with minimal solids settling application_number US 4468305 A description the inventions described herein are preferably intended to be utilized in advancing the art of high pressure catalytic slurry bed reactor vessels employed in the conversion of fossil fuels particularly coal heavy petroleum oils and tar sands into light hydrocarbons useful as fuels and chemicals these vessels also include the known reactors used in the h oil process the lc fining process the h coal process as well as others as noted herein before the use of ebullating bed catalysis reactor technology is well known to those skilled in the art and the advantages and disadvantages of the reactor technology is well documented in the art the inventions presented herein are intended to advance those advantages and overcome those disadvantages however it will also be apparent to those skilled in the art that the inventions described herein can have useful applications in chemical apparatuses outside the scope of just ebullating bed reactor vessels and may be useful individually or in combination in reactors employed in the petroleum and energy industries such as fixed bed reactors fluid bed reactors slurry bed reactors and the like indeed reactors employed in the chemical industry such as polymerization reactors and hydrogenation reactors and the like are candidates that can benefit from the inventions.