Stainless Steel Acid Digestion Hood

What is the Stainless Steel Acid Digestion Hood?

A stainless steel acid digestion hood uses 304 or 316L stainless steel for the body and work surface. It suits high-throughput nitric and hydrochloric acid digestions where strength and heat resistance are needed.

Overview

This hood is built from 1.2–1.5 mm 304 or 316L stainless steel, welded and passivated to a smooth, cleanable finish. Stainless steel tolerates heat from hotplates and offers good resistance to nitric acid and dilute hydrochloric acid, though it is not suitable for hydrofluoric acid or hot concentrated hydrochloric acid. Internal height of 900–1200 mm accepts digestion blocks and rack systems. Airflow of 600–1500 m3/h gives face velocity of 0.4–0.6 m/s. A stainless or coated sash with tempered glass, IP65 lighting and service fittings are standard. The rigid structure suits multi-position digestion racks and heavy equipment, and the surface is easier to clean than PP in dusty, high-throughput laboratories. Optional sinks and drainage are fabricated in stainless steel.

How does it work?

An acid digestion hood encloses the hotplate or block digester on a chemically resistant work surface and draws acid vapours away through a rear baffle and exhaust duct. The body, liner and sash are made from polypropylene, PVC or acid-resistant stainless steel so that nitric, hydrochloric and hydrofluoric acid vapours do not corrode the surfaces. Face velocity at the sash is held at 0.4–0.6 m/s, and a corrosion-resistant fan, usually plastic or PVC-coated, moves air to atmosphere. Because digestion releases dense acid fumes and heat, larger air volumes and deeper baffles are used than in a general-purpose hood. Some models add a scrubber that neutralises acid in a packed column before discharge, reducing emissions to the stack. Water washdown and low dead volume help prevent salt accumulation and cross contamination between trace-metal samples.

What are the key features?

• 304 or 316L stainless steel body and liner
• Welded, passivated, cleanable surface
• Internal height 900–1200 mm for racks
• Airflow 600–1500 m3/h at 0.4–0.6 m/s
• IP65 lighting and service fittings
• Optional fabricated stainless sink

What are the technical specifications?

A typical stainless steel acid digestion hood configuration offers body material of 304 or 316L stainless steel, panel thickness of 1.2–1.5 mm, internal height of 900–1200 mm, width of 1200–2400 mm, face velocity of 0.4–0.6 m/s and airflow of 600–1500 m3/h. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Stainless Steel Acid Digestion Hood is used in high-throughput nitric acid digestion, metallurgical sample preparation, food and feed testing and pharmaceutical elemental impurity testing. Across the wider Acid Digestion Hoods class, laboratories also deploy it for trace-metal sample digestion, environmental soil and water analysis and food and feed elemental analysis.

Which standards and certifications apply?

Relevant standards and methods include EN 14175-2 (fume cupboards, safety and performance), EN 14175-3 (type test methods), ASHRAE 110 (method of testing performance of laboratory fume hoods), GB/T 34269, ASTM D1193 (reagent water used in digestion blanks) and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Install the hood away from doors and air supply diffusers, and provide corrosion-resistant ducting with the correct slope and drainage. Commission face velocity and, where required, containment by tracer gas at the sash. Establish a hotplate and acid-usage log, and inspect the liner, sash and fittings monthly for etching or discoloration. Replace exhausted scrubber media on the schedule set by the acid load, and treat scrubber effluent as acidic waste. Keep the work surface clean and free of salt deposits, especially around the inside of the duct connection. Provide secondary containment trays and confirm the fan, duct and roof discharge are rated for the acids in use.

How do I select the right Stainless Steel Acid Digestion Hood?

Choose stainless steel for nitric and dilute hydrochloric acid digestions that need a rigid, dimensionally stable enclosure. Do not use this construction for hydrofluoric acid. RFQ: acid grade and concentration, temperature, rack dimensions and duct route.

How does it compare with other Acid Digestion Hoods variants?

Choose the construction from the acids used. Hydrofluoric acid attacks glass and requires polypropylene or special liners; nitric and hydrochloric acid work needs polypropylene, PVC or acid-grade stainless steel. Decide whether a scrubber is required by local emission limits and the acid volumes handled. Match the internal height to the hotplate, rack and reflux glassware, and choose depth for tall condensers. Consider a dedicated water washdown system if the duct could collect salts. Select face velocity monitoring and alarms, and a work surface with a spill lip. Confirm the fan is corrosion-resistant rather than mild steel, and plan for acid-resistant duct material and drainage. Large multi-position digestions may need a walk-in or dual-duct layout.