ldm partially filled - stebatec€¦ · the ldm is a calibrated measuring device for backflow-free...

Technical information

LDM partially filled (Laufzeitdifferenz-DurchflussMessung)

Between-flange flow meter for partially filled pipelines uses

ultrasonic transit time difference measurement for water

and wastewater applications

(Version 03/2020)

STEBATEC AG, Mattenstrasse 6a, CH-2555 Brügg, Tel.: +41 32 373 15 71 Version 03/2020 of 41

Copyright © March 2020 STEBATEC AG

Any reproduction of this "Technical Information" requires the consent of STEBATEC AG. All

rights to this documentation and to the devices are owned by STEBATEC AG in Brügg, Switzer-

land.


Content

1 Preliminary remark 5

2 Product features 6

2.1 The partially filled LDM – brief description 6

2.2 Application areas 7

2.3 Structure 8

2.4 Properties 11

2.5 Device versions 11

3 Scope of delivery 12

4 Technical specifications measuring sensor 13

4.1 Dimensions and weights 15

4.2 Measurement accuracy 16

4.3 Minimum levels and flow rates 17

5 Technical specifications transmitter 18

5.1 Dimensions and weights 19

5.2 Materials and electrical connections 21

5.3 Operating conditions 23

6 Installation conditions 24

6.1 Pipe cross-sections 24

6.2 Inlet and outlet side of the measuring tube 24

6.3 Inlet and outlet section 25

6.4 Installation before control valve 26

6.5 Pipe gradient 27

6.6 Free outlet 28

6.7 Spacing of the LDM above ground 29

6.8 Minimum bending radius cable outlet 29

6.9 Mounting the transmitter 30

6.10 Grounding 30

6.11 Vibrations 31

6.12 Flange offset of the axes of the pipes 32

6.13 Lateral offset of the pipes 33

6.14 Mounting position 33


6.15 Opening for cleaning 34

6.16 Mounting under difficult installation conditions 35

7 Installation 37

7.1 Fixing 37

7.2 Parameterization 38

8 Maintenance 39

8.1 Cleaning the LDM 39

8.2 Removal and installation 39

8.3 Recommissioning and function check 40

8.4 Maintenance of value 40

9 Contact 41


1 Preliminary remark

! Caution

This technical information is not a substitute for an operating manual. In

particular, the warning and safety instructions required by DIN EN 82079-1,

which are necessary for installation, maintenance and troubleshooting on site,

are missing.

These technical information’s are short versions of the operating manuals of the partially filled

LDM and the transmitter. Please contact STEBATEC if you wish to obtain the detailed operat-

ing manuals, which contain the necessary warnings and safety instructions and further infor-

mation.


2 Product features

2.1 The partially filled LDM – brief description

The LDM is a calibrated measuring device for backflow-free flow measurement of wastewater

in open channels or free-flow lines. It has 10 integrated, redundantly arranged and bidirection-

ally operating ultrasonic transit time differential measuring sections and provides accurate flow

measurements in partially or fully filled pipes. The system is suitable for water, wastewater

and raw wastewater and measures reliably even at very low levels. The level measurement is

integrated in the device housing. The system is manufactured without flanges and is clamped

between two pipes with bolts / threaded rods.

The LDM has the following features:

- can be used in partially filled pipes in the water and wastewater industry

- can be supplied for nominal diameters of the LDM measuring pipe from DN 150 to DN 1200.

- has a high resistance to abrasion and chemicals

- measures with a nominal diameter DN 150 from 26.1 mm filling height (for further values

see Table 2 «minimum levels and flow rates Q» on page 17)

- does not have to be calibrated on site, as calibration is carried out completely at the factory

The LDM can be used to measure flow rates of the following liquids:

- Water

- Rainwater

- Wastewater

- Untreated wastewater

- Biologically and chemically polluted wastewater


2.2 Application areas

The need for cost accounting based on the polluter-pays-principle is also increasing in the

wastewater sector. Especially in view of the increasing demands for precise measuring and

control systems, the STEBATEC measuring system offers significant advantages for stationary,

partially filled flow measurement:

- Volume measurement in municipal wastewater associations

- Wastewater outflow control for industrial plants

- Measuring drainage water

- Mining and process water measurements in mining and tunnelling

- Cost accounting measurement

- Extraneous water measurement

- Rainwater measurement


2.3 Structure

The following figure shows an example of a mounted LDM together with the transmitter.

