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The Structure of a Mech-Chem Project

Mech-Chem Associates, Inc. is a full-service engineering firm specializing in the design, engineering and construction of manufacturing facilities, operating processes, and environmental control systems. Our design and build expertise is in the following applications:

    • Acid Recovery/Reclamation Systems

Tanks and piping systems

  • Fume Scrubbers & Exhaust Systems
  • Bulk Storage Facilities and Piping Systems
  • Chemical Delivery Systems
  • Wastewater Treatment & Recovery Systems
  • Chemical Milling & Etching Systems
  • Vacuum Evaporators

Process Design Capabilities

Mech-Chem's engineering professionals represent all the technical and engineering disciplines required for a complete process, system, or facility design including chemical, biochemical, geological, mechanical, architectural, structural, electrical, instrumentation, and environmental.

These professionals bring your production process, operating system, or recovery system from the conceptual design or development stage to full scale operation. At the beginning of each project, a complete analysis of the process, operating systems, and support utilities is made with the client by the design team.

An excellent example of our ability to design, engineer and construct complete systems is found is this Case Study of a project with the Wyman-Gordon Company.

Mech-Chem's ability to design, engineer and build a compete, fully integrated system with PLC/PC automation and controls comes from our wide range of capabilities, as seen in our project development process:/

1. Preliminary Process Design

In the preliminary process design phase, Mech-Chem researches and studies each project for technical and economic feasibility. Mech-Chem utilizes and provides the following methods to assess the client's process, equipment and control requirements:

  • Process Flow Diagram (PFD)
  • Energy and Material Balance
  • Piping and Instrumentation Diagram (P&ID)
  • Equipment and Facility Layout
  • Equipment/Mechanical Description
  • Instrumentation/Control Description

Mech-Chem provides a total and complete evaluation of the process design starting with the development of the Process Flow Diagram (PFD) and Piping and Instrumentation Diagram (P&ID). The P&ID establishes the equipment sizing and defines the piping, controls, and instrumentation requirements for the processes and operating systems including the appropriate support utilities.

During this phase of the project design, the process and operating parameters are defined including equipment sizing, material of construction, and regulatory compliance. The energy and material balances for each of the unit operations and process support utilities are established.

To ensure that you will gain the greatest benefits from our efforts, Mech-Chem assists you in keeping an eye on the bottom line through:

  • Capital Cost Estimates
  • Operating Cost Estimates

This financial information makes it easier for you to budget your capital expenditures and determine your cash flow and Return On Investment (ROI).

Mech-Chem is interested in the financial success of the project as well as the technical and engineering viability of the design. Mech-Chem guarantees that the project will be built for the capital cost estimate provided in our preliminary engineering design.

2. Detailed Process Engineering and Design

At the completion of the Preliminary Process Design phase and approval by the client, Mech-Chem Associates, Inc. then completes the detailed process, system, or facility design, including:

  • Piping and Instrumentation Diagram (P&ID)
  • Process Equipment Layout
  • Architectural/Structural Drawings
  • Mechanical and Piping Drawings
  • Electrical and Instrumentation Drawings
  • Detailed Equipment Specifications
  • Construction Bid Packages

The detailed design phase of the project provides all the specifications and drawings necessary for the construction of the process, system, or facility, including required support utilities and structures to support the equipment.

Our clients' systems and facilities are engineered and designed to assure compliance with all applicable federal, state and local codes, including:

  • Local Building Codes
  • EPA Environmental Regulations
  • OSHA Safety Regulations
  • NFPA Fire Protection Codes
  • BOCA Building Codes
  • API Codes
  • ASME Codes

The design drawings and specifications for construction are prepared in detail for architectural, structural, mechanical, piping, electrical, and instrumentation. The design drawings for the various construction disciplines are prepared using AutoCAD, Release 14 and can be prepared using the client's title block.

During the detailed design phase, Mech-Chem provides PE stamped drawings, as required, and can assist the client with obtaining environmental and construction permits.

