Pneumatic needl

FIGURE 2.63 Pneumatic needle drive with needle guide and valve gate nozzle... 

The application of this type of standard specification makes possible manufacturing of moulds with a minimum injection by the precise separation of the cold sprue from the hot cavity. The sprue markings are minimal thanks to the pneumatic needle sealing system. Cycle times can be reduced because of the high temperatures of the cavity. As an ARBURG standard for example, cold runner systems are offered with up to four gate points. 

Hand and power tool cleaning is used on ships mostly for spot repair of damaged areas. Hand tools include scrapers, wire bmshes, and sanders. Electric and pneumatic power tools, which include grinders and needle guns, clean faster and more thoroughly than hand tools. Most power tools have vacuum lines coimected to collect paint debris. 

A non-pneumatic tyre which has an internal cavity which may be filled with sponge rubber or may be pressurised by inflation with an air needle. 

Fig. 11.5. Diagram illustrating the components of an ESI source. A solution from a pump or the eluent from an HPLC is introduced through a narrow gage needle (approximately 150 pm i.d.). The voltage differential (4-5 kV) between the needle and the counter electrode causes the solution to form a fine spray of small charged droplets. At elevated flow rates (greater than a few pl/min up to 1 ml/min), the formation of droplets is assisted by a high velocity flow of N2 (pneumatically assisted ESI). Once formed, the droplets diminish in size due to evaporative processes and droplet fission resulting from coulombic repulsion (the so-called coulombic explosions ). The preformed ions in the droplets remain after complete evaporation of the solvent or are ejected from the droplet surface (ion evaporation) by the same forces of coulombic repulsion that cause droplet fission. The ions are transformed into the vacuum envelope of the instrument and to the mass analyzer(s) through the heated transfer tube, one or more skimmers and a series of lenses.

In atmospheric pressure chemical ionization (APCI) ion-molecule reactions occurring at atmospheric pressure are employed to generate the ions, i.e., it represents a high-pressure version of conventional chemical ionization (Cl, Chap. 7). The Cl plasma is maintained by a corona discharge between a needle and the spray chamber serving as the counter electrode. The ions are transferred into the mass analyzer by use of the same type of vacuum interface as employed in ESI. Therefore, ESI ion sources can easily be switched to APCI instead of an ESI sprayer, a unit comprising a heated pneumatic nebulizer and the spray chamber with the needle electrode are put in front of the orifice, while the atmospheric pressure-to-vacuum interface remains unchanged. [48,138]... 

Optimum atomization is achieved by fine adjustment of the air cap and atomization air pressure measured at the nozzle. The binder solution is delivered to the nozzle port through a spray lance and tubing. The peristaltic- or positive-displacement pump is commonly used to pump the binder solution. The pneumatically controlled nozzle needle prevents the binder liquid from... 

Cleaning by hand tools is the oldest process. Today this is employed only when power tools are not available and where the surface is inaccessible to power tools and too small. The generally used hand tools are wire brush, scraper blades and chipping hammer and emery or sand paper. Hand held electric or pneumatic power tools for cleaning include sanders, pneumatic scalers, needle gun and rotary steel brushes. 

Metrohm and BAS have also introduced improved DME models capable of operating in the SMDE mode. The Metrohm electrode (Fig. 14.6b) has a needle valve and small-bore capillary. Much of it is pneumatically controlled. The BAS version (Fig. 14.6c) is called the controlled growth mercury electrode (CGME). It is based on the work of Kowalski, Osteryoung, and coworkers [30]. Its features include a low-resistance electrical contact to the mercury thread in the capillary via a stainless steel tube and a fast response valve. The fast valve has allowed unique experiments to be performed where precise control of mercury drop growth during the experiment is desirable [31-33]. The BAS (Fig. 14.7), EG G Princeton Applied Research (Fig. 14.8), and Metrohm (Fig. 14.9) electrodes offer this easy and reproducible drop renewal in fully equipped cell stands. 

Atmospheric pressure chemical ionization a solution of the sample is pneumatically sprayed at atmospheric pressure and the solvent is ionized by a coronary discharge from a needle. The monocharged ions produced cause the chemical ionization of the analyte and the ions are accelerated towards the vacuum region. 

Pneumatically powered devices fitted with a wide range of dosing needles are available for application of even the tiniest amounts of adhesive. Fig. 8. This means a high level of consistency in the adhesive amounts and surface areas - an important precondition for uniformly reproducible adhesive strength levels. Also, loss and waste of adhesive is minimized in such applications, so that very little waste disposal is required. Boiling in alkaline solutions completely depolymerizes and dissolves the adhesive. This facilitates reprocessing or dismantling of adhesively joined structural components. 

Alternatively, the pneumatic pressure can be held constant and a valve used to control the fluid flow. Needle valves, spool valves, and rotor valves are commonly used in this type of device. In all devices of this type, the fluid flow rate (0 is directly proportional to the material viscosity. Those factors that change the viscosity should be controlled carefully or the equipment must be able to compensate for the changes in order to achieve consistent results. 

Several terms for pressure measuring devices are used interchangeably including transmitters, transducers, gauges, sensors, and manometers. More precisely, a gauge is a self-contained device that converts a force from the process to a mechanical motion of needle or other type of pointer. A manometer is a term reserved for an instrument that measures the hydrostatic head of a liquid and generally operates near atmospheric pressure. A transducer or transmitter combines the sensor with a power supply and a converter— generally mechanical-to-electrical or mechanical-to-pneumatic. The sensor... 

Boiling point, 295 Melting point, C 131 Flashpoint,152 Relative density (water "i1) 1.5 Relative vapor density (air >-1) 5.1 Relative density at 20" C of saturated mixture vapor/alr(air-1) 1.0 Vapor pressure, mm Hg at 20 2.3xi0 Solubility in water, g/1(M ml 0.6 Explosive limits, vol% In air i. 7-10.5 Relative molecular mass 148.1 Gross formula WHITE CRYSTALLINE FUKES/NEEDLES OR POWDER Vapor mixes readily with air. In dry state can form electrostatic charge If stirred, transported pneumatically, poured etc. Can ignite spontaneously on exposure to air (if fine powder Is stirred up). Decomposes slowly on contact with water, forming — phthaiic add Reacts with oxidants reacts violently with nitric acid. ... 

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