Sintered metal filters benefit from asymmetric design

In this article

GmbH, reports sintered

cartridge

Metals

study between

and thereby

improve

of the filter

Filters

a standard membrane

wall configuration.

design is said to prevent _

operation,

Sintered

and its latest metal

that has an asymmetric

asymmetric during

on a comparison

metalfilter

filter

ofGKiV

Peter Neumann

The

a high pressure the cleaning

drop

ejjiciency

backJlush,

Sintered metal filters benefit f ram asymmetric design

S

tructures

formed

ing of metal bronze

by the sintcr-

powders

or stainless

solid components tain interconnected

such as

the years this porositv

metal

steel into naturally

con-

pores.

Over

has proved

Iy useful in the field of filtration. filter elrments

vcssfully

in industrial

tate high strength

cxtrcmcSintered

c.hcmical\

and tcmpcraturc.

legislation

drmanding

tnxironmcntal

the rcc \ cling 01

ha\ c Iwcn used \uc-

cleaning

applications

their dispo<;al, has also hrlpl

and resistance

that die-

of filter element\,

the USC‘ of thcsc

to both

Howcvrr,

rather

than

to promote

fiIter_ elements.

as \z ith all technologies,

metal filters have their limitations.

hintcrcd For exam

plr, because sintr stainlc55 steel liltcr cartridges 2

hake a IvaIl thic knw

3 mm they csperience

prrhsurr

a comparably

ofthe filtw.

to provide sufticicnt

anical strength,

but is not essrntial

hccausc th c \c [,aration

rctcntion

a coarw

u hich i\ the support filtrr

material,

support

lx axial prrssing

tric5 and iw\tatic. tridges.Thc

strut

powder, an<1 a thin

ptxwinq

labcr,

procc‘ss,

onto the support

ii then (luring

I’igurc

I shox\-5 a

of the aaxmmctric

structure.

process.

mic-rograph

IS pro-

for filter carmcrnbraw

in a scparatc

bonded

thr sintcring

mater-ial

for plate gcomc-

thin metallic

~1hich is madc diffusion

metal

la>vr (< LOO l(m) made frr~m

the \amc allo\.‘l’hc duwd

SIK.4 -K .44

is a po\~tlct-/~~o\~(Icr

turn, comprising

atti\v

of partic,lc:.

of the filter mc(lia

d
(Aswnmctric)

mc~h for pat-tick

ofa mlllimetrc.

within the first tenths ‘l-he nc\\l\

01.

l.he wall thick-

ncs5 is rcquircd

takes place on the surf&c

7

high

drop that dccrc~ax5 the cfficivnc7

the back flushing

Symmetric

ofbct\\ccn

Characteristics It i\ not surprising that a\vmmetricall\ dcsigncd

metallic

cnt propcrtics metric)

26

July/August

2000

sintered

mt’m1xanc.s

from con\cntional metal

haw tiillcr(avn-

filter\.

Filtration+Separation

Figure

the difference

the pressure function

drop

in

during

pressure

filtration

asymmetrical element

back flushing

distribution

IS)

??

to

IS had a

pore size of 4.5

a tighter

do not

The grade

carbide

data (Figure

I

cycles,

increase

a filter

drop

to remow

In order

to gain a more

Ho\ve\rr,

accurate

picture

for the SIKA-R

performance R AS under

-e-SIKA-R 10IS,limestone

operating

ditions

-m- SIKA-R 3 AS,

100

gas filtration

the surface

decrease

layer

test in filtration

with bo1.h elements.

the beginning

the lime stone

IS

tests

AS were

and end values consistently

test (Figure

cant difference

with VDI

seen.

high-

IS. For

6b) a signifi-

3926 recommendations

the filtration

were carried

seconds,

out. Two dif-

in the filtration

Follobving

time

100 bat k flushing

\sas

cl clcs

time for the SIKrZ-R IS xvas 4

while

the S1K.VR AS had a time

SIKA-R AS

alumina

1.73

mg/m3

1.08

mg/m3

Lime stone

0.224

mg/m3

0.025

mg/m’

Filtration+Separation

a certain

and back flushing

er than the \-alucs of the SIKA-R

con

IS.

to the time

In the alumina

ha), a strong

this sta-

I

in accordance

SIKA-R

of the SIKA-

lwfore

is reached

time occurred

\vas

than the SIKH-R

cvclc time, relates

Operational performance

(Figure

pressure operations.

