Valves lubricated

A cosolvent, typically ethanol, may be used to bring drug into solution. A small number of surfactants (sorbitan trioleate, oleic acid, and lecithin) may be dispersed in propellant systems and can aid in suspension stability and in valve lubrication. 

Annually Sprinklers free from corrosion, paint, and obstructions pipe free from corrosion control valves lubricated, closed and opened trip test on dry-pipe, pre-action, and deluge systems... 

Since most drags are insoluble in the propellants, they are usually presented as suspensions. Micronized drag is dispersed with the aid of a surfactant such as oleic acid, sorbitan trioleate or lecithin. At concentrations up to 2% w/w the surfactant stabilizes the suspended particles by adsorption at the drag propellant interface and in addition serves as a valve lubricant. The tendency is to use minimum surfac—tant concentrations to reduce drag solubility within the propellant by solubilization (to reduce Ostwald ripening during the shelf life of the pMDI). Low surfactant concentrations will also avoid substantial reductions in the propellant evaporation rates from aerosolized drops. 

Berry, J., Kline, L., Naini, V., Chaudhry, S., Hart, J., and Sequeira, J. (2004), Influence of the valve lubricant on the aerodynamic particle size of a metered dose inhaler, Drug. Dev. Ind. Pharm., 30, 267-275. 

Because CFCs are being relegated to history, this chapter will concentrate on the new HFAs. Three main factors control formulation approaches, and only one of these is pharmaceutical in nature. HFA 227 and HFA 134a are very poor solvents, hence the existing CFC sur-factants/valve lubricants are not soluble in the HFAs. The second factor which is related is that any new surfactant must have adequate drug safety data, and this could mean a full New... 

Many of the principles here are the same as for normal oral aqueous suspensions, except that the liquid is essentially non-polar, hence steric stabilisation is thought to be more important than by electrostatic means (DLVO theory). A stabilising agent is normally added to give an adequate suspension. The agent may also act as a valve lubricant, which may be necessary for... 

Equipment should not adversely affect the product through leaking valves, lubricant drips and the like or through inappropriate modifications or adaptations. 

The problem with the originally developed lubricated plug valves was the low resistance of the lubricants to heat, solvents and chemicals. Other problems were product contamination by the valve lubricants and. the expense and trouble required to lubricate and maintain this type of valve. Present day lubricants and coating of the plug surfaces have considerably reduced these problems. 

Lubricants for plug valves have been developed which contain a dispersion of gas that can be compressed to about half of its expanded volume. When the lubricant is forced into the valve under pressure it is compressed. Later, it expands and feeds automatically into the valve lubricant grooves only as needed, reducing lubrication frequency. 

Several lubricated plug valves are now coated with a fluorinated plastic (for service to 450°F) or molybdenum disulfide to make the valves easier to open and close. This improves the lubrocisity but at the same time would not let the valve leak if a fire melted the thin plastic coating. The valve lubricant would continue to seal the plug against leaks. 

Uses Valve lubricant and sealant that provides noncuring moisture barrier sealant for outdoor equip., incl. shipboard applies, subject to harsh environmental exposure chem. barrier coating damping medium for dash pots lubricant on gaskets, seals, and o-rings suitable for incidental food contact resinous/polymeric food-contact coatings Features Water, chem., radiation, and oxidation resist. 

Uses Valve lubricant and sealant that provides noncuring moisture barrier chem. barrier coating damping medium for dash pots lubricant on gaskets, seals, and o-rings... 

Lubricants, water repellents, defoamers, release agents, surfactants Valve lubricants, moistureproof sealants for electrical connectors, pressure-sensitive adhesives, personal care products Nonflow lubricants, polishes Electrical insulation, lubricant and paint additives, release formulations, water repellents... 

For lubricated plug valves, lubricate before putting into service. 

Reciprocating compressors have a history of chronic failures that include valves, lubrication system, pulsation, and imbalance. Table 8.3 identifies common failure modes and causes for this type of compressor. 

Uses Solubilizer, coupling agent, emollient for clear analgesic, deodorant, and fragrance sticks, bath oils, insect repellents, sunscreen preps., fodal cleansers, makeup, hair and skin care prods. cosolvent for many fatly compds. modifier extender vehicle valve lubricant and emollient in conventional sprays and lotions Features Low-vise. light skin feel... 

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