3. Construction and Start-up

Being more than just a design firm, Mech-Chem provides turnkey construction for its systems and facilities. We procure and deliver the equipment to the plant site. We can also provide all the supervision, labor, and materials required for installation and construction including:

  • Equipment Procurement
  • Structural Construction
  • Equipment Delivery and Installation
  • Mechanical and Piping Installation
  • Electrical and Instrumentation Installation
  • System Start-Up and Operational Testing
  • Operation and Maintenance Manuals

During the construction phase of the project, Mech-Chem maintains engineers on-site to manage and supervise all aspects of construction. We provide the appropriate technical and engineering personnel for the testing and start-up of the equipment, operating systems, utilities, and training of client's personnel.

At the completion of the project, as-built drawings are prepared for the systems, facilities and utilities. In addition, the client is provided with operating and maintenance manuals and safety manuals for the equipment and operating processes.

To contact Mech-Chem, or for further information, use this form.

Wyman Gordon Company, Franklin, New Hampshire
Complete Design & Build Project

Wyman-Gordon is a world class materials company with nearly 200 years of metals engineering experience. They are the acknowledged leader in the production of high-quality closed-die forgings and extrusions for the most critical applications. Markets served include those for commercial and military aircraft; gas turbine engines; oil and gas exploration; land based gas turbine and power generation; commercial and military aerospace structures; and other markets where high integrity components are essential.

Wyman-Gordon's unique and far-ranging materials engineering capabilities and experience have positioned the Company as the world's only single source manufacturer of high-quality forgings, extrusions, investment castings and composite structures, with resources of equipment and people second to none.

Source: Wyman-Gordon Web Site (www.wyman-gordon.com)


The Casting Division of the Wyman-Gordon Company was considering constructing a new Acid Etch and Chem Mill Operation at the manufacturing facility located in Franklin, New Hampshire. To house the new operation, a building addition of 40' w x 100' l would be required.

To meet the Castings Division's projected production and site requirements, the installation of the new Acid Etch and Chem Mill Operation at this location had to encompass the following components and support systems:

  • Ventilation System with Fume Scrubber
  • Wastewater Recovery System
  • Acid Storage and Piping Systems
  • Waste Acid Storage and Piping Systems
  • Secondary Containment for Tanks, Equipment, and Tank Trucks
  • Building Addition to house the operation


Wyman-Gordon worked in conjunction with Mech-Chem to establish a design for the new Acid Etch and Chem Mill Operation with the following features:

1. Increase the volume in the acid etch and chem mill tanks from 250 gallons to 375 gallons to extend the life of the chemical baths.
2. Increase the basket size to provide a 50% increase in the number of small parts that can be processed per batch and a 100% increase in the number of large parts that can be processed per batch.
3. Provide an additional acid tank in the new Acid Etch and Chem Mill Operation which allows two baskets to be in production at the same time.
4. Add an alkaline cleaner tank and rinse tank to allow all components to be pre-cleaned before entering the acid tanks. Processing only clean parts extends the life of the acid baths.
5. The new acid tanks have an eductor system to provide agitation of the solution. This eliminates air agitation from the design, reducing the evaporative losses of hydrofluoric acid and nitric acid.

The facility also features a PLC control system built to NEMA 4X specifications, with a color display and a Windows environment for controlling the Chem Mill line.

The following describes the components of the facility:

Acid Etch and Chem Mill System

The new Acid Etch and Chem Mill System consists of the following components:

  • The Acid Etch and Chem Mill System have a total of nine tanks: one alkaline tank, four acid tanks, three cold water rinse tanks, and one hot water rinse tank.
  • The system uses new, larger chem mill rotating baskets, which are handled and transferred by an overhead crane structure.
  • Teflon coated electric heaters are installed in the tanks which contain solutions that require heating.
  • Teflon heat exchangers are installed in the tanks which contain solutions that require cooling.
  • A pump with eductor recirculating system was installed in all the tanks for agitating the solutions in the tanks instead of using an air agitation system.
  • The rinse tanks have countercurrent water flow.
  • All the tanks have level instruments with alarms for high/low level.

