Vacuum frame units

ER E discussions with Texaco and with Shell on bottoms processing are summarized herein. Texaco has indicated that its partial oxidation process could be applied to coal liquefaction bottoms on a commercial scale and that operation of their 12 T/D pilot plant with coal liquefaction bottoms representative of a projected commercial feedstock would be adequate to set the design basis for a commercial facility. Texaco indicated that three to four years after successful operation of the 12 T/D unit a commercial facility could be ready for startup. In initial discussions, Shell has indicated that development of the Shell/ Koppers partial oxidation process for coal liquefaction bottoms would involve operations of both their 6 T/D pilot plant and their 150 T/D demonstration unit. It was estimated that the 150 T/D facility might become available in the late 1980/early 1981 time frame for possible operation on vacuum bottoms. 

Vacuum filtration and screen-bowl centrifuges are the principal unit operations used for mechanical dewatering of fine coal. Pressure filtration (plate and frame filter presses and continuous belt filter presses) is used to a much lesser extent to dewater fine... 

The hltration medium may be made of perforated plates, septum of woven materials, or of granular materials such as sand. Thus, according to the medium used, hlters may also be classihed as perforated plate, woven septum, or granular filters. The hltration medium of the microstrainer menhoned above is of perforated plate. The hlter media used in plate-and-frame presses and vacuum hlters are of woven materials. These units are discussed later. 

To this frame are attached a vacuum manifold to effect the various operations, traps to protect the pumping system, pressure-measuring equipment, and the pumping system itself. In this way, the final vacuum line is a self-contained unit by which all operations dealing with... 

Place the gel carefully on the membrane (no air bubbles) so that the gel and mask overlap by at least 2 mm and fit the top frame. Small cracks in the gel should be repaired with molten agarose. Switch on the vacuum pump (trap between the blotting unit and the pump to avoid solutions reaching the pump) and adjust to SO mbar. Note that all solutions should be ready since the gel is covered with solutions whenever the vacuum is on. 

Fig. 2.56. A skin packaging machine using inhibited polymer films (1) base, (2) vacuum chuck, (3) pallet, (4) heater, (5) substrate film, (6) packed articles, (7) and (8) frames for film fastening, (9) film feeding unit, (10) film, (11) needle roller, (12) Cl vessel, (13) Cl applicator castor...

These basic units—i.e., heater, mold-mounting table, sheet-clamping frame, and vacuum or pressure sources—are contained in every piece of thermoforming equipment however, for highspeed continuous production, many improvements have been made. 

There is also a much more compact and low-cost option - based on the pump manufacturer concept . This concept has been tried and tested for decades in oil-lubricated rotary piston vacuum pumps - so why not in LRVPs. There is no need for extensive frame constructions for mounting system components. Costintensive pipes required for manufacturing previous units, as well as throughout the service life, are no longer required. Components can be retrofitted easily. 

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