Micro Piles  |  Pressure Grouting  |  Rock Anchors  |  Permeation Grouting   |  Micropile
Soil Nailing  |  Compaction Grouting  |  Micropiles  |  Chemical Grouting   |  Soil Nail Wall

    SECTION 15380

    SEWAGE TREATMENT EQUIPMENT GRINDERS

   PART 1 GENERAL

    1.01 WORK INCLUDED

    This section of the specifications covers the sewage grinder(s) to be installed as shown on the Drawings.

    The sewage grinder(s) shall be of the two-shaft design and be capable of continuous operation, processing wet or dry. Each unit shall include a grinder, hydraulic power pack with motor, motor, and control panel.

    1.02 REFERENCE STANDARDS

    A. American Iron and Steel Institute (AISI)

    AISI 4130 Heat Treated Alloy Steel

    AISI 4140 Heat Treated Hexagon Steel

    B. American Society for Testing and Materials (ASTM)

    ASTM A370 Test Methods and Definitions for Mechanical Testing of Steel Products

    ASTM A536 Ductile Iron Castings

    ASTM E18 Test Methods for Rockwell Hardness of Metallic Materials

   PART 2 PRODUCTS

    2.01 ACCEPTABLE MANUFACTURERS

    A. Furnish grinders as supplied by JWC Environmental and manufactured by Disposable Waste Systems, Inc.

    B. Minimum requirements for submission of an alternative manufacturer's equipment shall be the successful completion of "Proof of Performance by Demonstration" as described Article 3.01 of this Section.

    2.02 SEWAGE GRINDER(S)

    A. General

    1. Number of units: 2

    2. Type: Two-shaft design with two parallel shafts alternately stacked with intermeshing cutters and spacers positioned on the shaft to form a helical pattern. The two shafts shall counter-rotate with the driven shaft operating at approximately (2/3) the speed of the drive shaft. Shaft diameter shall be a minimum of 2 inches. Single shaft devices utilizing a single rotating cutter bar with stationary cutters will not be acceptable.

    3. Grinder cutting chamber shall be a minimum of 12 inches in height. The opening to the cutting chamber shall be a minimum of 8 1/2 inches in width.

    4. Required Running Torque per Horsepower.

    a. Continuously: 1600 in-lbs minimum.

    b. At Momentary Load Peaks: 2400 in-lbs.

    B. Materials

    1. Shafts of the cutting cartridge: AISI 4140 Heat Treated Hexagon Steel with a tensile-strength rating of not less than 149,000 PSI

    2. End Housings, Transition Flanges, and Covers: Cast of Class 30 Grey Iron

    3. Side Rails: Cast of ASTM A536-77 Ductile Iron

    4. Cutters and Spaces: AISI 4130 Heat Treated Alloy Steel, surface ground for uniformity and through-hardened to a minimum 43-48 Rockwell "C".

    C. Equipment

    1. Side Rails: The inside profile of the side rail shall be concave so as to closely follow the radial arc of the cutters. The side rails shall be affixed to the grinder so as to maintain a clearance not to exceed 5/16 inch between the major diameter of the cutter and the concave arc of the side rail thus assuring that particles larger than that clearance are directed toward the cutters to assure fineness of grind.

    2. Bearings and Seals: The radial and axial loads of the shafts shall be borne by four sealed oversize Conrad- type ball bearings. The bearings shall be protected by a combination of a tortuous path device and end face mechanical seals. Face materials must be a minimum of tungsten carbide to tungsten carbide, not requiring an external flush or any type of lubrication. The mechanical seal shall be rated at 60 PSI continuous duty by the seal manufacturer. The bearings and seals shall be housed in a replaceable cartridge that supports and aligns the bearings and seals, as well as protects the shafts and end housings. Products requiring continuous or occasional lubrication or flushing shall not be accepted.

    3. Individual Cutters and Spacers: The inside configuration of the cutters and spacers shall be hexagonal so as to fit the shafts with a total clearance not to exceed 0.025 inch across the flats to assure positive drive and increase the compressive strength of the spacers.

