Next generation candle gap filter for brewers

In this article Dr Hans Westner, KHS AG, Germany, explains why the Getra EC0 candle gapfilter

is a sipijkant

filtration equipmentfor

the brewing industry.

Generation Candle Filter for Brewers

Ne;rt

C-P

T

advancement in

he art of brewing has been around

candles, which had a gap width of approxi-

for many thousands of years i

mately 60 urn, and later by spiral wire can-

evi-

dence exists that the Chinese

dles. The spirals were mechanically

.

a simplified handling during installation and maintenance.

brewed a beer called Kui approximately

wrapped around a centre profile rod, cre-

Service Life

5000 year ago, and it remains one of the

ating a defined constant gap width of 50-60

The filter candle is the heart of any candle

most popular beverages

urn. Today, the slit tube candle is the most

filter system; therefore,

commonly

placed on optimising

world. The production

in the Western of beer involves a

number of key steps, with the fermenta-

used filter candle design.

Filter aids such as kieselguhr,

great emphasis was

the Getra ECO’s

design. In addition to changing the stainless

which is

tion stage obviously being the most

the fossilised remains of single-celled

steel candle’s outer dimensions

important.

organisms,

in the filter matrix,

However,

after fermentation

beer contains a high percentage

of sus-

pended solids such as yeast, bacteria ,

and

precipitated

proteins,

all of which need to

be filtered

out. Despite

the growing use

of membranes,

the pre-coated

candle fil-

ter remains one of the most commonly used filtration

system in the brewing

industry. Candle filters comprise

a number of

rod-shaped filter candles, the design of

are also routinely

enhance filtration.

added to

Kieselguhr

functions in

two ways: to form a precoat on the surface of the filter candle, protecting plugging; and to flocculate

reduced to 30 urn; 40% smaller than the standard slit tube candles, The new candle design also increases

it from

the surface loading of kieselguhr

and coalesce

very fine materials that would otherwise

be

of this for breweries

difficult to filter.

Cetra EC0 In collaboration

be filtered

prior to re-cleaning

GmbH, Germany, KHS developed the

preparing

process. The greater

slit tube can-

also produces

disc candles. They consisted of a support

contributes

spacing toes, and had a smooth surface and

advantages: . a longer operating life; . a lower total kieselguhr

defined gap widths of 80um.

.

kieselguhr

a minimum

capacity

specific filtering

surface area of 0.2 m2 per candle, which consumption;

a reduced water consumption cleaning; and

and

the filter for the next filtration

Getra ECO, a new generation

replaced by slit tube

of

in the

work effort because larger batches can with Schenk Filterbau

dle gap filter system with the following

were subsequently

impact

is an extension

filter cycles and thus a reduction

which has varied over the years (Figure 1).

Disc candles

by 50%,

i.e. from 6kg/m2 to 9 kg/m*.The

The first filtration systems were fitted with rod upon which lamina were fastened with

and spacing

the gap widths were

during

to reducing

candles required

the number

for a particular

of

candle

filter. The Getra EC0 infeed distributor

also possesses a new for the unfiltered

uct at the tank intake. It promotes homogenous throughout

cross and laminar flows the entire candle matrix,

guaranteeing kieselguhr

prodthe

good distribution

thus

of the

over the filter elements,

as well

as a minimum mixing phase.

Water

Savings

After completing

the filtration

essential that residual kieselguhr

process it is on the

candles, tank walls and the underside of the candle plate is properly removed prior to the next filtration

process. In the past

this involved flooding the whole tank with water twice. To avoid this the Getra EC0 has a specially integrated

system of spray

nozzles in the filtrate zone beneath the distance plate. Controlled distribution

22

September

2000

flows with directed

and aimed spraying ensure that

Filtration+Separation

water is applied effectively to all surfaces to be cleaned. The major benefit of this system is that water consumption

of the system is signifi-

cantly reduced. For example, in a filter with a capacity of 250 hectolitre

(hl) per hour

and a total tank volume of 65 hl, the costs of using 120 hl of water and the disposal costs of the resulting sewage are avoided. Backwashing contributes

of the filter elements

also

to the lower water consump-

tion (Figure 2). A specially designed, patented stainless steel intake distributor on the candle filter head in the filtrate zone provides directed and controlled flows during this process.

