Author: HWS Mainz Laboratory Engineering Team
Published by HWS Mainz – Specialists in Custom Laboratory Glass Systems and Process Technology

Introduction: Why Precision Filtration is Still a Pillar of Laboratory Excellence

In every high-performance laboratory, filtration is more than just a routine step—it is a critical control point that directly affects product purity, data reliability, and process efficiency. Whether you’re isolating an active pharmaceutical ingredient, separating solids from a reaction slurry, or purifying a final comp

ound before drying or crystallization, the filtration stage can be the difference between success and failure.

However, despite its central role, many filtration systems remain rigid, hard to clean, or poorly adapted to complex chemical workflows. For example,

traditional filter assemblies often lack compatibility with modern glass reactors, offer limited material flexibility, or cannot accommodate inert gas environments. These limitations are especially problematic in:

• Multi-step syntheses requiring intermediate filtration
• Handling of oxygen-sensitive compounds
• Research environments where rapid configuration changes are common 
• Laboratories striving to reduce cross-contamination and cleaning times

This is precisely the challenge the HWS Filtration Unit was designed to solve.

Developed by HWS Mainz, a long-established manufacturer of advanced laboratory glass systems, the HWS Filtration Unit brings a new level of adaptability, chemical compatibility, and process control to lab-scale filtration. Its robust glass/PTFE construction, optional inert gas handling, and fully modular design provide scientific teams with a reliable, easy-to-maintain, and integration-ready solution—whether for daily routine tasks or high-sensitivity R&D projects.

Not only is the HWS Filtration Unit technically sophisticated, but it also conforms to the workflow of each user. Rather than forcing users to adapt to a fixed system, it offers flexibility. It is compatible with pumps, reactors, and custom setups, and is available in multiple sizes and configurations. Therefore, the HWS Filtration Unit is engineered to meet the evolving needs of today’s scientific environments.

In this article, we’ll walk you through the features, advantages, real-world applications, and customization options of the HWS Filtration Unit. Ultimately, we’ll explain why this deceptively simple tool may become one of the most valuable components in your lab.

What Is the HWS Filtration Unit?

The HWS Filtration Unit is a modular, glass-based filtration system engineered for:

• High chemical resistance
• User adaptability
• Seamless integration into multi-step processes

It is ideal for both final cleaning steps and “on-line” filtration during reaction workflows. Consequently, it ensures clarity, reproducibility, and compatibility with a wide range of laboratory glassware.

Key Features at a Glance

Feature	Description
Residue-Free Filtration	Precision filter holder ensures even sealing and full media utilization
Glass & PTFE Construction	High resistance to acids, solvents, and temperature swings
Optional Inert Gas Connection	Protects oxygen-sensitive compounds during filtration
Modular, Customizable Design	Fully configurable to user needs (diameters, threads, fittings)
Clamp-Fixed Support	Easy setup with stainless steel support rods or brackets
Compatible with Common Filter Media	Use paper, mesh, or stainless-steel weave inserts

Anatomy of the Filtration Unit

The HWS Filtration Unit consists of four fully customizable components:

1. Head Piece (Borosilicate Glass)

• Screw-threaded for hose connections
• Can be customized in diameter, height, and fitting type
• Durable and thermally stable (borosilicate 3.3)

2. Filter Holder (PTFE)

• Seals with two FEP O-rings to prevent leaks
• Supports filter paper, fine mesh, or metal screens
• Interior ring holds filter securely without damage

3. Bottom Piece (Borosilicate Glass)

• Also screw-threaded for hose and system integration
• Configurable to work with different filtration and reaction setups

4. Clamp Fixation (Stainless Steel)

• Provides correct sealing pressure
• Includes support rod or bracket mounts for frame installation

Available in standard sizes from DN 50 to DN 200, each unit is precision-built and adaptable to your setup.

Why Lab Professionals Choose the HWS Filtration Unit

1. Versatility for Every Process

Whether you’re running a one-step purification or a multi-phase synthesis, HWS filtration units offer modular flexibility:

• Configure your own top and bottom glass sections
• Select from various filter diameters
• Use with any pump, vacuum line, or glass reactor system

2. Chemical and Thermal Resistance

Constructed from PTFE and borosilicate 3.3, this unit is suitable for:

• Strong acids and bases
• Organic solvents
• High-temperature or pressure-sensitive operations

3. Safe for Oxygen-Sensitive Compounds

When you’re filtering compounds like pyrophoric materials, Grignard reagents, or other air/moisture-sensitive products, the optional inert gas connection provides a sealed nitrogen or argon blanket. As a result, oxidation is prevented and compound integrity is maintained.

4. Designed for Practical Use

• Easy-to-clean construction
• Simple part replacement
• Can be mounted on frames or integrated into custom reaction setups

This is filtration built for the bench, not just the catalog.

Common Questions Answered

Can I use different filter types in the same unit?

Yes. The HWS filter holder accepts paper, stainless mesh, or PTFE membranes, depending on your application.

Is it suitable for vacuum-assisted filtration?

Absolutely. With tight O-ring seals and chemical-resistant materials, the unit performs well under vacuum and pressure conditions.

Can I upgrade later?

Yes. Thanks to the modular design, you can change the head, bottom, or filter holder later without needing to replace the whole unit.

Use Cases: How Labs Are Using HWS Filtration

• Final product cleanup before crystallization or drying
• Mid-reaction separation in step-wise syntheses
• Inline filtration for reaction monitoring or sample collection
• Pilot testing for pharmaceutical or fine chemical formulations
• Moisture/air-sensitive compound handling under inert atmosphere

Integration With HWS Glass Reactor Systems

If you already use HWS glass reactors, the filtration unit can be integrated directly into your setup using matching:

• Threads
• Flange sizes
• Clamp mounts
• Inert gas lines
  As a result, this creates a closed-loop workflow ideal for automated or continuous systems.

Conclusion: Filtration That Works With You

The HWS Filtration Unit was developed not just to meet lab requirements, but to exceed them. Its blend of modular engineering, inert-compatible sealing, and flexible integration makes it an essential tool for:

• Chemists seeking reproducible results
• Engineers developing automated lab workflows
• R&D labs working with sensitive or complex reactions

With HWS, you don’t adapt your process to fit the equipment. Instead, you adapt the equipment to fit your process.

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