15-200 Cu. Ft.

Filter Press 15-200 Cu. Ft.

Filter Press 15-200 Cu. Ft.

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

1.1.1 American National Standards Institute (ANSI) Publication:

B16.5-81 Pipe Flanges and Flange Fittings

1.1.2 American Society for Testing and Materials (ASTM) Publications:

A36 Structural Steel

1.1.3 American Welding Society (AWS) Publication:

D1.1-84 Structural Welding Code, Steel

1.1.4 Steel Structures Painting Council (SSPC) Publication:

SP1 Solvent Cleaning

SP10 Near White Metal Blast Cleaning

1.1.5 Uniform Building Code (UBC) Publication:

1711 Guardrails


The dewatering press and appurtenances shall be furnished and installed to provide a complete and functional system.

Material and equipment shall be the standard products of a manufacturer regularly engaged in the manufacture of such products and shall essentially duplicate equipment that has been in satisfactory operation for at least 10 years.


Submit the following:

1.3.1 Manufacturer’s Catalog Data

Provide manufacturer’s data for the dewatering press and related control equipment, safety features, and appurtenances.

1.3.2 Shop Drawings:

Shop drawings for filter press and accessory equipment including principal dimensions and location of fittings. Data shall include weight and distribution of weight with the unit empty and filled.

1.3.3 Instructions:

Installation procedures shall be furnished prior to installation.

1.3.3 Operation and Maintenance Manuals:

Provide O&M manuals for the dewatering press and control systems.

1.3.5 The Customer/Contracting Officer will review and approve submittals.

1.3.2 Manufacturer’s Service Representative’s Report and Certificate: Submit service representative’s complete signed report of results of the inspection, operation, adjustments, and tests. Report shall include detailed descriptions of points inspected, tests and adjustments made, quantitative results obtained if such are specified, and suggestions for precautions to be taken to ensure proper maintenance. Include the manufacturer’s certificate that equipment conforms to specified requirements and is ready for permanent operation and that nothing in installation will render manufacturer’s warranty null and void.

1.3.3 Verification: Written verification on the fabricator’s letterhead that surface preparation and coating application were performed in accordance with the coating system manufacturer’s printed recommendations.

1.3.4 Certified Test Results: Submit test results, signed by the manufacturer, which indicate filter press is capable of handling specified effluent concentration, pH, fluid temperature and meeting specified sludge concentration and sludge cake volume. Test on this model shall have been done within the last 3 years.


1.4.1 Delivery and Storage:

Inspect materials delivered to site for damage; unload and store with minimum handling. Store materials on site in enclosures or under protective coverings. Protect materials not suitable for outdoor storage to prevent damage during periods of inclement weather, including subfreezing temperatures, precipitation, and high winds. Store materials susceptible to deterioration by direct sunlight under cover and avoid damage due to high temperatures. Do not store materials on ground. If special precautions are required, prominently and legibly stencil instructions for such precautions on outside of equipment or its crating. Store and protect materials according to manufacturer recommendations.

1.4.2 Handling:

Handle filter press in such a manner as to ensure delivery to final location in sound, undamaged condition. Take special care not to damage interior and exterior surfaces of filter press, and associated equipment. Make satisfactory repairs to damaged material(s) at no cost. Carry and do not drag materials. Handle filter press according to manufacturers information.


1.5.1 Inspection:

Examine each component of filter press for compliance with requirements specified. Redesign or modification of equipment to comply with specified requirements, or necessary redesign or modification following failure to meet specified requirements, shall receive particular attention for adequacy and suitability. This element of inspection shall encompass visual examinations and dimensional measurements. Noncompliance with specified requirements, or presence of one or more defects preventing or lessening maximum efficiency of filter press operation, shall constitute cause for rejection.


2.1.1 Filter Press Description

The filter press shall be a hydraulically opened and closed, side bar plate support, gasketed or non gasketed, floor standing filter press designed to efficiently dewater metal hydroxide slurry for handling as a dry cake and shall include all components necessary for a complete operating unit as specified herein. All components shall be new, free of defects or mechanical damage and in operating condition.