It must be emphasized that the scope of delivery must be looked up in the following chapter 3:

Figure 1 mounted LDM with transmitter

Transmitter

Intermediate unit (transmitter for

level measurement)

Transducer cable

Connection housing of the transmit-

ter

Measuring tube


The following figures show the basic structure of LDM:

Figure 2 LDM principle structure (without full fill sensor)

Transducer cable

Connection hou-

sing of measuring

sensor

Measuring tube

Ultra sonic sensor

Outlet LDM

Grounding connec-

tion

Level meter

Inlet LDM

Connection full-fill

sensor

Outer casing


Figure 3 LDM Principle structure of the full-fill sensor

Full-fill sensor

Transducer cable

Level meter

Grounding connection

Connection full-fill sensor


2.4 Properties

The partially filled LDM consists of an intermediate flange for a transducer with the following

properties:

- Robust design

- IP 66 (IP 67 in preparation)

- ATEX Zone 1

- Power supply 24 V DC

2.5 Device versions

The LDM comes in the following device versions, whereby the individual features can be com-

bined:

- Various nominal sizes (see also paragraph 4.1 «Dimensions and weights»)

- As part of a PNA (pneumatic discharge control from Stebatec) or as a measuring point with-

out connection to a PNA.


3 Scope of delivery

Included in the delivery

- Measuring sensor with integrated level measurement and full-fill sensor

- Transmitter Level measurement

- Sensor cable ultrasonic sensors

o diameter 22.5 mm

o Length is project specific (maximum 25 m)

- Sensor cable level measurement (with the help of a pressure probe)

o diameter 8 mm

o Length of sensor cable from pressure probe to transmitter of pressure probe 7.5 m

o Length of the sensor cable from the pressure sensor to the transmitter of the LDM is pro-

ject-specific

- pre-assembled transmitter

Optional can be supplied:

- Sensor cable full fill sensor, unless the LDM is delivered as part of a PNA

o diameter 4.8 mm

o Length is project-specific

- Threaded screws for mounting the LDM together with the corresponding nuts and washers

- Flange gasket set for sealing between the measuring tube of the LDM and the flanges of the

connecting tubes

- Maintenance opening for cleaning the measuring tube

- Remote transmitter panel for greater distances (>25m) between sensor and transmitter


4 Technical specifications measuring

sensor

The following data are general. For application-specific information, please contact us or your

STEBATEC customer consultant.

Operating conditions

Temperature

Ambient temperature

(Use within ATEX Zone 1) 0…+30°C

Ambient temperature

(Use outside ATEX Zone 1) -20…+50°C

Speed of the liquid

Measuring range -5…+5m/s

Pressure of the liquid

Maximum allowable

pressure (PN) of the LDM 1 bar

Geometry of the bolt circle

for the connecting flange

according to

PN10

Substance data

Deaerated medium There must be no turbulence or air inclusions in the

immediate inlet area.

Electrical conductivity

Non-conductive liquids (<50 pS/m) are prohibited for

reasons of explosion hazard.

Note: Municipal wastewater, seawater and river water

are sufficiently conductive.


Installation conditions

Installation For details refer to chapter 6

«Installation conditions»

Direction of flow

Forward and reverse

See paragraphe 6.2 «Inlet and outlet

side of the measuring tube»

Inflow section ≥ 5∙DN without turbulent flow

≥ 10∙DN with turbulent flow

Outflow section ≥ 3∙DN

Dimensions and weights For details refer to the chapter

«Dimensions and weights».

Materials

Measuring tube LLDPE

Junction box inside LDM and

sheating V4A

Connection housing junction

box

Polypropylene white

Gaskets: EPDM

Ultra sonic sensors PEEK

Permits and certificates

Explosion endangered areas

ATEX Zone 1

IP

IP-Protecion Class IP 66 (IP 67 in preparation)


4.1 Dimensions and weights

Detailed 2D and 3D drawings are available on request. Below are the dimensional drawing and

the table of available sizes and their approximate weights:

Figure 4 Size designation for the table of dimensions below


Dimensions [mm] Approximate

weight

[kg]

Nominal

diameter

DN

a b ØDi ØDa

150 553 300 150 218 23

200 603 350 200 264 28

250 653 450 250 314 33

300 703 500 300 364 40

350 753 550a 350 414 47

400 803 600 400 464 55

500 906 650 500 564 69

600 1010 780 600 664 94

700 1117 910 700 766 130

800 1224 1040 800 868 174

900 1324 1170 900 970 229

1000 1430 1300 1000 1080 362

1100 1536 1380 1100 1185 473

1200 1642 1560 1200 1290 648

Table 1 Dimensions and approximate weights depending on the nominal diameter of the LDM

The geometry of the bolt circle for the connecting flange is based on the standard for PN10.

