INVENTIONS IN FILTRATION AND SEPARATION

Abstracts of recent British Patents

Screening machine Ill GB 2276339 Buehler AG descr ibes a ~creening machine. In a final screening ,~here small a m o u n t s of coarse solids are ~ ,para ted from flour, a p n e u m a t i c con- ,'eyor feeds the flour to the inside of a il xcd cylindrical screen, inside which a set Jl axial ba r s rotates . These carry axially

~paced e l a s t o m e r i c lobes w h i c h j u s t ,:',~ntact the screen. The lobes are stag- ~ered from one ba r to the nex t a long helical lines, and serve to sweep coarse ~,)li(ls axially to an outlet, and to keep the l]oor rota t ing inside a screen unti l it passes t h r o u g h to a hopper . The ro to r includes baffles and a feed screw. A hous ing enclosing the screw is ro ta tab le ,q the main hous ing to set the inlet at a , ,nvenien t angle. An elastic disc shie lds

h e outlet, and acts as a d ischarge valve. ('~ fi~tres, 3000 words)

Continuous separation of immiscible liquids

h~ GB 2276561 Squid Sys tems Pty Ltd l e sc r ibes the c o n t i n u o u s s epa ra t i on of ~mmiscible liquids. Sludge on the floor of t~L oil s torage t ank is b roken up by je t s of tl~)t wa t e r delivered by a t racked robot. I'he resul t ing m i x t u r e of oil, solids and ,~ater is d rawn into a vessel and then fed ~ a separa t ion tank. The m i x t u r e en te r s h e t ank ' s first c h a m b e r and sepa ra t e s ~ n d e r gravity. The oil f lows over a ,~rtically ad jus tab le weir into a n o t h e r , hamber , while the w a t e r flows t h r o u g h he h)wer out le t to the thi rd chamber , and hen over a weir to the lour th chamber .

";,,tried solids are removed f rom the first -hamber by a chain sc rape r to the outlet ,

m d reduced to a cake in a centr i fuge or h~canter. The sepa ra t ed oil and wa te r are dso purif ied using centrifuges, wi th the

~ a t e r being recycled to a robot. Some of h e s t a g e s a re s t e a m - h e a t e d . S ludge '~-eakup may be ass is ted wi th chemicals t o m a tank. (4 figures, 3750 words)

Apparatus for filtering cuttings from drilling fluid

:ll GB 2276562 W. Woodburn descr ibes m a p p a r a t u s for filtering cu t t ings f rom drill ing fluid. It compr i ses a filter fitted in m endless recirculat ing loop as the inlet i(w receiving drilling fluid and cut t ings Jrom a drill ing well, and fitted so as to ,lirect the drill ing fluid and cut t ings on to t he filter. An out le t is fitted to receive the filtered drill ing fluid f rom the filter, in o rder to supp ly the filtered drill ing fluid I(, a drilling well. (1 figure, 1000 words)

Face mask filter mounting In GB 2276565 JSP Ltd descr ibes a face m a s k filter moun t ing . A bos~ wi th a

Filtration & Separation February 1995

central pa s sageway is carr ied by a disc m e m b e r , a n d is p u s h e d t h r o u g h an open ing provided in a face mask. It is screwed or o therwise fit ted into a ho lder which ho lds a r e sp i ra to ry filter mem- brane, or which fo rms pa r t of a respi ra- tory filter. To enable the ho lder to be connec ted to m a s k s wi th open ings of va r i ous sizes, an O-r ing loca tes in a groove a r o u n d the boss and engages in an opening. O-rings of varying sizes can be p r o v i d e d for l oca t ing w i t h i n the groove, depend ing on the size of the open ing in the face mask. If the open ing has a d i ame te r close to t ha t of the groove, the O-ring can be omit ted. When the face m a s k is p r ope r ly sea t ed on the disc m e m b e r and the holder is screwed into place, the mask is c l amped between the disc m e m b e r and the holder.