water

Specially mould-

ed channels control the volume of water and the flow is conducted

so that an inten-

Candle Filter System A candle filter system comprises dro-conical unfiltered

product

trate collection

space. The cylindro-coni-

of the tank encloses

tered product

pension during pre-coating

filter

candles are suspended in the intermediate plate. The filtering

area of each filter ele-

ment ranges between

sus-

0.1-0.2

m2, and a

single candle filter system can contain

and filtration,

several hundred filter candles depending on the size and capacity of the filter.

even application

The unfiltered

beer

Then a further

of the air means that the

Kieselguhr project

reduction kieselguhr.

g of kieselguhr

is

process.

Use

In contrast, aims of the Getra

in the overall consumption two-step

is forced into the filters. The desired clean-

ing is the standard procedure.

ing action on the filter elements

of kieselguhr

of

only one kieselguhr

The dosage

pre-coating

the nominal filter surface; 700 g the

uniform formation

minimum

mixture

and one pre-

coating process, i.e. the total volume of kieselguhr

in the first and second

shape design of the candle gap. The

filter candle ele-

ment makes it possible to operate with

pre-coat-

duced by the jetting effect of the wedge-

the smaller, exactly defined

gap size of the Getra EC0

was to achieve a significant Currently,

50-150

added per hl of beer during the filtration

entire length of the candle is cleaned.

soon as this film of water extends over the

,

designed dis-

device. The rod-shaped

during clean-out.

entire length of the elements,

film and

tribution

and receive and discharge the sediment

EC0

of the trickle

of

are conveyed against the gravi-

means of a correspondingly

the u&l-

the kieselguhr

enters at the

cone. The particles

tational force onto the filter surface by

area where the conical part

is used to distribute

the inner walls of the filter elements.

is pro-

kieselguhr

head located above

plate serves as the El-

One of the important

a blast of air

tip of the container

the intermediate

sive cleaning trickle film is produced on As

and

areas separated by a

plate. A torospherical

cal section

dosed with the kieselguhr

a cylin-

tank with the filtered

required is decreased by a por-

tion of the amount required for the second

steps averages 1000 g/m2 of

pre-coating

step.There

is also the addition-

al benefit of simplifying the material han-

and 1500 g the maximum.

dling, i.e. less kieselguhr 1

to be procured

and stored.

Quick-fit

System

The candle headpiece has been redesigned

so that filter element installation and maintenance is easier. In the past, candle heads were equipped with threads and were manually screwed into the candle plate, making installation example,

a labour-intensive

process. For

a 250 hi/h capacity filter, with an

average of eight candles per m2 of filter surface would contain 400 candles, all of which would have to be installed manually. The new candle head is equipped a ‘quick-action,

quarter-turn’

that makes installation ter elements

with

fastener

and removal of fil-

quick and easy. One person

is able to install the filter candles by simply pushing and turning them in the candle plate. The candle head also simplifies servicing. The insides of candles require occasional

cleaning with a high-pressure

spray. In the Getra EC0 achieved without

this can be

removing

the elements

because the open inner filtrate the filter candle leads directly

,; ,’ ;e :- ‘,~;‘L&~,‘i, . r’: * ; ‘~~~~~~~~~~ 1,-‘l; , ,: ,>‘I. c*:; ; ,’ ,,:..::f, up”“:” , 8,,,‘,.):’, :

space of through

the free opening in the headpiece filtrate

into the

area.

Directed

Venting

Preventing the intake of oxygen is an important factor in achieving good filtration results, thus proper tank venting prior to the filtration process is important.

Filtration+Separation

September

In the Getra

2000

23

r

.

CO, content:

fluctuation

< 0.05 % of

the specified standard. Output

l

250 hi/h.