4.2 Measurement accuracy

Provided that the LDM is maintained at least once every six months or correspondingly more

frequently in case of extreme contamination, the following measurement accuracy of the LDM

can be assumed:

Measurement accuracy of the LDM at full and partial filling:

If the flow velocity of the liquid is higher than or equal to 0.01 m/s, then the uncertainty

of the measured flow is maximum 2 % of the measured value or 0.5 % of the final value

of the measuring range.


4.3 Minimum levels and flow rates

The theoretical minimum measuring ranges for different pipe gradients (grad.) were calcu-

lated. The following table shows the minimum flow rates Q as a function of the pipe gradient

(measured in percent) at which the smallest measurable level (smallest l) is reached. A free,

backflow-free, partially filled discharge was used as the basis for calculation:

DN

[mm]

smallest

l

[mm]

grad.

0.5%

[l/s]

grad.

0.6%

[l/s]

grad.

0.7%

[l/s]

grad.

0.8%

[l/s]

grad.

0.9%

[l/s]

grad.

1%

[l/s]

grad.

2%

[l/s]

150 26.1 0.95 1.01 1.09 1.17 1.24 1.31 1.85

200 26.8 1.16 1.27 1.37 1.47 1.56 1.64 2.32

250 28.0 1.45 1.59 1.71 1.83 1.94 2.05 2.89

300 31.7 2.08 2.28 2.47 2.64 2.80 2.95 4.17

350 33.4 2.54 2.78 3.00 3.21 3.40 3.59 5.07

400 34.8 2.98 3.27 3.53 3.77 4.00 4.22 5.96

500 37.9 4.04 4.42 4.78 5.11 5.42 5.71 8.08

600 40.7 5.19 5.68 6.14 6.56 6.96 7.34 10.38

700 43.4 6.47 7.08 7.65 8.18 8.68 9.14 12.93

800 46.0 7.86 8.61 9.31 9.95 10.55 11.12 15.73

900 48.5 9.38 10.27 11.09 11.86 12.58 13.26 18.75

1000 50.9 10.99 12.04 13.01 13.91 14.75 15.55 21.99

1100 53.3 12.76 13.98 15.10 16.14 17.12 18.05 25.52

1200 55.6 14.63 16.02 17.31 18.50 19.62 20.68 29.25

Table 2 minimum levels and flow rates Q


5 Technical specifications transmitter

The transmitter is mounted separately from the sensor. The housing of the transmitter is

shown below:

Figure 5 transmitter of the partially filled LDM

The following three sections describe technical data of the transmitter.


5.1 Dimensions and weights

In the following Figures, the side view and the sectional view of the transmitter are shown:

Figure 6 side view of the transmitter in section


Figure 7 Sectional view of the transmitter

Below, important masses of the transmitter are listed once again:

Dimensions transmitter

Width (over all) 330 mm

Height (including cable connection) 280 mm

Height (including top mounting bracket

and minimum bending radius of the

transducer cable)

535 mm

Depth 190 mm

Weight approx. 9 kg


5.2 Materials and electrical connections

The materials used and the type of electrical connections of the transmitter are listed below:

Materials

Transmitter Aluminium

Electrical connections

Power supply 24 VDC (-15% / +10%),

PE

Power consumption 25 W

Fuse protection 2.5 A, slow

Communication interfaces

Ethernet (Modbus TCP)

With the Modbus TCP protocol all avail-

able data points can be read and values

of writeable data points can be

changed.

Optional I/O interfaces See description below

Maximum cable lengths (maximum dis-

tance between sensor and transmitter)

25 m (remote panel available, should

the transmitter be installed in an inter-

mediate shaft)

Connection cable (cores) 24 x 2 x 0.22 mm2

Connection cable (diameter) 22.5 mm

The following two optional I/O variants can be installed:


I/O-Option Output

Type of interface of the analog outputs 4 analog outputs

Communicated signals of the analog

outputs

Up to 4 freely selectable data points,

which are recorded in the transmitter,

can be communicated. Examples are:

- Q (measured flow rate)

- vm (measured speed of the liquid)

- v1 - v10: measured speed with paths

1 to 10

- h (measured level of the measuring

tube)

Type of interface of the digital outputs

4 digital outputs, which can be config-

ured either as transistor or as relay

output

Communicated signals of the digital

outputs

Up to 4 freely selectable data points,

which are recorded in the transmitter,

can be communicated.

Examples are:

- Operating message

- Fault

- measured quantity of liquid, commu-

nicated as pulses

I/O-Option Input

Type of interface of the analog inputs 2 analog inputs

Communicated signals of the digital in-

puts

Up to 2 analog inputs can be configured

for the acquisition of external level

measurements.


