Vacuum extractors

Patty Jones checks the operation of an automatic mechanical vacuum extractor in the chemistry section of the Natural Resources Conservation Service (NRCS) Soil Survey Laboratory in Lincoln, Nebraska. 

The analyzer operation is based on mass-spectrometric principle. The probe preparation system consists of vacuum extractor and oven. 

Neither soxhlet extraction nor steam distillation is designed to isolate volatiles from solids for subsequent determination. Slurrying the solids in water and then applying the PaT procedure has been reported A vacuum extractor with cryogenic concentration has been applied to both fish and sediment samples for determination of volatile priority pollutants PaT, LLE, and static headspace techniques have all been applied to the determination of volatiles in sludges from municipal waste treatment plants... 

Mechanical dewatering Squeeze roll Vacuum extractor... 

Obstetrics. Most pregnancies progress uneventfully through delivery however, complications can arise suddenly. The majority of women deliver vagi-nally some of these deliveries are assisted by the use of forceps or a vacuum extractor (a suction device applied to the fetal head). Some deliveries are conducted via a cesarean section (operative delivery) because of problems that arise during labor or the intrapartum period. Common reasons for cesarean sections include lack of progress during labor or the development of fetal distress. 

To prevent losses, air currents must be strictly avoided while scraping off the spot and transferring the powder to a suitable vessel. Various authors have accordingly used vacuum extractors, with which the localised spots could be sucked on to the filter surface or into the extraction flask and then eluted [65, 70,123, 318, 349, 437, 451,463, 578, 605, 651]. 

Fig. 80. Vacuum extractor of Matthews et al [437], available also for removiug spots from the plate by suction. A tube with which the spot is sucked off B glass filter (G 4) on which the powder is collected C ground glass joint fitting an appropriate standard flask...

Mechanical dewatering Squeeze roll Vacuum extractor Thermal drying Steam can Convection dryer Radiant predryer... 

Considering the osteopathic structural findings in this case, the risks involved with vacuum extraction, the patient s wishes for a natural birth, and the absence of fetal distress at the time, consent was obtained for a trial with osteopathic manipulation before attempting delivery with the assistance of a vacuum extractor. 

Osteopathic treatment was successful. Baby R. was delivered without the assistance of the vacuum extractor. Her APGAR scores were 9... 

As seen in this case, osteopathic manipulation maybe a useful treatment modality to assist normal vaginal delivery before using forceps or a vacuum extractor, thus potentially preventing complications to mother, child, or both. 

As demonstrated in this case, the tension of the iliopsoas and restrictions found at the sacroiliac articulations may impede descent of the fetal head. Prolongation of this stage may very well result in maternal fatigue and the inability to deliver the child by usual means. If normal vaginal delivery is unfeasible, assistance with instrumentation, such as forceps or a vacuum extractor, may be attempted. The indications for vacuum assisted delivery include maternal exhaustion and inadequate expulsive efforts. Suction forces used with vacuum extraction range from 12 to 18 pounds per square inch. Further, vacuum extraction carries a risk of complication three times greater than normal vaginal delivery. 

Putta LV, Spencer JP. Assisted vaginal delivery using die vacuum extractor. Am Earn Phi/sician 2000 62 1316-1320. 

Fig. 38. Caustic purification system a, 50% caustic feed tank b, 50% caustic feed pumps c, caustic feed preheater d, amonia feed pumps e, ammonia feed preheater f, extractor g, trim heater h, ammonia subcooler i, stripper condenser j, anhydrous ammonia storage tank k, primary flash tank 1, evaporator reboiler m, evaporator n, caustic product transfer pumps o, purified caustic product cooler p, purified caustic storage tank q, ammonia stripper r, purified caustic transfer pumps t, overheads condenser u, evaporator v, evaporator vacuum pump w, aqueous storage ammonia tank x, ammonia scmbber y, scmbber condenser 2, ammonia recirculating pump aa, ammonia recycle pump. CW stands for chilled water.