    4. Cutter Design

    a. The cutter design shall be of the 5-tooth design with bidirectional leading cutting edges on each tooth so as to cut equally well in either direction without removing the cutters from the grinder.

    b. To maintain particle size, the height of the tooth shall not exceed 1/2 inch above the root diameter. Cutter root diameter overlap shall not be less than 1/16 inch or greater than 1/4 inch to maintain the best possible cutting efficiency while incurring the least amount of frictional losses.

    c. The cutter shall exert a minimum force of 688 lbs per HP continuously and 1035 lbs per HP at momentary load peaks at the tooth tip.

    5. Couplings: The high speed shaft of the grinder shall be directly coupled with the motor using a two piece coupling.

    6. Motor: The torque motor shall utilize the hydraulic pressure developed by the power unit to provide the rotational torque required by the grinder.

    7. Motor Controller (Model Series PC 2030/2040): The motor controller shall utilize a programmable logic design with ladder logic programming. The controller shall provide thermal motor overload protection and single-phase protection.

    a. The controller shall provide the following functions:

    1) The controller is equipped with an "On", "Off", "Reset" switch. In the "Off" position, the electrical motor shall not run. In the "On" position, the unit shall run. In the "Reset" position, with spring return to "Off" the overload relay shall be de-energized. There shall be control logic which restricts resetting an overload condition from the remote connection. The unit can only be reset from the local panel controls.

    2) Operate in a normal ON/OFF mode. In the "ON" mode the unit shall automatically restart after a power failure.

    3) Motor heater coils are to be an integral part of an adjustable overload relay. The overload relay will detect single phase and phase imbalance with the motor full load amps (FLA) adjustable so that the range selected includes the FLA rating and service factor.

    4) If the unit encounters an overload condition and power failure occurs, the overload indicators will reactivate when power resumes.

    5) Upon the grinder encountering a jam or overload condition, the controller shall stop the grinder and reverse its rotation to clear the obstruction. If the jam is cleared, the controller shall return to normal operation. If the jam condition still exists, the controller shall go through eight additional reversing cycles within 45 seconds (nine times total) before signaling a grinder overload condition. Upon a grinder overload condition, the controller shall shut the grinder off and activate an alarm relay with dry contacts.

    6) Systems shall monitor all phases and record the following functions:

    a) Number of grinder reversals

    b) Number of grinder overloads

    c) Number of motor overloads

    d) "Power On" time

    e) "Run" time

    f) Low oil level

    g) High oil temperature.

    7) Service Indicator Lights will activate at prescribed times to alert the operator for potential action.

    a) Preventative Maintenance Indicator

    b) Full Service Indicator.

    8) Industry Standards

    a) UL approved

    b) Meets NEC requirements.

    9) Future Expansion Capacity: Controller shall have a minimum of one free digital input point and one free digital output point for interfacing the monitored functions and the full programmable capabilities of the Programmable Logic Controller with commonly used devices in wastewater applications.

    b. Motor Controller Hardware

    1) NEMA 4X fiberglass reinforced polyester enclosure complies with UL 508 standards.

    2) Indicator lights for Power On, Overloads, Run, low oil level, high oil temperature, and maintenance conditions.

    3) An auxiliary overload relay shall be provided for remote, overload and/or alarm indication.

    8. Hydraulic Power Unit:

    a. The hydraulic power unit shall consist of the following:

    1) 10 gallon capacity, epoxy coated reservoir

    2) Positive displacement pump driven by a TEFC, C face,vertically mounted 5 HP motor

    3) Combination oil level and oil temperature gage

    4) 10-micron return line filter

    5) Oil temperature limit switch set at 160 degrees Fahrenheit

    6) Oil level switch

    7) Filter breather

    8) Suction strainer

    9) Flexible hose and/or rigid piping rated for a minimum of 3500 PSI

    b. The rain-resistant power unit may be mounted in a remote location as required by design parameters in accordance with the manufacturer's recommendations. The NEMA 3R enclosure provided with duplicate cooling fans and louvers, drip shield, lifting lugs and stainless steel hardware shall be as recommended by the grinder manufacturer.

    c. The entire hydraulic system shall be designed for 3000 PSI maximum pressure. At idle load conditions system operating pressure should be in the 500 to 800 PSI range. Continuous operating pressure above 2000 PSI shall not be acceptable. As solids are encountered, pressure is automatically increased on a demand basis to provide the required torque necessary to continue rotation of the cutters. Should the grinder demand pressure in excess of 2850 PSI, a pressure witch is activated and a 4-way valve is shifted, instantly reversing the rotation of the cutters for approximately 1/2 to one revolution. At the end of this time the valve is again shifted and the cutters shall return to the forward direction.

