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Apache Stainless Equipment Corporation


Application Comparison of Stainless and High Alloy Materials

Apache’s background in pharmaceutical, medi­cal, water purification, and chemical industries has driven expertise in high-alloy material used in vessel construction.  The process application of a vessel or tank will determine the stainless or high alloy material specified for the construction of the vessel.  

Apache’s experience with stainless and high alloy material includes 304, 316, Duplex, Hastelloy, Monel 400, AL6XN, and Alloy 20.  Highlighted below is an overview of those applications.

304

304 stainless steel is widely used in food and life science production equipment. The strength, durability, and noncorrosive qualities provide the safety and cleaning effectives required under general conditions.

316

316 has high corrosion resistance and may be used in applications requiring higher strength and hardness. 316 material can be used for fuels, food processing, chemical, medical and pharmaceutical processes. 316 has a higher temperature performance than 314 and performs wells in cryogenic temperatures. 

Duplex

The Duplex series are extremely versatile stainless alloys, with many applications in fuel and chemical processing industries and pharmaceutical applications.  Duplex has low thermal expansion coefficients and high heat conductivity.  In Apache’s experience, the machineability may be more cost effective than 316 L and Hastelloy® material. 

Hastelloy®

Hastelloy® has sanitary advantages due to the high Nickel and Chromium content.  This material works well for the construction of heat exchangers, columns, and pressure vessels as well as nuclear and chemical reactors.  It is used in chemical process equipment applications and high-performance pharmaceutical vessels.

Monel® 400

Monel® 400 is resistant to sulfuric and hydrofluoric acids. Due to the cost, Monel® 400 is only used in applications where other materials will corrode.  The copper content of the material prevents an effective pickling finish. 

Al6XN®

AL6XN is used in low PH applications in food, oil and gas industries, reverse osmosis, scrubbers, and distillation columns. 

Alloy 20

Alloy 20 is used to manufacture pharmaceuticals, food, explosives, chemical and petroleum refinement. It is also used to construct heat exchangers, mixing tanks, and other heat resistance applications.

Apache’s operations and tank team with consult from steel supplier partners have developed a quick reference guide to highlight the composition, corrosion resistance, cost, availability, performance, and applications of the above stainless and high alloy materials.  Download our guide here.

The Apache Stainless Equipment Corporation employs experts in the fabrication of stainless and high alloy equipment for a range of industries.  Apache is accredited with ASME and more other global standards.   By setting service performance for our quality and compliance, we offer value for our compliance engineered equipment. 


3 Levels of Sanitary Vessels

Depending on the application, processors serving food or other hygienic industries have varying degrees of compliance requirements for custom vessels.  When working with your custom vessel manufacturing partner, it is important to identify the level of sanitary compliance in the pre-engineering discovery phase.

Apache defines three categories of sanitary design to help customers with the type of sanitary specifications for construction and fixtures to meet the vessel’s process goals.

BASE LEVEL

The base level sanitary vessel is cleaned manually. Typical construction fixtures include threaded coupling, threaded dip tubes and ANSI flanges.  Depending on the application, stock vessels may be used or modified. The material is 2B/Mill, or 304 or 316 stainless and is pickle passivated.

Customers use base-level sanitary vessels for waste tanks, hydrocarbon storage, food-grade applications, adhesives, and solvents.

MID-LEVEL

The type of sanitation is also a driver for more complexity in the design of sanitary vessels.  In the mid-level category, components are removed for cleaning or COP (clean out of place).

Mid-Level sanitary vessel designs are constructed with 304 or 316 stainless material and feature mechanical finishing and pickle passivation or nitric passivation.

Sanitary fittings are specified in a mid-level vessel from tri-clamp ferrules and tube connections to NA connects, flush mount outlet valves and sight glasses.

Customers use mid-level sanitary design vessels for material columns, solvent tanks, collection vessels, extraction, expansion chambers, mixing and dispensing.  

HIGH-LEVEL

The highest level of sanitary design vessel is automated to be cleaned-in-place (CIP). A 304 or 316 stainless material is specified for high-level sanitary vessels mechanically finished to less than 32RA (roughness average), with nitric and electropolish chemical finish.

The fixtures in this category are electropolished including tri-clamp ferrules, tube connections, NA connects, sight glasses, j-tubes, dip-tubes, and polished internal coils.

Customers using high-level sanitary vessels are involved in automated processing and manufacturing.  Applications for high-level sanitary designs include WRI tanks, R&D lab equipment, heating, and cooling vessels and nutsche filters. 

Each level of sanitary design can meet ASME UM, ASMEU, FDA, 3-A, CRN, PED, and BPE compliance requirements.

