchors and cast iron lugs.   The anchors shall be replaced with stainless steel.   The bearing assembly shall be reconditioned by sandblasting, epoxy coating and replacement of the packing.

It is the intent of this specification to require the epoxy coating of all ferrous components excepting stainless steel.   Each piece shall be primed immediately following sandblasting, then covered with two coats of epoxy in accordance with the coating requirements for the project.   Surfaces shall be treated and application conditions and processes shall be in accordance with the instructions for the approved coatings that are used.

When all of the above processes have been completed, the entire regulator assembly shall be assembled in the shop and tested in the water.   Exact float submergence shall be established and recorded.   The shutter shall be balanced and the number of shutter weights that are required shall be recorded.   The entire assembly shall then be balance with the required counterweights added and their number, size and position recorded.   Float submergence, required weight information and any other information developed in the test procedures shall be added to a revised arrangement drawing and furnished to the Engineer together with the Operation and Maintenance guide.

The complete regulator shall be reinstalled in the chamber from which it was removed.    Capacity settings shall be as originally found unless these are changed by the written directions of the Engineer at the time of and in conjunction with the review for approval of the submittal drawings.

After all restored components are in place, the contractor shall provide certification that the materials used in the restoration are in conformance with this specification.   Another certification shall be required to state that the reinstallation is correct to the approved arrangement drawing.   The contractor shall be required to assure the continued correct performance for a period of one year following the date of the installation certification and to promptly correct any condition brought to his attention.

The contractor shall not be required to correct malfunctions that result from the accumulation of silt or debris or entrapments or malfunctions resulting from improper maintenance or changes by others of placements or settings of components.

Prior to the start of work, the owner shall provide for the cleaning of the regulator chambers and the removal and disposal of all materials that are not a part of the regulator, its chambers including the diversion chamber and their appurtenances.    Once cleaned, it shall be the responsibility of the owner to maintain clean conditions through the period of reinstallation of the components and beyond that period in accordance with the operation and maintenance requirements.

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