Industry Insights & Technical Resources

When purchasing venturi valves for fume hoods, what is most easily missed is not the valve diameter, but how much exhaust air volume is required at different openings of the window, and whether the valve can stably achieve these air volumes under on-site pressure differential conditions. An effective selection plan should cover the fume hood, exhaust pipe network, and laboratory air supply and exhaust control at the same time. Valve selection cannot be based solely on the width of the fume hood.

When selecting laboratory exhaust systems, buyers often compare VAV, CAV and Venturi Valve in the same quotation list. First, we must clarify a key difference: **VAV and CAV describe how the air volume is controlled; Venturi Valve describes the structure and control technology used in the valve. **Venturi valves can be used for constant air volume or variable air volume systems. The three are not mutually exclusive options.

Activated carbon filters are a common gaseous pollution control solution when VOCs, solvent odors or odors occur in industrial plants, laboratories, commercial buildings and HVAC systems. However, when purchasing, you cannot just compare the size and weight of activated carbon. What is more important is to clarify: type of pollutant → VOC concentration → treatment air volume → target outlet concentration → adsorption material → replacement cycle. Different VOCs have different adsorption characteristics. Only by clarifying the actual working conditions can the type of activated carbon, filter structure and service life be reasonably determined.

When a laboratory fume hood uses a Venturi Valve to control the exhaust, the valve cannot be selected based solely on the size of the air duct. The correct selection should be comprehensively determined from the fume hood exhaust volume, face velocity, minimum/maximum air volume, working pressure difference, control method, and room air supply and exhaust linkage. A reasonable selection process should be: Fume hood size → Face velocity → Qmin/Qmax → Venturi Valve range → Control signal → Room pressure difference linkage.

When shopping for bag, plate, or other HVAC air filters, it’s common to see two sets of grades together: EN 779: G4, M5, M6, F7, F8, F9 ISO 16890: ISO Coarse, ePM10, ePM2.5, ePM1 The two are not a simple replacement of old and new names. ISO 16890 changes the way filter performance is tested and evaluated, so F7, F8, and F9 cannot be directly converted to a certain ISO ePM level.

H13 and H14 HEPA filters are widely used in clean rooms, hospitals, pharmaceutical factories and laboratories. Model selection does not mean that the higher the level, the better. The particle control requirements, rated air volume, initial resistance and fan residual pressure should be combined to evaluate the filtration efficiency and operating energy consumption to determine the model suitable for the project working conditions.

In clean rooms, pharmaceutical factories, hospitals, electronic workshops and industrial AHU air treatment systems, you can often see G4, F7, F9 and H13 filters used in combination. But the real problem that needs to be solved when purchasing is not "install every level", but: Which filter levels must be configured? Do F7 and F9 need to be used at the same time? How many levels of filtering should be configured in front of H13? A reasonable multi-stage filtration system should reduce the particle load step by step and control system pressure drop, fan energy consumption and filter replacement costs while meeting terminal cleanliness requirements.

In AHU air handling units, fresh air systems, clean workshops and industrial ventilation systems, bag filters usually undertake medium-efficiency or medium-efficiency filtration tasks. When purchasing, we often encounter grades F5, F7, F8, and F9: Is the higher the grade, the better? Can F7 be directly replaced by F9? How should the number of bags and bag depth be determined? In fact, bag filter selection should not only look at the filtration level, but also need to consider the target particulate matter, rated air volume, initial pressure drop, installation space and whether the back-end is equipped with a HEPA filter.