.AS reaches

quicker

100

that a dra-

in ongoing

1s in operation

is performed

after

meaning

the SIKr\-R

greater

that the pro

of the residual

to occur

pressures

of the

differ

The curkcs

a stable condition

on the element.

b

of the

grn-

Filtration

retention.

drop

in both tests indicate

SIK.4.R AS exhibited particle

drop

as

However,

3), the

prcssurc

faster than that of the

and the pressure

ble conditions

from the pore size distri

and back flush-

high than at the beginning.

unlikely

as the

the

of the two

ence at the end of the tests was twice

matic

using

test dust. As expected

bution

the residual

back flushing

the single pass method, with silicon

the filtration

ccss reached

efficiencv

types \vas measured

Iluring

erated

4) of both filter

AS xvas lower

IS, reflecting

in the bvall structure

SIK.&R.\S,

do not penc-

of both tests the

of the SIKh-R

SIK.i\-R IS increased

it over the time.

(Figure

difference

ing cydes

pdrc

means

as far into the filter,

block

drop

drop o\cr

of back tlushing

At the beginning

filters.

to surface

and therefore

100

5 shobvs the pressure

the filter as a function

3).

and

cfficicnc\.

than that of the SIKA-R

that particles

80

total collection

\vhile the SIKA-R

size distribution

60

.

ocles.

trate

40

cvclc time;

pressure

filtration,

Numberofbackflaohingcy(es

filtration

clean gas dust concentration;

SIK.-\-R AS had a maxi-

urn. In relation

20

of cat h filter \vas

mum pore size of 2.5 urn,

maximum

I

of 5 g/m<

.

Figures

pore size (Figure

Jverc

assessed b!- comparing: . residual pressure drop after regeneration;

to the

membrane

have a tighter

filter,

cfficienc\

were a cgas and a dust con

180 m/h

(cfccd)

The performance

AS) was found

element

metal

test parameter\

(vf) of

centratilm

the

sintered

the metallic (SIKA-R

wlocitv

that it is

filter (SIKA-R

mcmbranc

sintered

flow rate properties,

compared.The

step.

conventional metal

and similar

of the

In comparison

metallic

,-\s above an

with tht same total collection

drop

to clean during

x\-hich is a

material.

and a comentional

membrane

means

easier

and lime stone,

good agglomerating asymmetrical

as a

of wall thickness.

The lower

particle size [pm]

ating material

2 schematicall>

highlights

July/August

2000

27

.__

I

a

SIKA-R AS

the comentional

+SIKA-R 10IS

reduced

cartridge.

+

centration

SIKA-R 3 AS

the conof alu

the recovery

100

of catalyst

used in

particles,

an im-

37% and the lime

portant

In the past, comcntional

sintered

compared

tcrs had to be cleaned

in an cxtcrnal

to

step in many chemical

IS.

ccss cwry

four weeks because

The total col-

Following

the installation

efficiency

of both filters 60

filter

stone hv 10 fold

lcction 60

metal

To date it has been successfully

mina in the gas b!

SIKA-R

40

sintcred

dctcrmined

was

to be

processes,

of clogging,

was able to operate

6-S months

before

an external

was required.

fil

pro

of the SIKA-R AS

the process

process

metal

for up to cleaning

In addition,

after

Number of back flashing cyles

1OO%, meaning particles

all

cleaning

the filters

Although

this studv

performance

II

300

tion application

In summary

membrane

200

the

asvmmetric

filtration

t P 100 &

.

0 40

60

Number of back flashing cyles

tion.

mem-

brane showed

a

perfor-

tries,

mance

in rcgcner-

cess fluids.

pressure

drop and

contaminate

cleaned

conin the

gas than

The Reader Enquiry for this advertisement

July/August

2000

at applications

and water

for liquid

such as cake filtra-

treatment

as well as in the treatment

in the food indusof pro

ation, residual

centration

28

It is aimed

ASmetallic

is also suitable

applications

at the

in an air filtra-

the SIKA-R

filter

and beverage

better

only looked

of the filter

Conclusions

metallic

E x

be re-installed

and used again.

were

retained.

j

could

Forjiurther mformatmn contact:

Peterh’eumonn,

GKk S~nterMetals Filters GmbH, DahllenstraJe 13, D-42477 Radevormwld, German,t: 51: +19 2195 6090; Fax Jr49 2195 ti0918

is 521

Filtration+Separation