Benchtop Perchloric Acid Hood

What is the Benchtop Perchloric Acid Hood?

A benchtop perchloric acid hood is a compact unit for one to six vessels with full washdown and a dedicated duct. It suits small perchloric acid digestions where floor space is limited.

Overview

This design places a small perchloric acid enclosure on an existing bench, typically 900–1500 mm wide and 700–900 mm deep, with the washdown manifold scaled to the shorter duct run. It holds a hotplate or block digester for one to six vessels. Face velocity is 0.4–0.6 m/s with airflow of 300–700 m3/h, and the exhaust must remain dedicated even at this small size. The liner is smooth polypropylene or stainless steel with coved corners, and the washdown cycle of 3–8 minutes wets the interior and the full duct. A timer, airflow monitor and interlocked sash are provided. The unit reduces floor space and duct length but limits vessel count and internal working height, so tall reflux columns may not fit.

How does it work?

Perchloric acid hoods work like other fume hoods but add a washdown system that periodically sprays water through the interior, the rear baffle and the entire exhaust duct. Heated perchloric acid vaporises, and its vapour can condense with organic material to form perchlorate salts in the duct, which are shock-sensitive and can explode. Water washdown dissolves these deposits before they accumulate. The hood and duct are constructed from non-combustible, chemically resistant materials with smooth, coved and crevice-free interiors and no sharp bends or horizontal runs where liquid or salt could collect. The washdown cycle runs for several minutes, typically daily or after each use, and drains to a dedicated chemical waste line. A dedicated exhaust system, separate from other hoods, prevents cross contamination and dilution problems.

What are the key features?

• Compact PP or stainless enclosure for bench use
• Capacities for 1–6 digestion vessels
• Washdown of interior and short dedicated duct
• Airflow 300–700 m3/h at 0.4–0.6 m/s
• Timer and airflow monitor with interlocked sash
• Coved corners, smooth cleanable liner

What are the technical specifications?

A typical benchtop perchloric acid hood configuration offers body material of Polypropylene or 316L stainless, width of 900–1500 mm, depth of 700–900 mm, vessel capacity of 1–6 positions, face velocity of 0.4–0.6 m/s and airflow of 300–700 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 Benchtop Perchloric Acid Hood is used in small perchloric digestions, research sample preparation, teaching demonstrations and quality control micro-digestion. Across the wider Perchloric Acid Hoods class, laboratories also deploy it for trace-metal digestion with perchloric acid, environmental and geological analysis and food and biological sample decomposition.

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), NFPA 45 (fire protection for laboratories using chemicals), GB/T 34269 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.

Never share the duct with other hoods, and never use the hood for organic solvents or for drying organic material, since perchloric acid and organics can form explosive mixtures. Run the washdown cycle before and after work and keep a log of cycles and cleaning. Inspect the duct interior for salt deposits on a defined schedule, using a borescope where needed, and clean any deposit with water rather than scraping. Keep all surfaces smooth and free of ledges, gaskets or insulation that could collect salts. Verify face velocity and alarms regularly, and train users to keep glassware away from baffles. Treat washdown effluent as acidic waste and confirm the trap and drain are compatible.

How do I select the right Benchtop Perchloric Acid Hood?

Choose a benchtop unit for one to six vessels when space is limited, but keep the exhaust dedicated. Confirm reflux glassware fits the internal height. RFQ: vessel count, acids, available duct route and drainage, and bench loading.

How does it compare with other Perchloric Acid Hoods variants?

Every perchloric acid hood must have a full washdown system covering the interior and the whole duct, because partial washdown leaves deposition sites. Choose a dedicated exhaust path with no shared ductwork, and specify smooth, all-welded construction with coved corners and no internal fasteners or ledges. Select the liner for the acids used: polypropylene or PVC for mixed acid work, and stainless steel or special alloys where hot concentrated perchloric acid is handled. Match the internal height to reflux glassware and the digestion block, and select airflow so face velocity stays at 0.4–0.6 m/s. Include a washdown timer or automatic cycle, drainage with an acid-resistant trap, and airflow monitoring with an alarm. Confirm the duct material, slope and washdown coverage in writing.