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Write a review. Generally, any porous structure that can filter impurities contemplated for use as an exhale filter element in the invention. In order to reduce the pressure drop across the exhale filter element, it could be configured in a mold having ausgeweitetem surface area. For example, it could be corrugated or pleated, or it could be configured in the form of a filter in pancake form, which could be removably attached. The exhale filter element preferably contains a fluorine-containing s Additive s to impart better protection against splash fluids to the mask.
Juli , beschrieben. When the porous structure is fibrous, the fluorochemical additive preferably is incorporated at least into some or all of the fibers in the exhale filter element. In addition to or instead of the fluorine-containing additives mentioned other materials such as waxes or silicones can be used to prevent liquid penetration.
Essentially any product that may inhibit liquid penetration but not at the price that the pressure drop across the exhale filter element is significantly increased, is contemplated for use in the present invention. Preferably, the additive in the melt processable so that it can be incorporated directly into the porous structure of the exhale filter element.
The additives impart desirably repellency to aqueous fluids and therefore increase the oil repellency and hydrophobicity or are substances that reduce the surface energy. The exhale filter element is not only useful for removing impurities and preventing liquid penetration, but it can also be useful for removing unwanted vapors. Thus, the exhale filter element such impurities removal can have sorption.
The exhale filter element may be made from active particulate such as activated carbon, which is bound together by the polymer particles to form a filter element that may also include a nonwoven particulate filter as described above to provide dampfentfernende properties as well as satisfactory particulate filter capabilities.
An example of a bonded particulate filter is disclosed in U. Patents 5,,, 5,, and 5,, to Braun et al and U. An example of a filter element with a combined gas and particle capabilities is disclosed in U. Patent 5,, to Braun and Steffen. The exhale filter element could also as a nonwoven fabric, for example, melt-blown microfibers, be configured that carries active particles as described in U. Patent 3,, to Braun.
It has been found that meet or face masks with an inventive exhale filter element industry standards for characteristics such as fluid resistance, filter efficiency and comfort surpass. In the medical field, the bacterial filter efficiency BFE is used for face masks typically evaluated, which is the ability of a mask, particles, usually to remove from the carrier ejected bacteria. BFE-Tests sind so ausgestaltet, dass sie den Prozentsatz der Partikel auswerten, die aus dem Maskeninneren entweichen. BFE tests are designed such that they evaluate the percentage of particles that escape from the mask interior.
The percent penetration is the ratio of the number of particles downstream of the mask to the number of particles upstream of the mask. Face masks should also be a fluid resistance test where five test sets artificial blood under a pressure of 5 pounds per square inch PSI against the mask are driven.
If no artificial blood passes through the mask, it passes the test, and if any blood is detected, it fails. Masks with exhalation valve and exhale filter element according to the present invention were able to pass this test, both when the exhale filter element on the outside or ambient air side of the valve than if it is also arranged on the inside or face side of the exhalation valve.
Therefore, the filter face masks of the present invention can provide good protection against splash fluids when they are used. Wearer comfort improves when a large percentage of exhaled air to pass freely through the exhalation addition, rather than through the mask body or its periphery. Tests were conducted where a compressed air stream into the interior gas space of a face mask is conducted while measuring the pressure drop across the mask body. Gesichtsmasken mit einem Ausatmungs-Filterelement wurden wie folgt hergestellt. Face masks with an exhale filter element were prepared as follows.
The exhalation valves used are described in US Patent No. A hole with a diameter of two centimeters cm was cut in the middle of the TM 3M respirator of the mark, to accommodate the valve. The valve was attached sonic welder available using a Branson Danbury, Connecticut to the respirator.
Das Filterelement wurde auf verschiedene Weisen am Ventil befestigt. The filter element was secured in various ways at the valve. In another construction, the exhale filter element was placed over the valve cover and cut so that it is about one-half inch on all sides extended beyond the valve. Das Ausatmungs- Filterelement kann in dieser Weise auch unter Verwendung eines Klebstoffs befestigt werden.
The exhalation filter element can be attached in this manner using an adhesive. The fabric material stretched over the valve seat addition, was then tucked under the seat, and the wrapped valve was placed on the mask body over the opening. The assembly of the respirator, filter web, and valve was then ultrasonically welded together. From inside the mask the excess filter web was cut away, so that the valve opening has been left unlocked, and the filter fabric covered and the valve was sealed around the valve periphery thereof.
Juni 4. Friedrichs Jr. Die unten in Tabelle 1 umrissenen Gesichtsmasken wurden in einer luftdichten Kammer abgedichtet. The outlined in Table 1 below face masks were sealed in an airtight chamber. Air was pulled by vacuum through a high efficiency air particle HEPA filters into the chamber and then passed through the respirator, from the interior gas space to the exterior gas space, at a constant flow of Dies bewirkte, dass das Ventil offen blieb.
This caused the valve remained open. Paul, Minnesota was used on the inside or face side of the respirator a test aerosol of polystyrene latex PSL spheres available from to produce Duke Scientific Corp. Das Test-Aerosol wurde nicht ladungsneutralisiert.
The test aerosol was not charge neutralized. Paul, Minnesota Proben entnommen. Die BFE wurde als minus der Durchdringung berechnet.
November 5, In West Africa, masks are used in masquerades that form part of religious ceremonies enacted to communicate with spirits and ancestors. Verlag, Germany, American Tract Society. Practical Karate: Fundamentals Bk. They are conical masks, made from cane and leaves. Used Paperback Quantity Available: 1.
Langholtz und James L. The test set was produced by pressing of the nebulizer with a frequency of one presses per second, and there were upstream in the interior gas space and then downstream in the exterior gas space using a "Aerodynamic Particle Sizer" APS from TSI Company, St. Paul, Minnesota samples were taken. Only concentrations of particles in the size range 2. It has been found that in vitro methods such as these are more stringent than in vivo methods such as a modified Greene-and-Vesley test, described by Donald Vesley, Ann C. Langholtz and James L. Lauer in "Infection in Surgery", July Ergebnisse der Auswertung unter Verwendung der oben beschriebenen Untersuchungsmethode sind in Tabelle 1 dargestellt.
Results of evaluation using the test method described above are shown in Table 1 below.
In order to simulate blood splatter from the ruptured artery of a patient can be in accordance with the Australian Standard AS Appendix D for surgical face masks, published by Standards Australia Standards Association of Australia , 1 The Crescent, Homebush, NSW , Australia, allow a known volume of blood open at a known rate to the valve.
The investigation carried out was the Australian method similar, described with a few downward changes. A solution artificial blood was prepared by mixing milliliters ml deionized water, The valve with the valve diaphragm held open was placed 18 inches 46 cm away from a large 0. An artificial blood was squirted from the orifice and directly targeted to the opening between the valve seat and the open valve diaphragm.
The timing was set so that a volume of 2 ml artificial blood under a reservoir pressure of 5 PSI 34, Newtons per square meter was left out of the opening. The valve was tested five times with artificial blood.