Aerosol valve, operation

In a dry-box operation, a 3-ounce Fischer-Porter aerosol compatibility tube is loaded with approximately 10 g. of cesium fluoride and then equipped with a stainless-steel needle-valve adapter and a 323A Hoke valve, f After removal from the dry-box, Swagelokf connections are made from the valve to a metal standard-taper joint and the whole assembly attached to... 

Metered dose inhaler has been the most popular aerosol delivery device for the treatment of respiratory diseases, which is attributable to its portability and simple operation. Although seemingly easy to use, the MDI is a sophisticated device in design. The drug(s) are suspended or dissolved in a liquefied propellant system, which may also contain excipients such as cosolvents or surfactants. The formulation is kept pressurized in a small canister, sealed with a metering valve. Upon actuation through an actuator, the valve opens and the metered dose is dispensed as an aerosol spray from the expansion and vaporization of the propellant under ambient pressure. The inhalers may be used alone or with spacer devices, the electrostatic issues of which are considered in a later section. The present discussion focuses on the inherent charging of particles produced from MDIs. 

A final complication is the fact that closure systems (particularly those which assist in the dispensing or administration of a product) are becoming more complex and more sophisticated. The list which follows indicates many of the various closures and closure systems which are available for both primary and secondary packs as seals or closures can be temporary or permanent, certain packs may have a series of closures created by the way in which they are converted or manufactured. A tinplate built-up aerosol container, for example, has four permanent seals, i.e. welded or soldered side seam, a cone and a dome held to the container body by double seams, a swaged-in valve cup, and an operational valve system (the in-use closure). Some of the systems will therefore be described in further detail. 

For normal operation of an ICP source, at least three different gas flows are necessary cooling-, plasma- and aerosol carrier-gas. For special constructions of the "torch", other gas flows, e.g. a shielding gas, are used. Normally, argon is applied. For the improvement of the long- and short-time stability, special care must be taken with the gas regulating system, because all variations in the different gas flows influence the plasma and thus the emission conditions (e.g. observation height, RF-power, background etc.). Most sensitive in this connection is the carrier-gas flow. The normal needle valves and suspension-body flowmeter are not sufficient for an adequate operation of an ICP- or DCP-source. 

The Easi-Breathe is a breath-actuated metered-dose aerosol inhaler developed by Norton Healthcare. The device is primed when the mouthpiece is opened. When the patient breathes in, the mechanism is triggered and a dose is automatically released into the airstream. The inhaler works on a pneumatic principle. An internal vacuum restrains an operating spring. A valve that is operated in response to the patient s inhalation that allows the spring to fire the canister releases the vacuum. It can be actuated at a very low flow of approximately 20 L/min (72). Not surprisingly the device scored better than a pMDI on a number of features, including ease of use and having an attached mouthpiece cover. Practice nurses found it easier to teach and patients easier to learn to use than a conventional pMDI (73). 

A first round of the systematic review of the reactor operating eiqierience has been completed for the absorber rod drive mechanisms, main sodium pumps and intermediate heat exchangers (IHXs) which has revealed sensitive points for EFR. Examples are the importance of succeeding with the EFR features which prevent die sodium aerosol problems on the absorber mechanisms, the need to confirm adequate operational flexibility whilst avoiding the check valve at the primary pump outlet and to ensure full benefit is taken of the piston seal experience for the IHX / pool boundary replacing the gas bell originally selected for EFR. 

There are three major ammonia pipelines two in the U.S. and one in the USSR. One of the American pipelines (MidAmerica Pipeline System) transports ammonia from the Texas Panhandle to points in Kansas, Nebraska and Iowa. Its total peak capacity delivered to a number of points is 8000 t/day [22]. The other U.S. pipeline, the Gulf Central Pipeline, transports anhydrous ammonia from major producers along the Texas and Louisiana Gulf Coast to points in Iowa, Illinois, Nebraska, Indiana and Missouri [23]. Further information on the maintenance and repair of the MidAmerica Pipeline System is given in [24]. The total weight of ammonia in the MidAmerica Pipeline System, when full, is approximately 20,000 tons. Lock valves are 10 miles apart so it would be possible that 400 tons could get out between lock valves [22]. It is known from [12] that in one accident 700 tons of liquid ammonia leaked from the pipeline in the USSR. In the USSR pipeline accident, the aerosol cloud of ammonia covered a forested territory about 40 km in area however, all residents in the region were evacuated in time. Pipeline operations in the U.S. are governed by the national Gas Pipeline Safety Act of 1968, as amended in 1979 [17]. 

Figure 4 A beagle dog was anesthetized with thyamylal sodium (Surital) and intubated. The tidal volume, pulmonary artery pressure, lung resistance, dynamic compliance, trans-pulmonary pressure, and airflow are shown before and following administration of 14 breaths of an irritant. Laurie acid was heated, in a La Mer-type condensation generator (19), the vapor was condensed in a cold trap operated below 0°C. The response was due to the small particles and any vapors that were not deposited in this trap. This aerosol-vapor was administered for 14 breaths, using a time-controlled series of soleniod valves and thus only transpulmonary pressure and arterial pressure are displayed during the challenge.

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