Liquid Nebulizers

Gas-powered jet nebulizers have been in clinical use for more than 100 years. Most modern jet nebulizers are powered by high-pressure air or oxygen provided by a portable compressor, compressed gas cylinder, or 50 psi wall outlet. Too low a gas pressure or flow can result in negligible nebulizer output. Consequently, nebulizers used for home care should be matched to the compressor being provided. Manufacturers and suppliers should be asked to provide information on particle size and output for any nebulizer/compressor combination provided for home or hospital use.

There are four categories of SVNs: 1) constant output nebulizer with simple reservoir tube; 2) constant output nebulizer with collection reservoir bag; 3) breath-enhanced nebulizer (BEN); and 4) breath-actuated nebulizer (BAN). This is the most commonly used SVN. Aerosol is generated continuously, with 30% to 60% of the nominal dose being trapped as residual volume in the nebulizer, and more than 60% of the emitted dose is wasted to the atmosphere. Many disposable SVNs are packaged with a 6-inch (15 cm) piece of aerosol tubing to be used as a reservoir. This may increase inhaled dose by 5% to 10%, increasing the total inhaled dose from 10% to 11% with the reservoir tube.

Constant Output Nebulizer with Collection Resevoir Bag Bag reservoirs hold a portion of the aerosol generated during exhalation and allow the small particles to remain in suspension to be available for inhalation with the next breath, while larger particles rain out. These systems may increase inhaled dose by 30% to 50% over standard continuous jet nebulizers. The collection bag on the expiratory side of the nebulizer T collects aerosol, leaving the SVN when the patient is not inhaling and allowing some of the aerosol in the bag to be inhaled with the next inspiration. These devices increase inhaled dose compared to conventional nebulizers. The bag reservoir is difficult to dry between doses.

BREATH-ENHANCED NEBULIZERS Breath-enhanced nebulizers generate aerosol continuously, utilizing a system of vents and one-way valves to minimize aerosol waste. An inspiratory vent allows the patient to draw in air through the nebulization chamber generating and containing aerosolized drug. On exhalation, the inlet vent closes, and aerosol exits by a one-way valve near the mouthpiece. This process increases inhaled mass by as much as 50% over standard continuous nebulizers (up to 15%), and partially reduces aerosol waste to the atmosphere.

Sieve Cleaner: How to Thoroughly & Efficiently Clean Your ...

Steel, brass and ceramic sieves are used in labs to identify the physical and chemical properties of a wide range of solids. In order to study and determine the size and shape of the particles, fineness, flow characteristics, etc labs need sieves of different grades to carry out ‘gradient’ or ‘particle size distribution’ tests. The sieves used in research labs are referred to as ‘analytical’ sieves as their mesh is typically small at 200 mm or less.

Organic and inorganic materials like sand, coal, soil, feldspars, crushed rock, granite, clay, seeds and grain, etc undergo sieve analysis as it is a very simple method of deducing particle sizes. Sieves with larger mesh dimensions are easy to clean. It only requires gentle tapping on the sides of the frame of the sieve, cleaning it with a sieve brush followed by running a fine cloth over it. These small and easy steps are enough to get these sieves all set for future tests.

On the other hand, coarse particles tend to get trapped in the analytical sieves’ very fine mesh. The problem is they reduce the accuracy of future analyses unless they flushed out periodically. Constant use can cause these cleaners to become extremely dirty because of the intrinsic properties of the materials that are studied for experimental purposes.

Analytical sieves require vigorous cleaning due to their extremely small crevices. Most commonly used are the 200mm diameter sieves. They are primarily used for sieving chemical compounds, a samples of industrial products, soil and cement. The most efficient way to clean them is through ultrasonic cleaning . Contaminants of all sizes are effectively removed using ultrasonic cleaners. They produce ultrasonic waves that generate powerful vibrations by a process called cavitation to free the particles stuck in the sieve.

 These ergonomic units allow full-immersion cleaning that are extremely easy to operate. Before, most of the ultrasonic cleaners manufactured could not accommodate a 200mm sieve for extensive cleaning . Fortunately, sophisticated and efficient ultrasonic cleaners manufactured today have have simplified the normally tedious task of cleaning analytical sieves. A 200 mm diameter, eight-inch sieve can substantially be placed in these stainless steel-made cleaners. Their average volume is nearly a gallon and a half or nearly six liters.

One of the high-end units available in market is the ultrasonic sieve cleaner that comes with a built-in rotation holder. In the busy lab, this is a productivity boon. Four sieves can be fitted into the holder and cleaned simultaneously.  It has a volume of nearly seven and a half gallons or twenty eight liters. The added function of rotation delivers better results since it makes the entire cleaning highly intensive. What’s more, the cleaning process is also faster with these units.. When compared with cleaners that lack rotation holders, this combined technology incorporated into one unit saves the lab a lot of time and money.

Particle Size Measurements, Fundamentals, Practice, Quality

Principles, Methods and Application of Particle Size Analysis

Code of Federal regulations, containing a codification of documents of general applicability and future effect as of December 31, 1948, with ancillaries and index

Wood-plastic composites

Symposium on particle size measurement, presented at the sixty-first annual meeting, Boston, Mass., June 26 and 27, 1958