The filter press shall be manufactured to meet the following design parameters:

  • Design Operating Pressure 100 psig
  • Total Nominal Volume SEE FOLLOWING CHART
  • Total Filtration Area SEE FOLLOWING CHART
  • Plate Size 1,225 mm
  • Number of Chambers SEE FOLLOWING CHART
  • Cake Thickness 1.25 inches (32 mm)
  • Volume per Chamber 1.31 cu. ft.
  • Filtration Area per Chamber 26.7 sq. ft.
  • Influent Solids 1 – 4%
  • Influent pH 9 – 11
  • Minimum Filter Cake Solids 25%
Model Number
Total Nominal Volume
Total Filtration Area
Number of Chambers
15 cu. ft.
294 sq. ft.
20 cu. ft.
401 sq. ft.
25 cu. ft.
507 sq. ft.
30 cu. ft.
614 sq. ft.
40 cu. ft.
801 sq. ft.
50 cu. ft.
1,015 sq. ft.
60 cu. ft.
1,228 sq. ft.
70 cu. ft.
1,415 sq. ft.
80 cu. ft.
1,629 sq. ft.
100 cu. ft.
2,029 sq. ft.
150 cu. ft.
3,071 sq. ft.
200 cu. ft.
NOTE: Model numbers shown are for caulked gasketed plates, for non-gasketed plates, substitute -NG for -CGR

2.1.2 Filter Press Frame

The filter press frame shall be designed to maintain the filter pack in a closed position against an internal operating pressure of 100 psig plus a minimum clamping factor of 25% greater than the maximum internal operating pressure multiplied times the filter area of the tail filter plate. Minimum closure force shall be 120 tons.

The filter press frame shall consist of the fixed head stock, movable follower head, tail stock assembly, and side bars. The head stock shall be fabricated of structural solid ASTM A36 steel 3″ thick. Fabricated weldments and casting are not permitted. The follower head shall be fabricated of structural solid ASTM A36 steel 3″ thick. Fabricated weldments and casting are not permitted. The follower shall be mounted on two 2.5″ diameter Delrin rollers with a stainless steel insert, one per side, forming a set.

The follower head shall be attached to the hydraulic cylinder via a rod clevis, pivot block, and thrust bearing block that in combination permits a minimum 5° of misalignment between the movable head and ram.

The side bars are constructed of low carbon, A36 steel nominal 3″ X 12″ rectangular tubing. To ensure a straight side rail, solid steel side rails shall not be permitted. The side bars shall be welded directly to the head stock and tail stock, forming one continuous structural unit. Side bars that are “keyed” or bolted to the head and tail stock are not permitted.

To prevent corrosion of the sidebars due to surface finish erosion, the side bars shall come complete with 304SS wear caps. Wear strips that protect only the top surface of the side rail shall not be permitted.

The tail stock shall be fabricated of heavy duty 3/4″ web sections to provide adequate distribution of static loads.

2.1.3 Filter Plates

Filter plates shall be of the center feed, four corner discharge design for operation at 100 psig pressure at ambient temperature. Plates shall be of the gasketed or non-gasketed design. Plates shall be supported by integral handles molded onto the side of the plates. Bolt on handles which violate the integrity of the filter plate shall not be permitted. Plates shall come complete with filter cloths installed.

Recessed plates shall be molded from virgin, gray polypropylene and shall contain no fillers. Plates shall have a drainage surface design that shall provide adequate support for filter cloths and shall have at least four integrally molded stayboss supports equally spaced on the drain field. Plates without stay bosses will not be permitted.

2.1.4 Filter Cloths

Provide one set of filter cloths for the filter press. Cloths shall be installed on the filter plates. The filter cloths shall be polypropylene material, 14 oz. per square yard, multifilament, Oxford weave, 75 X 21 thread count, 2 – 3 scfm, calendared, and heat set.