Ventilation System with Fume Scrubber

  • All the tanks in the acid etch and chem mill system, including the rinse water tanks, are equipped with push/pull ventilation.
  • The push/pull ventilation system is designed to meet the OSHA regulations for air flow and fume venting requirement for the chem mill and acid etch tanks.
  • The blowers for the push/pull ventilation system are mounted on the roof of the building to keep the noise level in the building below the OSHA regulations.
  • The fume scrubber is designed to meet the State of New Hampshire's DEQE current regulations for air emissions for HF and NO3.

Wastewater Recovery System

  • The Acid Etch and Chem Mill Operation uses deionized water in the hot and cold water rinse tanks for rinsing the parts and makeup of the acid baths.
  • The operation is designed to process the wastewater discharged from the rinse tanks through an ion exchange resin system which recovers the contaminated wastewater and provides deionized water for recycling back to the tanks. This allows approximately 80% of the wastewater generated by the operation to be recycled.
  • The ion exchange resin system is an automated dual bed (2-anion and 2-cation cylinders) unit which allows it to remain in operation continuously. The system is also equipped with prefilters before the resin beds.
  • The ion exchange resin system has a wastewater hold tank to feed the ion exchange resin system and DI water hold tank with a recirculating piping loop to the acid etch and chem mill system.
  • The backwash from the ion exchange resin system and the aqueous discharge from the fume scrubber are processed through a wastewater pretreatment system before being discharging to the local POTW. This system removes the metal ions, fluorides, and insoluble particulates from the wastewater.
  • The system has a final pH monitoring and adjustment tank with pH recorder and flow measurement which is required by Federal EPA regulations. Federal EPA regulations require final pH control and monitoring and continuous flow measurement for process wastewater entering a POTW.

Acid Storage and Piping Systems

The new Acid Etch and Chem Mill Operation requires storage and handling for hydrofluoric acid Hydrofluroic Acid Delivery System(HF), nitric acid (HNO3) and sodium hydroxide (NaOH) solution.

  • Hydrofluoric acid is small volume usage and is purchased, stored, and handled in 55 gallon drums. The drums are placed in a small containment unit and pumped through a double contained pipe to the acid tanks.
  • The nitric acid has a fairly significant volume of usage and is stored in a 5,000 gallon bulk storage tank. The nitric acid is pumped through a welded stainless steel pipe to the acid tanks.

Waste Acid Storage and Piping Systems

  • The concentrated waste acid solutions discharged by the treatment operation is pumped through a double containment pipe to a double contained waste acid storage tank.
  • The concentrated waste acid collected in the storage tank is then shipped off site for disposal. The storage tank and piping systems are designed to meet the EPA's current Risk Management and Certification requirements.

Secondary Containment for Tanks, Equipment, and Tank Trucks

There are several sections of the new Acid Etch and Chem Mill Operation which required secondary containment, including:

  • Secondary containment for the process tanks and wash down area.
  • Secondary containment for the ion exchange resin system and wastewater treatment system.
  • Secondary containment for hydrofluoric acid, nitric acid, and waste acid storage.
  • Secondary containment for bulk tank trucks for delivery of nitric acid and pick up of waste acid solution.


Wyman-Gordon's new facility not only allows for greater productivity and greater output, but is an environmentally friendly facility, with approximately 80% of the rinse water generated by the operation recycled into the process, proper secondary containment in all areas, and meeting all local, state and federal EPA regulations. The facility is designed to minimize the handling of hazardous chemicals and meet all local, state, and federal OSHA regulations.

Wyman Gordon Company, Franklin, New Hampshire
Complete Design & Build Project

Read the case study

Mech-Chem engineered, designed, and constructed two Air Emission Control Systems for the plant's Meltout Operations. The systems are non-aqueous processes which were designed to contain and remove metallic contaminants with a particle size of 0.3 microns or larger.

Air Emission Control System Mech-Chem provided GE Aircraft Engines with the design, engineering, construction, installation, and start-up of two Air Emission Control Systems that remove oil and lower the fugitive metal contaminants (i.e. Lead, Cadmium, Antimony, Arsenic, Bismuth, and Tin) in the air stream vented from meltout processes.

The Air Emission Control Systems met or exceeded the primary EPA Action Levels for the State of Vermont for Cadmium and Tin.

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