When exploring the project parameters for a custom vessel, our guide, “3 Levels of Sanitary Design Tanks and Vessels” , helps to drive conversations and specifications that will meet the vessel’s application, timing, and compliance requirements.

Apache Stainless Equipment Corporation manufactures stainless equipment for a range of hygienic industries. Apache uploads compliance engineering expertise in beverage, biotechnology, pharmaceutical, cannabinoid, food processing, and life science industries.


Comparing Base, Mid, and High-level Sanitary Finishes [Infographic]

Categorizing levels of sanitary design is helpful to professionals new to compliance regulated industries requiring custom vessels because it bridges communications regarding standards and design requirements.

In hygienic applications, stainless equipment requires a sanitary finish which generally refers to a smooth, scratch-free, non-corrosive finish.  The fineness of the finish, which determines its performance, is measured in RA (roughness average). The infographic illustrates the RA of different types of mill, mechanical, and chemical finishes.  The smaller the RA reading in microinches (height in millionths of an inch), the smoother the finish. 

When collaborating to qualify a project, we define a Base Level Finish as a 2B/Mill, 304 or 316 stainless materials that is pickle passivated.  The welds are continuous and crack and crevice-free.  This type of finish is paired with a Base Level Sanitary Design and is cleaned manually. Apache’s standard portable vessel line are an example of the base sanitary design and finish level.

A Mid-Level Finish is also composed of 304 or 316 stainless material and involves a secondary process of mechanical polishing greater than 32RA, with final finishing to include pickle or nitric passivation. The welds are continuous, crack and crevice-free, and are also ground flush and polished smooth to a specific RA.  Sanitary fittings, mechanical polishing, additional passivation processes and a cleanable design with removable components are categorized as Mid-Level Sanitary Design features.

Providing the smoothest RA readings is an electropolished finish after a series of processes, including mechanical finishing to less than 32 RA, passivation, and nitric passivation, which are common for High-Level Finishes.  The base material is 304/316 stainless. The welds are continuous, crack and crevice-free, ground flush and polished smooth to a specific RA designation less than 32RA.  The sanitary fittings are also electropolished.  Vessels with this level of specifications are typically cleaned automatically.

The specifications, construction and finishing of a vessel is often driven by standards and compliance requirements. All three categories, qualify for ASME UM, ASME U, FDA, 3-A, CRN, PED, BPE.

There are other factors that fall in these base, mid and high-level sanitary design categories, including construction features, processing applications and time to delivery.  Download our e-book “Guide to Sanitary Design for Custom Vessels in Hygienic Industries".


Anatomy of a Sanitary Design Vessel

When evaluating a custom vessel manufacturing partner for a new project, consider the manufacturing capabilities and experience that support the vessel’s application and sanitary requirements.

All custom design stainless vessels for the food, life sciences, pharmaceutical and health industries require sanitary construction. It is the application and automation that drives the level of sanitary componentry.

In reviewing each new custom vessel project, Apache identifies the sanitary requirements to categorize the vessel into a base, mid- or high-level design.  Apache offers a standard line of vessels that qualify for various regulatory compliance agencies.  However, these designs are considered a base level sanitary design, especially because the cleaning of the equipment is manual.  Apache identifies a mid-level sanitary design vessel as having COP (Clean Out of Place) components.

In the video, a custom vessel is animated to walk through characteristics and examples in the highest and most automated level of sanitary design custom vessels.

High-Level Sanitary Design Characteristics Include:

  • CIP (Clean in Place) Process and Components
  • Continuous, crack and crevice-free welds, ground flush and polished smooth to specific RA (Roughness Average) <32 RA
  • 304 or 316 stainless material, mechanically finished to <32 RA
  • Electropolished and Nitric passivated finishing
  • Electropolished sanitary fittings, including:
    • Tri-clamp ferrules
    • Tube connections
    • NA Connects
    • Flush mount outlet valves
    • Sight glasses
    • Orbitally welded j-tubes
    • Dip-tubes
    • Polished internal coils
    • Samples Ports
    • Spray devices
    • Control panels
    • External thermal jacketing

Processes and application in high-level sanitary design vessels include heating and cooling vessels, mixing and processing tanks, WFI tanks, filtering and R & D lab equipment.

Certification requirements is an important part of the sanitary design criteria.  Sanitary design standards include:

3A – A regulation of the design for processing equipment in the food and drug industries. A 3A certificate is proof of FDA compliance.

ASME U and ASME UM -  A regulation of the design of boilers and pressure vessels, including traceability of materials, procedures, testing and documentation.

BPE – A standard within ASME that drives equipment design for the bio-processing, pharmaceutical and other hygienic required industries.

In qualifying design, safety, automation other application details, Apache will facilitate the required compliance for the vessel and provide well communicated delivery, cost and approvals required for a successful project.


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