2.1.5 Pneumatic Pulsation Dampener

To reduce the stress on the piping and minimize the surges from the compaction pump, the press shall be equipped with a pneumatic dampening device.

2.1.6 Air Blow Down Manifold

Provide discharge piping containing a four valve manifold. The manifold shall be designed to allow air to be blown through the press to remove any residual moisture at the end of the filtration cycle. The filtrate collection header shall be equipped with individual manual control valves for each corner discharge port. Discharge piping shall be manifolded to a single outlet. A common discharge header shall be built into the plates to collect filtrate and transfer to collection header on the press head section. The manifold piping shall be of PVC Schedule 80 material. The discharge valves shall be true union type ball valves of PVC construction.

2.1.7 Hydraulic Closure System

The pneumatic/hydraulic opening and closing system shall include one double acting hydraulic cylinder and one hydraulic power pack. The system shall be designed to automatically compensate for any thermal expansion or contraction of the plate stack as well as maintain the proper clamping force throughout the process cycle.

The hydraulic cylinder shall be capable of producing 120 tons of clamping pressure at a hydraulic pressure of 4,800 psig. The cylinder shall have a 8 inch diameter bore. The cylinder shall be of the tie rod design for ease of servicing hydraulic seals. The piston rod shall be covered by a flexible neoprene bellow to protect the rod from contamination and corrosion.

The hydraulic closure system shall consist of an air driven hydraulic pump, rotary control valve, hydraulic pressure relief valve, air on/off valve, hydraulic reservoir, and hydraulic cylinder. All components subject to high pressure shall be rated at a minimum of 5,000 psig. The hydraulic closure system shall be of a closed loop style. Use of air over hydraulic systems can result in contamination of the hydraulic fluid, do not extend the life of the hydraulic pump, and shall not be permitted.

2.1.8 Controls

All hydraulic components shall be integrally mounted in the tail stock. The hydraulic control equipment shall be enclosed within the leg and accessible to the operator. To prohibit unauthorized tampering of the air controls, the hydraulic system air pressure regulator shall be securely mounted in the enclosed tail stock.

The hydraulic control panel shall be leg mounted and shall contain no obstructions (such as a flip up lid) so that control status may be verified at a glance. To protect the integrity of the control panel, it shall be integrally mounted in the leg of the tail stock. The control panel shall not protrude from the surface of the leg. The control panel shall house only the air on/off switch, the hydraulic directional control switch, and the hydraulic pressure gauge. Superfluous gauges and switches not required for the operation of the press shall not be installed in the control panel and shall be mounted inside the tamper proof tail stock.

OPTIONAL 2.1.9 Low Hydraulic Interlock

The hydraulic closure system shall be equipped with a pressure switch. This switch is equipped with a dry contact to be used for feed pump control. During the filtration cycle, should hydraulic pressure drop below the required level, the sludge feed pump will automatically cease pumping.

OPTIONAL 2.1.10 Three Stage Pump Control

To achieve optimum cake consistency, a multi-stage sludge feed pump control system shall be utilized. The pump control system shall consist of two each field adjustable timers that index solenoid valves, allowing air pressure to the diaphragm feed pump to be increased in three steps. Three individual air regulators shall be included to regulate air flow to the sludge feed pump.

OPTIONAL 2.1.11 Press Full Indication

In conjunction with the three stage pump control, a flow sensing switch will be incorporated to detect the duration between pump strokes. A timer will be provided to set duration time that indicates a press full condition. A light on the three stage pump control panel face will indicate a press full condition. The press will automatically cease upon sensing a “press full” condition.

