Air driven pump

Two serial reactors Ri and R2 with an internal volume of 8.3 ml, are fed with C02 by an air driven pump (2) through a preheating coil (3). The content of the reactors are mixed by two stirring devices (4) a pressure gauge (5) and a water bath (6) allow a precise setting of the P and T experimental conditions. By-passing of Rl can be achieved through an adequate combination of valves Vi to V4 A decompression needle valve Vs adjusted in combination with the pump, allows to set the levels of both flow rate and pressure within the apparatus. 

The input horsepower, in the case of an electrically driven pump, or the electri< horsepower, is the horsepower consumed by the motor, measured at its switchboard In the case of a steam-or air-driven pump, the input horsepower may be based on the steam or air consumption, computed at appropriate quantities per horsepower. 

The liquid solid chromatography was carried out using a Durapak "OPN" column (36-75 p particle diameter). The mobile phase, which ranged from 100% hexane to 70 30 hexane-isopropanol (v/v), was pushed through the 1 mm i.d. stainless steel column using an air-driven pump at sufficient pressure to deliver a 1.0 ml/min. flow rate. The detection was an ultraviolet monitor with an 8 pi cell volume operated at 254 nro. Sensitivity in the microgram range was reported. 

The analytical scale liquid-solid chromatographic separation of diazepam and its metabolites has been reported by Scott and Bommer in their study of the separation of benzodiazepines from each other and from biological media18. The liquid-solid chromatography was carried out using Durapak "OPN" (36-75y particle diameter) 100 cm column with a 1 mm inside diameter and hexane isopropanol (95 5 v/v) as solvent. The flow rate was 1.0 ml/min using an air driven pump. The detector was an ultraviolet monitor set at 254 nm. The... 

This particular FloJet could be enclosed in a positive pressure vessel, as was done with the process controller for this project. It could easily be slipped into standard PVC pipe fitted with screw-on pipe caps and a pressurization port. Also, an air driven pump and/or pulley driven pump could be used instead, or purchase a pump that is rated for hazardous environments. 

Up to now, we have entirely ignored the solvent that is used to displace the slurry in the slurry reservoir. Ideally, the solvent used to prepare the slurry should also be used to displace the slurry. However, there are some practical limitations for instance, the materials of construction in the pump may not be compatible with the slurry solvent. This is not an issue if HPLC pumps are used, but is of serious concern for air-driven pumps that may use elastomeric seals, which usually have a limited solvent compatibility. In tl case a different solvent needs to be chosen to push the slurry into the column. This solvent has several different requirements to fulfill ... 

Pressures up to 3 kb are probably most conveniently generated by means of a hand-pump or an air-driven pump. In the author s labora-... 

Advances in media, eluent materials, and air-driven pumps allow today s chromatographer to achieve the defined goals of preparative flash chromatography. Highly concentrated fractions are collected and transferred without contamination. Flash separations are performed quickly and as cheaply as possible. The need for more costly preparative HPLC has now been eliminated in many settings. 

Low oil pressure switehes are provided on the pumps and diseharge header ahead of the eoolers and filters, sometimes after the eooler and filters, and always at the end of the line where the redueed oil pressure feeds the various users. A signal from any of these should start the motor-driven pump and all alarms should be aetivated in the eontrol room. The emergeney oil pump ean be driven with an AC motor but from a power souree that is different to the standby pump. When de power is available, DC eleetrie motors ean also be used. Proeess gas or air-driven turbines and quiek-start steam turbines are often used to drive the emergeney pumps. 

In many designs, a combination of the choice items are used such as air- and water-cooling, steam and electric driven pumps and electronic and pneumatic instrumentation. As much as possible, these type decisions should be made by results of side studies rather than simple edict. 

The direction and flow rate of the test and hydraulic fluids are determined by nine three-way valves and six a1r-dr1ven hydraulic pumps that must be sequenced 1n the proper order. The position of the valves 1s determined by six air-driven actuators. Two of the pumps are miniaturized, air-driven, hydraulic pumps used for sample loading and pressurization. One of the remaining four pumps 1s a high-pressure, constant volume, positive displacement, piston metering pump to provide hydraulic pressure, and the other three are positive displacement syringe pumps for In-line addition of additives. 

Continuous injection is accomplished by drilling two wells into the oil sand deposit, one injection well and one recovery well. Into the injection well, air is pumped at high pressure, and bitumen at the base of the well is ignited. Air injection continues and moves the combustion process along as temperatures of 660°F to 940°F (350°C to 450°C) are attained. The bitumen is thermally cracked and vaporized. The cracked oils, gases, and vapors are driven toward the production well by injected air and recovered. 

But, when I put my hand here [on the air-pump receiver, which was afterwards exhausted], you see what happens. Why is my hand fastened to this place, and why am I able to pull this pump about And see how is it that I can hardly get my hand away Why is this It is the weight of the air-the weight of the air that is above. I have another experiment here, which I think will explain to you more about it. When the air is pumped from underneath the bladder which is stretched over this glass, you will see the effect in another shape the top is quite flat at present, but I will make a very little motion with the pump, and now look at it see how it has gone down, see how it is bent in. You will see the bladder go in more and more, until at last I expect it will be driven in and broken by the force of the atmosphere pressing upon it. 

To form a pendant drop, the gear pump (2) was switched off and the air driven oscillating double piston pump (4) with 1.8 ml per stroke was used. This pump has the advantage of keeping the volume constant in the apparatus while pumping. The drop size was controlled by closing the metering valve (5). 

Oil, used for lubricating the gears and bearings, is separated from the compressed airstream by labyrinth seals. Shown in Figure 3.31, the seals consist of two separate components, an air seal and an oil seal. In between the two, the seal is open to atmosphere. Any oil bypassing the oil seal leaks to atmosphere. The air seal is always at a higher pressure so that any leaks are always from air to atmosphere and oil cannot enter the process fluid. Oil is typically provided by a shaft-driven pump with a standby motor-driven pump available. 

Fig. 1.2 The principle of an air-driven reciprocating pump (V) a compressed-air distributor valve, and (C) one-way check valves. (Reprinted with permission from High Pres. Tech. (1977).)...

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