Vacuum frame

If at all possible, a laboratory bench or a table ca. 1 m high should be available at right angles to the vacuum frame, for ancillary equipment such as oscilloscopes, electrical instruments, microcomputers etc. and there should be within easy reach of the operator a bench or table for Dewar vessels, reagents, etc. 

Your next step is to lay the stripped negatives down on a sheet of light sensitive aluminum called a lithographic plate. It is best to have a vacuum frame so the negatives will be pressed uniformly on the plate. Then the plate is exposed to an arc li t for from two to two and a half minutes. 

The dark blue solution containing 5—10% of cellulose with a DP of 1000—2000 is filtered through a series of plate-and-frame filter presses using fine mesh metal screens to remove any particles that might block the spinneret holes. It is then deaerated under vacuum and stored ready for spinning. Unlike viscose dope, the cuprammonium cellulose [9050-09-3] solution is relatively stable. 

Use of ultrafiltration (UF) membranes is becoming increasingly popular for clarification of apple juice. AH particulate matter and cloud is removed, but enzymes pass through the membrane as part of the clarified juice. Thus pasteurization before UF treatment to inactivate enzymes prevents haze formation from enzymatic activity. Retention of flavor volatiles is lower than that using a rack-and-frame press, but higher than that using rotary vacuum precoat-filtration (21). 

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. 

Modules Eveiy module design used in other membrane operations has been tried in peivaporation. One unique requirement is for low hydraulic resistance on the permeate side, since permeate pressure is veiy low (O.I-I Pa). The rule for near-vacuum operation is the bigger the channel, the better the transport. Another unique need is for neat input. The heat of evaporation comes from the liquid, and intermediate heating is usually necessary. Of course economy is always a factor. Plate-and-frame construc tion was the first to be used in large installations, and it continues to be quite important. Some smaller plants use spiral-wound modules, and some membranes can be made as capiUaiy bundles. The capillaiy device with the feed on... 

Depending on the type of filter device, additional requirements may be made of the cloth. For example, in a plate-and-frame press, the sealing properties of cloths are very important. In this case, synthetic cloths are more applicable staple cloths, followed by poly filament and monofilament cloths. In leaf filters operating under vacuum and pressure, the cloth is pulled up onto rigid frames. Since the size of a cloth changes when in contact with the suspension, it should be pretreated to minimize shrinkage. 

Plate and frame e.xchangers (plate heat exchangers)-used for heating and cooling in reactor off-gas quenching, vacuum condensers, desuperheating, and humidification. 

It is the responsibility of the supplying contractor to ensure that the user is aware of the need to clean or replace air filters and knows how to carry this out and when. Spare filters should be available so that the change of clean for dirty can be made in the one operation and the dirty filters taken away in closed bags for cleaning or disposal, to prevent release of dirt in the conditioned area. It is an advantage if the person changing the filters has a hand vacuum cleaner to pick up dirt which may become dislodged, and to clean the filter frames. 

As an electrolyte, Nafion 112 (Du Pont, Inc) membrane was pretreated using H2O2, H2SO4 and deionized water before ion beam bombardment. The prepared membranes with a size of 8 X 8 cm were mounted on a bombardment frame with a window size of 5 x 5 cm, equal to the active area of the test fuel cells, and dried up at 80 C for 2 hr. Then, the mounted membrane was brought in a vacuum chamber equipped with a hollow cathode ion beam source as described in the previous study [1]. Ion dose was measured using a Faraday cup. Ion density... 

In order to outline the main features of measuring the gravitational field with the help of ballistic gravimeter imagine that a small body falls inside a vacuum cylinder under the action of the gravitational field only. In accordance with Newton s second law in the inertial frame we have... 

Batch vacuum leaf Batch nutsche Batch pressure filters Plate and frame Vertical leaf Horizontal plate Cartridge edge... 

Both characteristic X-ray line and continuous spectra were used to evaluate the performances of the resists. To determine exposure parameters (i.e. sensitivity and contrast) irradiations were carried gut in this study using the aluminum Kot- 2 emission line at 8.3t A generated by means of a modified Vacuum Generators Limited model EG-2 electron beam evaporation gun. The resist samples were exposed through a mask (A) consisting of a range of aluminum foils of different thicknesses supported on an absorbing nickel frame in order to vary the X-ray flux. 

There are a variety of arrangements that operate in the same manner as the plate- and-frame filter. One is the leaf filter, which may consist of one or more frames that are covered by the filter medium and immersed in the slurry. These filtration devices, are often operated by means of a vacuum that draws the filtrate through the filter, with the cake collecting on the filter medium on the outside of the frame. 

A slurry is being filtered at a net rate of 10,000 gal/day by a plate and frame filter with 15 frames, with an active filtering area of 1.5 ft2 per frame, fed by a positive displacement pump. The pressure drop varies from 2 psi at start-up to 25 psi after 10 min, at which time it is shut down for cleanup. It takes 10 min to disassemble, clean out, and reassemble the filter. Your boss decides that it would be more economical to replace this filter with a rotary drum filter using the same filter medium. The rotary filter operates at a vacuum of 200 mmHg with 30% of its surface submerged and rotates at a rate of 5 min/rev. If the drum length is equal to its diameter, how big should it be ... 

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