OPTIONAL 2.1.12 Semi-Automatic Plate Spreader

Press shall be equipped with a pneumatic plate spreader to separate the plates sufficiently to allow the filter cake to drop directly from the cavity. For operator safety, no moving components of the system shall have over 24″ total travel at any one cycle. To maintain proper alignment, the shifter shall have v-notch rollers. The rollers shall ride on 304 stainless steel rails. The plate spreader shall operate in a semi-automatic mode, requiring operator initiation of each plate shifting sequence. The plate shifting shall be accomplished with pneumatic operators. The plate shifter shall have the capability to shift individual or multiple plates per shifting sequence. No electricity shall be required for plate shifter operation.

OPTIONAL 2.1.13 Automatic Plate Spreader

Press shall be equipped with an automatic pneumatic plate spreader to separate the plates sufficiently to allow the filter cake to drop directly from the cavity. The plate spreader shall be controlled by a PLC and proximity switches. The plate spreader shall operate in a fully automatic mode. The operator may interrupt the cycle at any time to clear lodged filter cake. At restart, the system commences operation where the interruption occurred.

OPTIONAL 2.1.14 Catwalk and Platform

To provide direct discharge to a customer provided roll off container, a platform shall be utilized to elevate the press to an appropriate height. The platform will have catwalk around the perimeter of the filter press, allowing complete operator access. The platform shall have railings around the perimeter of the structure. The railings shall be designed such that a sphere 12 inches in diameter cannot pass through the open spaces between the intermediate rails. An access ladder shall also be provided. Typical height of this platform is 10’.

OPTIONAL 2.1.15 Sludge Dumpster

Sludge dumpster(s) sized to hold the entire contents of the filter press shall be provided. The dumpster(s) shall have ball bearing casters, fork lift pockets, and handle(s) so that the cart(s) may be moved by hand or with a fork lift truck. The dumpster shall be self dumping upon activating the release lever. The dumpster shall be mounted on curved rack and pinion that automatically displaces the center of gravity forward, prohibiting rapid dump of contents and destruction of equipment.

OPTIONAL 2.1.16 Sludge Feed Pump

An air operated double diaphragm sludge feed pump shall be provided. Pump shall be supplied complete with air filter/regulator and lubricator. Wetted components shall be cast iron. Pump shall be sized at 1½”.


2.2.1 Surface Preparation: The steel surfaces must be dry and clean in accordance with the following requirements. Remove all grease, oils and contaminants as outlined in SSPC SP1. Remove all weld splatter and grind burrs on cut edges and rough welds smooth. Blast clean all surfaces after fabrication in accordance with SSPC SP10 with profile depth of 1.5-2.5 mils. Apply first primer before any rust bloom forms.

2.2.2 Caulking:

All exterior non-seal welding joints shall be filled with rubber caulking before painting.

2.2.3 Exterior Surfaces:

Shop First Coat: Apply one coat average dry film thickness of two mils minimum, of a high-build catalyzed epoxy. Apply to all steel surfaces except the areas within 2 inches adjacent to field welds and surfaces specified to be hot-dip galvanized. The paint shall be Hempel 4563U.

Shop Finish Coat: Apply one coat average dry film thickness of 1.0 mils minimum, of a polyurethane paint. Recoat at time interval recommended by the manufacturer, the final coat shall be Hempel 5595U.

Third Coat: Field touch-up of damaged and unpainted areas shall be the same as specified first and second coats at the same film thickness.

The total average dry film thickness shall be a minimum of 4 mils.

PART 3 – TESTING/INSTALLATION3.1 Start-up Testing: Manufacturer’s field representative shall inspect and test unit and certify that the installation has been performed in accordance with manufacturer’s recommendations and that the system is ready for operation by others. Inspection shall consider, but no be limited to, the following:

  1. Soundness (without cracked or otherwise damaged parts).
  2. Completeness in all details, as specified.
  3. Correctness of settling alignment, set points and relative arrangement of each component.

3.1.2 Leak test tank and fittings both before shipment and after installation.


Hoffland Environmental, Inc.
10391 Silver Spring Road
Conroe, Texas 77303-1602

(936) 856-4515 phone
(936) 856-4589 fax
e-mail: [email protected]

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