Extraction. Traditionally tea leaf is extracted with hot water either in columns or ketdes (88,89), although continuous Hquid soHd-type extractors have also been employed. To maintain a relatively low water-to-leaf ratio and achieve full extraction (35—45%), a countercurrent system is commonly used. The volatile aroma components are vacuum-stripped from the extract (90) or steam-distilled from the leaf before extraction (91). The diluted aroma (volatile constituents) is typically concentrated by distillation and retained for davoring products. Technology has been developed to employ enzymatic treatments prior to extraction to increase the yield of soHds (92) and induce cold water solubiUty (93,94). 

The endless-belt percolator (Wakeman, loc. cit.) is similar in principle, but the successive feed, solvent spray, drainage, and dumping stations are hnearly rather than circulany disposed. Examples are the de Smet belt extractor (uncompartmented) and the Lurgi frame belt (compartmented), the latter being a kind of linear equivalent of the Rotocel. Horizontal-belt vacuum filters, which resemble endless-belt extractors, are sometimes used for leaching. 

The PVAc latex was cast 1.8 mm in thickness on a poly(-ethylene) plate and dried at room temperature. The latex film was dried further in a vacuum desiccator for 24 h, and extracted in Soxhlet extractor with acetone for 20... 

The liquid is transferred to a continuous extractor (Note 10) and extracted with ether until the supernatant layer of ether remains colorless (about 2 hours). The ethereal extract is discarded (Note 11). The aqueous solution is transferred to a 1-1. beaker and acidified by the cautious addition of 60 ml. of 121V hydrochloric acid (Note 12). The solution is returned to the extractor, which is attached to a tared round-bottomed flask. The solution is extracted with ether until no more -hydroxyphenylpyruvic acid is obtained (Note 13). The undried ether solution is evaporated to dryness on a boiling water bath to give crude p-hydroxy-phenylpyruvic acid as a pale-yellow crystalline mass. The mass is broken up with a spatula, and the flask is kept over potassium hydroxide in a vacuum desiccator until its weight is constant. The yield of crude acid is 6.9-7.2 g. (92-96%). It melts at 210— 215° (dec.) (Note 14). 

This cycle of vaporisation of the solvent, condensation, extraction, and vacuum-filtration may be repeated any number of times in a solid-fluid serial extractor. The occurrence of an extractive material fluid bed as a result of the flow of boiling hot vapour provides for effective extraction, while pressure filtration provides for short cycle times. This functional principle makes it possible to achieve filtration pressures which are 50-100 times more effective than when using the Soxhlet method, where only the low hydrostatic pressure of the extractive fluid operates. Solid-fluid-vortex extraction according to the proprietary FEXTRA (Feststoff Extraktion) principle is low cost. 

Dissolve 3.3 g 4,5, or 6 methoxy (or ethoxy, methyl, etc.)-tryptamine or its HC1 salt in 350 ml 0.1 N HC1 heat on steam bath two hours with 1.1 g glycoaldehyde (reaction over when aliquot no longer gives a precipitate with dinitrophenylhydrazine). Filter, concentrate by heating on water bath or evaporate in vacuum basify with 20% NaOH and extract with ether (best to do in an extractor for eighteen hours). Dry and evaporate in vacuum the extract to get about 5 g residue or oil which may precipitate on standing. Add 250 ml 90% phosphoric acid and heat on steam bath two hours. Evaporate in vacuum (or dilute with water, basify with 20% NaOH extract with ether in extractor and dry, evaporate in vacuum the... 

The polyethylene film thus obtained was packed in a 100 mesh stainless steel basket, extracted with hot p-xylene in a Soxhlet extractor for 48 hours, washed with acetone for 4 hours in the same type extractor, dried in vacuum for 20 hours at 40°C and weighed. The gel fraction (Gf) of the polymer was detrmined by the equation (2) from the weight change by the extraction. 

Grips, handles for irons, flatware, vacuum cleaners, steam extractors, handheld vacuums and other floor care items, coloured utensil grips. .. 

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