Glossary of Filtration Technologies: H

HEPA Filter

HEPA is an acronym for "high efficiency particulate air" filter. A HEPA filter is a type of an air filter which can remove at least 99.97% of tobacco smoke, household dust, pollen, bacteria and any airborne particles and particuletes with a size of 0.3 µm at 85 L/min.
HEPA filters are important in the prevention of the spread of airborne bacterial and viral organisms. Pharmaceutical and biotechnology type HEPA filtration systems also incorporate ultra-violet lights to kill the live bacteria and/or organisms trapped by the filter. Niro has developed a special HEPA filter for their pharmaceutical GMP compliant spray dryers.

HF

Hyper filtration; another name for reverse osmosis (RO).

High Fructose Corn Syrup (HFCS)

High Fructose Corn Syrup is extremely soluble and hygroscopic. The high fructose corn syrup story is one of the most "revolutionary" in food science in the last decade and the consumption has increased ever since its inception. HFCS are made up hydrolyzed (corn) starch.

High-Throughput Screening - HTS

High-Throughput Screening is a method for scientific analysis using robotics and other laboratory hardware enabling scientists to do thousands of tests at once.

HMWC

High Molecular Weight Component

Hollow Fiber Membranes

The hollow fiber geometry allows a high membrane surface area to be contained in a compact module. This means large volumes can be filtered, while utilizing minimal space, with low power consumption. Hollow fiber membranes can be designed for circulation, dead-end, and single-pass operations.

Homogenization

Homogenization (high-pressure) technology is based on high pressure forced on liquids to subdivide particles or droplets present in fluids into the smallest sizes (submicron) and create stable dispersions ideal for further processing. High-pressure homogenization creates a high concentration of energy which is released on the processed liquids or emulsions. This high pressure (energy) creates a number of fluid mechanical effects like cavitations, turbulence, shear and impact which result in a homogeneous particle size distribution. The process is carried out through a special valve (homogenizing valve), which represents the core of the homogenizing process. Homogenization is a term used in many fields such as chemistry, agricultural science, food & beverage technology, drug discovery, and cell biology. One of the oldest applications of homogenization is in milk processing, where the aim is to prevent or delay the separation of cream from the rest of the emulsion. The fat in milk normally separates from the water and collects at the top. Homogenization is the process of breaking up that fat into smaller sizes so that it no longer separates from the milk, allowing the sale of non-separating 2% and whole milk. This is accomplished by forcing the milk at high pressure through small orifices. GEA Filtration's sistercompany, Niro Soavi, is a world leading supplier of high-pressure pumps and homogenizers.

Hops

One of the four principal ingredients of beer. Added to beer as a bittering and flavoring agent, a preservative, an aromatic, as well as a stabilizer. The hop (Humulus) is a small genus of flowering plants, native to the temperate Northern Hemisphere.

Hormone

Hormone is a chemical messenger from one cell to another. Hormones are naturally produced by nearly every organ system and tissue type in human and animal bodies. All milk naturally contains hormones. References to hormones on milk packaging refer to whether the dairy farmers producing that milk use a supplemental hormone with their cows.

Housing

The part of the membrane filtration equipment holding spiral wound elements or other types of membrane elements, also referred to as pressure vessel.

Housing (Vessel)

The impermeable housing which forms the exterior structure of the module.

HTST Pasteurizer

A high temperature short time (HTST) pasteurizer - normally through a plate heat exchanger (PHE) or through a tubular heat exchanger.

Hydraulic Diameter

The effective diameter term commonly used when handling flow in noncircular tubes and channels.

Hydrocarbon

Hydrocarbons are organic chemical compounds of carbon (C) and hydrogen (H) whose densities, boiling points, and freezing points increase as their molecular weights increase. The molecular structure of the most common petroleum hydrocarbon compounds varies from the simplest - methane, a constituent of natural gas - to the very heavy and complex. Well known hydrocarbons include hydrogen and carbon bond structures such as oil, methane, propane, butane, etc.

Hydrogen peroxide

Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colorless in a dilute solution, slightly more viscous than water. It has strong oxidizing properties and is therefore a powerful bleaching agent that has found use as a disinfectant, as an oxidizer, and in rocketry, and in bipropellant systems. Hydrogen peroxide should really be called hydrogen dioxide. Its chemical formula is H2O2. It contains one more atom of oxygen that does water (H20). By now everyone's aware of the ozone layer that surrounds the earth. Ozone consists of three atoms of oxygen (03). This protective layer of ozone is created when ultraviolet light from the sun splits an atmospheric oxygen molecule (02) into two single, unstable oxygen atoms. These single molecules combine with others to form ozone (03). Ozone isn't very stable. In fact, it will quickly give up that extra atom of oxygen to falling rainwater to form hydrogen peroxide (H202).

Hydro cyclones

A hydro cyclone (a.k.a. hydrocyclone separator) is a process unit which utilizes centrifugal force to separate heavy particles out of water (or another liquid). In other words it is a device to classify / separate or sort particles in a liquid suspension. The separated material drops down into a tank or reservoir where it can be removed later. A hydro cyclone not a filter but it is often used upstream of a filter to first remove the bulk of the contaminant, where the filter does the final cleaning. A hydro cyclone can often replace a centrifuge (mechanical separator) and a centrifuge (a.k.a. separator, clarifier, etc.) can always replace a hydro cycle - although the centrifuge typically will be more expensive.

Liquid hold up in a hydro cyclone is in the range of seconds. The solids-liquid (S/L) separation is based on centrifugal forces and the difference between specific gravity of water and solids. Produced water is injected under pressure tangentially. The conical shape of the cyclone causes an increase of speed, resulting in large centrifugal forces and separation of solids from liquid. The heavier solids will move in a vortex towards the exit of the cyclone, whereas the lighter liquid will move in a secondary vortex in the centre of the cyclone towards the top of the hydro cyclone.

In a suspension of particles with the same density, a relatively sharp cut can be made. The size at which the particles separate is a function of cyclone diameter, exit dimensions, feed pressure and the relative characteristics of the particles and the liquid. Efficiency of separation is a function of the solids concentration; the higher the concentration, the lower the efficiency of separation. There is also a significant difference in suspension density between the base exit (fines) and the apex exit, where there is little liquid flow.

If the size range of the particles is limited, but there are differences in density between types of particle, the denser particles will exit preferentially at the apex. Hydro cyclones have a compact footprint which also make them desirable for offshore application. The typical use of hydrocyclones is in wastewater application but numerous process applications also utilize hydro cyclones - the best know is probably for starch recovery as hydro cyclones are much cheaper than the more effective decanters. Hydro cyclones are generally placed between the primary separation and filtration. They are reliable with no moving parts. Hydro cyclones have high energy requirements for inlet pressure.

GEA Filtration have made several membrane filtration installations where hydro cyclones have been integrated upsteam before the membrane filtration plant.

GEA Filtration - cross-flow membrane filtration, alone or in combination with other technologies, provides substantial opportunity for isolation, purification or concentration of very specific and tailored components of food, dairy, chemical, pharmaceutical, biotechnology, and nutraceutical products.