    d. If the obstruction has been cleared, the unit shall continue to operate in the forward direction. If the obstruction has not cleared, the reversing sequence shall repeat until the torque requirement is reduced or until it has had to repeat the reversing cycle nine times within a 45 second time span. If nine reversals have occurred within 45 seconds, the electrical controller shall shut down the power unit and activate an audible alarm and alarm circuit (audible alarm is optional).

    e. The hydraulic power unit shall be filled with a high quality fluid with a viscosity of approximately 100 to 250 SSU at 100 degrees Fahrenheit with good chemical stability and anti-foaming properties. The grades of hydraulic fluid shall be in accordance with the recommendations of the manufacturer.

    D. Electrical Requirements

    1. Three phase, 60HZ, 230 volt (+) or (-) 5%.

   PART 3 EXECUTION

    3.01 PERFORMANCE

    A. Qualifications

    1. Proof of Performance by Demonstration

    a. A qualifying test of performance of grinding equipment shall be required between specified manufacturers. If alternate manufacturers are proposed, they shall also be subject to the qualifying test of performance. The test shall be conducted in the presence of the Engineer and the Owner's Representative. Test shall be conducted 30 days prior to the shop drawing submittal. All costs such as providing test materials, electric power hook-up etc. shall be borne by the Contractor. Grinding equipment manufacturers participating in the test shall cover their own costs of bringing the equipment to the site.

    b. Test equipment shall be of the same model number, size, horsepower and configuration as the unit to be provided under this Section. The performance test shall be a dry test.

    c. The test shall be conducted such that test materials are fed into the grinder by item. The full quantity of each item shall be fed at one time. Each group of items shall be fed at separate times. The grinder unit shall be allowed to clear after the full quantity of each item is fed through.

    d. The following occurrences shall be recorded:

    - alarms (based on 9 reversals)

    - motor overheat

    - motor overload

    2. Materials to be Tested

    a. The test materials shall be as specified below but not limited to:

    - 5 soda cans

    - 5 ea. 12-inch square rags (mechanical shop rags)

    - 8 pair of women's pantyhose (4 pair tied into three (3) knots each)

    - 4 medium size rubber gloves

    - 1/4 inch nylon rope, 20 ft. long

    - 2 pair athletic long socks

    - 1/2 inch wide steel strapping band, 5 ft. long

    - 1 woman's wig (synthetic or human hair)

    - A box of 12 plastic tampons with applicators

    - 1 broom handle cut into 1-foot lengths

    - 5 medium size disposable diapers

    - 1 pair size 8 canvas tennis shoes.

    b. The individually ground material shall be kept segregated for evaluation of particle size.

    c. A final list of materials to be tested and their quantities shall be supplied by the Engineer two weeks prior to the test.

    3. Categories of evaluation of test results shall include:

    a. Number of alarm status occurrences with number of motor overheat and motor overload situations counted. The alarm status shall be limited to two (2) alarms during the entire test. The alarm activation shall be based upon three (3) reversals.

    b. Before and after test verification of grinder motor amperage to verify motor nameplate data, rpm of cutter and motor reversal amperage. Motor reversal amperage shall be not more than 80% of locked rotor amperage.

    4. Hydrostatic Test

    a. Required for all in-line units.

    b. The alternative equipment must be certified that it meets or exceeds 90 PSI for 30 minutes without degradation.

    END OF SECTION

Rembco Geotechnical Contractors specializes in slope stabilization, foundation repair and support, shoring, grouting, soil nails, micropile installations, and sinkholes. We are experienced in these applications: micro piles, sinkhole repair, permeation grouting, pressure grouting, soil nails, chemical grouting, micropiles, compaction grout, rock anchors and compaction piles. Our specialties are rock anchor, chemical and compaction grouting, mini piles, sinkhole repair, micropiles, and soil nailing. We use a problem-solving approach in the geotechnical portions of buildings, bridges, water plants, sewage plants, tunnels, sinkholes, caisson, and roads. Rembco techniques apply when adding new real estate structures: especially rock anchor, microfine grouting, soil nailing, micropile installations for foundation support. Add URL Construction, Drilling and Concrete