Chapter 3 Functional descriptions
SMSO-2-02.03- 15.07.03 51
3.2.15 Screw connections / pipes / hoses
All water dosing, preparation and control components are
connected to a wide range of pipes, hoses, and connection
materials. At first glance, the range used appears to be rela-
tively confusing, but each screw fitting and each pipe has
been carefully selected for the purpose for which it is intended.
This complex connection system contains a number of possi-
ble sources of faults, which can result in leaks and in a low
quality of product. For these reason it is necessary to ensure
that a series of working rules are observed. You will find de-
tailed technical data relating to pipes and screw fittings in the
spare parts catalogue, under the section entitled “Screw fit-
tings”
The list below contains just the basic working rules that must
always be observed when carrying out maintenance work.
Material properties
Replace defective pipes only with components having
identical material properties, in particular:
The material used for coffee pipes must be acid-resistant.
Hot water and steam pipes must be permitted for the
relevant temperatures.
Only silicon tubes for use in food applications must be
used for milk products .Ensure that different metals in
contact with one another under the effects of certain
ingredients of the fluid media are not subject to electro-
chemical corrosion , resulting in decomposition. Therefore
use only the original material pairings used.
Observe the fitting instructions for the various types of
material.
Design characteristics
Baffles, filters, or nozzles are fitted inside some screw
fittings. The functional safety of these elements can be
assured only if they are installed into the screw fittings
with the correct dimensions.
You must not replace the specified components with
components possessing different thread types and
nominal values. (Interchangeability / compatibility)
The nominal values , of pipe materials , must not be
changed to other values (this could have a negative effect
on the thermal stability of systems, time-dependent
processes, functional safety of the devices).
Pliable plastic pipes must be fitted into screwed fittings
with support bushing.
Take note of the bending radius of pipes, hoses and
tubes. Teflon pipes tend to kink or break if the bending
radius is too small.
Depending on the unit, hoses with a smooth internal wall
should be used for wastewater and disposal pipes.
Screw fittings with Loctite coating
A large number of screw fittings are coated with a sealing
compound When these screw fittings are used, it is
essential that the following working rules are observed:
Do not treat screw fittings as bulk items. (the coating can
be chipped off or damaged)
Protect the coating from contamination (chips, etc.)
After fitting the position (angle) can be changed for a
maximum of 24 hours.
The screw fittings are watertight immediately after fitting.
After dismantling, the coated parts must be cleaned and
wound round with Teflon tape before refitting. The Loctite
coating is designed for one-off use.
Water tightness
Cylinder head threads are not sealed with Teflon tape.
When using Teflon tape make sure that it is not applied
over the edge of the thread. When unscrewed, this tape
could shear off and get into the water system, or reduce
the cross-section of the pipe!
Greasing the screw fittings
If screw fittings (such as feed pipes / temperature sensor
on the instant heater/steam generator) need to be
greased with grease for food applications, this must be
applied very carefully. Make sure that the grease cannot
get inside the pipes as this would make the water taste of
grease.
Maintenance
All pipe sections should be checked periodically and replaced
depending on their condition or on the service instructions
(see section entitled “Service instructions” and the tables it
contains).
Service intervals
After every 45,000 coffee servings or after 12 months of op-
eration check the following:
Visual check for calcium deposits, damage, dirt and seal
for all pipes (including screw fittings).
After 36 months of operation, replace:
The service instructions indicate the pipes that must be
subject to special checks at specific intervals.
Drawing symbol
Illustration
To Next Page
Loading...
Need help?
General