Samson had the choice of horizontal screens or vertical candles for holding the kieselguhr

:

mixture,

the Getra EC0

and decided to trial

candle filter system. The

filtration plant (Figure 3) was composed

of

the following units: Filter tank and Getra EC0

l

Kieselguhr

l

filter candles

dosing container

with pre-

coating and dosing pump Beer supply pump with complete piping

l

Turbidimeter

l

at the filter outlet

The new filter cellar has been in operation since the beginning of the year and has achieved the following parameters: EC0

system the tank is pre-vented via the

exporting

spray nozzle system. In addition, air can be

to countries

such as Germany,

l

Austria and the USA.

bled through an air venting system located

The brewery was searching for a new

l

on the opposite sides of the tank at the high-

filtration plant that could be custom-

l

est point of the unfiltered product area.

designed and would satisfy strict interna-

l

tional standards. The filtration

l

Getra EC0 in Action

specifications

Founded back in 1795 the Samson has been part of the Group of

Southern

Bohemian

1992. Its current

l

since

output is 500 000

hi/year, and has an export

performance

3000 hl per

l

90’ turbidity

0.16 EBC

Total kieselguhr consumption

103 g/h1

Maximum pressure increase: - 0.1 bar/h Time required for cleaning with cold water

yeast-free

0.4 EBC

25’ turbidity:

10 minutes

product.

Republic,

Breweries

system’s

were as follows:

To produce a practically

l

Brewery in eskk Bud jovice, The Czech

Filtration batch.

l

rate of 5%,

A maximum pressure difference

Forfurther @motion

0.2 bar/h.

Maschmen und Anlagenbau AG,Juchostr+

contact: Dr HonsCVestner, KHS

Turbidity < 0.5 EBC (90’ turbidity

Dorrmund. Germany.Zl. +49 231 i690

measurement).

231 S69 1541; E-mail: westn~~.hhuns@d~.khs-ag.com

20,43143 Fax: i49

Filtration+Separation Prod~uct Achievement Awawls 2000 In the

July/August

issue

of

Filtration+Separation

we pub-

lished the shortlist

of compa-

nies

nominated

for

Filtration+Separation Achievement p.30-34

the

Product

Awards 2000 (see

for

details).

There

September

18

2000

to

25

September 2000. Voting

The completed be returned

is simple.

All you

attention

form should

marked

for

have to do is tick ONE product

no later than 25 SEPTEMBER

of your choice

2000.

in EACH

gory on the voting opposite

cate-

form

(see

page) and nominate

a

the

of Heather Johnstone

it can be sent either

by

mail to:

Awards Dinaer The

Achievement

Dinner

and

take

Filtration

PRODUCT

OF THE YEAR,

Elsevier AdvancedTech-

held

and

qualify

nology

from

had been market

launched within

the

onto

the

last

two

years.

you’ll

thank

you to all the readers

chance of winning vouchers up

PO Box 150 Kidlington,

from

Industrial

publica-

Engineering

pleted

Filtration

response nal.

has been

However,

haven’t

voted

if

-

the

you

and would

Industrial

Mem-

of

still

branes’

; ‘Handbook

like

media’;

and ‘Filtration:

ment

line has been

Process Simulation’.

24

September

from

2000

and

‘Hand-

to there is still time. The deadextended

‘Filters

Handbook’;

book

phenome-

Elsevier range of

tions that include:

forms

off any

AdvancedTechnology’s

who have already sent in comvoting

the

to the value of US$400 products

We would like to say a big

for

Selection

of Filter Equip-

Modelling

and

2000

in

held

Conference which is being USA,

November.

is welcome

to the dinner,

UK

will INDA’s

Philadelphia, 28-30

Everyone Oxford

Awards

Ceremony during

and Exhibition,

each comprising

that

place

Filtrationfseparation

were a total of ten categories, products

Filtration+Separation

Product

on

the

to come

which

will

be

of

29

evening

November. or faxed to +44 The entries

first

1865 843971.

three

completed

Further details on how to attend can

drawn out of a hat will

win a prize (1 st = $400,2nd

=

$300 and 3rd = $200 worth of vouchers). Keep the voting forms coming in!

be obtained by contacting Champney

Caroline

at the

Filtration-i-SeparationO$ice: Tel: +44 1865 843190; Fax: +44 1865 843971; E-mail: [email protected]

Filtration+Separation