Demountable filter In GB 2276835 Finn-Fi l ter Oy descr ibes a d e m o u n t a b l e filter. It compr i ses a gen- erally f rus to conical fi l ter sleeve w i th axia l p lea t s , t he e n d s of wh ich a re c lamped be tween inner and ou te r par t s , wi th m a t ch ing edges profiled to the s h a p e of the pleats, i.e. with tee th which are ax ia l ly inc l ined. N u t s on a rod a re t igh tened to p u s h the ou te r p a r t s to- w a r d s each other, in o rder to grip t he ends of the sleeve aga ins t the inne r par ts . (2 figures, 1500 words)

Removal of metal particles from drilling mud

In GB 2277044 OED In te rna t iona l Ltd descr ibes the removal of meta l par t ic les f rom drill ing mud. Swarf is removed f rom drilling m u d by ou tward flow fi l t rat ion t h r o u g h at least one filter d r u m ro ta t ing abou t an inclined axis. Mud is fed into the inner d rum, and flows t h r o u g h perfora- t ions and then t h r o u g h an ou te r d r u m with a f iner ape r t u r e size. The d r u m s are independen t ly driven at var iable speeds, e i ther in the s ame or oppos i t e direct ions. A blade be tween the d r u m s cuts off any sward pieces t ha t are project ing t h r o u g h the perforat ions . The s w a g is d i scharged into a con ta ine r f rom the lower end of the d r u m s , t h e i n c l i n a t i o n of w h i c h is adjustable . The fil tered m u d may be fed to a tank, f rom which it overflows as a th in s t r e a m down an inclined plate, and where a moving magne t ic belt picks up any remain ing meta l part icles. (5figures, 2000 words)

Separation of condensate from air

In GB 2277~57 Leobersdorfer Maschi- nenfabr ik AG descr ibes the sepa ra t ion of c o n d e n s a t e f rom air. C o m p r e s s e d a i r

p r o d u c e d in a m u l t i s t a g e c o m p r e s s o r ins ta l la t ion is cooled in h e a t - e x c h a n g e r s c o m b i n e d wi th c o n d e n s a t e s e p a r a t o r s af ter the c o m p r e s s o r s tages and fed to a c o n s u m e r , in o r d e r to s e p a r a t e o u t c o n d e n s a t e f rom th i s air, t he a i r is cooled in the last h e a t - e x c h a n g e r com- bined wi th a condensa t e s e p a r a t o r to a t e m p e r a t u r e which lies below the tem- p e r a t u r e to be expec ted at the consumer . (2 figures, 2000 words)

Filters and filter manufacture In GB 2277458 Pall C o r p o r a t i o n de- scr ibes a filter of p lea ted shape. It is formed f rom a p o r o u s meta l shee t filter medium, which is cut into s t r ips and then connec ted edge- to-edge by welding to form V-shaped pleats , wi th the welds forming ridges on a l te rna te ly oppos i te sides of the filter. This has significant benefi ts over cor ruga t ing the sheet by bending, including an absence of crack ing, and so gives a significantly be t t e r fi l ter p e g o r m a n c e . The fil ter may be g e n e r a l l y f lat or t u b u l a r . The f i l t e r m e d i u m may be s in tered s ta inless-s teel fibres, l amina ted wi th a second layer of s ta inless-s teel woven m e s h wi th s in tered s ta in less-s tee l p o w d e r in the interst ices. (2figures, 3000 worc£s)

Centrifugal separator In GB 2277700 Kyffhauser Maschinenfab- rik Ar tern GmbH descr ibes a centr ifugal s e p a r a t o r wi th full-load s tar t ing. It com- p r i s e s a h o u s i n g e n c l o s i n g a r o t a r y s e p a r a t o r d r u m and a drive motor , the ro to r of which is directly and rigidly connec ted to the d r u m by a driveshaft . The d r u m , r o t o r a n d s h a f t f o r m a ro ta t iona l sys tem which is non-resi l ient ly m o u n t e d by bear ings in a s t a to r of the motor . The s t a t o r is rigidly a t t ached to a b e a r i n g s u p p o r t l o c a t e d on a level be tween the d r u m and the motor , and c o n n e c t e d to the h o u s i n g by way of res i l ien t e l e m e n t s which radial ly and ax ia l ly loca te t he r o t a t i o n a l s y s t e m relative to the housing, bu t which p e rmi t osci l lat ion resul t ing from, for example , d r u m imbalance.

In one vers ion the ro ta t iona l sfrstem is solely s u p p o r t e d by e lements , bu t the shaf t can also ex tend d o w n w a r d s from the motor , and be s u p p o r t e d non-resil i- ently from the hous ing in a m a n n e r which p e r m i t s r o t a t i o n and osci l la t ion. The d r u m may be m o u n t e d directly on the m o t o r shaft , or on a rigidly secured extens ion. (4 fi!lures, 2750 words) []

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