5.3 Operating conditions

The following conditions must be fulfilled for the transmitter of the partially filled LDM to oper-

ate properly:

Permits and certificates

Explosion endangered areas

ATEX The transmitter is not intended for op-

eration in an ATEX environment.

IP

IP- Protection class IP 54

Operating conditions

Temperature

Ambient temperature (transmitter) 0…+40˚C


6 Installation conditions

It should be noted that the partially filled LDM can only be operated as intended if the condi-

tions listed in the previous chapter 4 «Technical specifications measuring

sensor» and the installation conditions listed below are fulfilled:

6.1 Pipe cross-sections

The inside diameter of the pipe must match the inside diameter of the flowmeter.

6.2 Inlet and outlet side of the measuring tube

The inlet of the measuring tube is determined as follows:

- The inlet of the measuring tube of the LDM is on the side where the sensor cables exit the

connection housing of the LDM. In Figure 2 «LDM principle structure (without full fill sen-

sor)» on page 9 the inlet of the measuring tube is on the left front side: where the inside of

the measuring tube is visible. The outlet of the measuring tube is accordingly on the right

rear side: On the side where the inside of the measuring tube is invisible.

- If the liquid flows into the measuring tube on the inlet side and out of the measuring tube

on the outlet side, it will flow through the LDM in the forward direction after being fixed.

- If the liquid flows out of the measuring tube on the inlet side and into the measuring tube

on the outlet side, it will flow backwards through the LDM.


6.3 Inlet and outlet section

In order to avoid turbulences in the measuring range, the dimensions of the minimum dimen-

sions shown in the following figure for the inlet and outlet sections must be observed during

installation, provided that the flow on the inlet side is calm:

Figure 8 Recommended inlet and outlet sections, top view

Example: If DN = 250 mm, then a and b should be at least

a ≥ 5 ∙ 250 mm = 1250 mm

and

b ≥ 3 ∙ 250 mm = 750 mm

But if the flow is unsteady, then a must be up to 10∙DN.

a ≥ 5∙DN

b ≥ 3∙DN

a b


6.4 Installation before control valve

To avoid turbulences in the area of the measuring paths, no control valve may be installed di-

rectly upstream of the LDM. When measuring in both flow directions, no control valve may be

installed before or after the LDM. If a control valve is installed, it must be installed after the

LDM (see figure below):

Figure 9 Installation control valve after partially filled LDM

If you install a control valve, observe the recommended minimum distances (compare with

section 6.2 «Inlet and outlet side of the measuring tube» above).


6.5 Pipe gradient

The accuracy of the measured flow rates can be influenced by the pipe gradient. For this rea-

son, the gradient must be within 0 % to +2 % (see following figure). If the gradient is known,

the project-specific calibration of the measuring device is carried out at the factory.

≥ 0 %

< 2 %

Figure 10 recommended pipe gradient of the LDM


6.6 Free outlet

If no control damper or gate valve is connected downstream, always use a pipe with free outlet

to prevent backflow into the sensor as shown in the following figure:

Figure 11 free outlet after partially filled LDM

Meaning that:

Num-

ber Designation Meaning

b

This length must be greater than or equal to 3 times the nominal

diameter (≥ 3 DN)

Example: If DN = 250 mm then the following must apply

𝑏 ≥ 3 ∙ 𝐷𝑁 ≥ 3 ∙ 250 𝑚𝑚 = 750 𝑚𝑚

h > 0

Make sure that the water level in the following tank is below the

pipe outlet (the difference h between the lower edge of the outlet

of the measuring pipe and the water surface is greater than zero).

Table 3 free outlet – designation of the points

1

2

1 2 h>0

b


6.7 Spacing of the LDM above ground

The simple removal of the pressure sensor requires that during installation of the LDM space

between the installed pressure sensor and the surrounding ground must be at least 40 mm. If

this space is not taken into account when installing the LDM, the sensor must be removed be-

fore removing the pressure sensor.

Figure 12 minimum space of LDM above ground

6.8 Minimum bending radius cable outlet

The sensor cable of the ultrasonic sensors, which exits from the connection housing of the

measuring sensor, must have a minimum radius of curvature of 225 mm. This radius must not

be undercut, otherwise the cable could break. Compare also with Figure 2 «LDM principle

structure (without full fill sensor)» on page 9.


Figure 13 minimum bending radius of the cable

6.9 Mounting the transmitter

The transmitter is connected to the sensor cable to the sensor of the LDM. Please note that the

transmitter is not designed for use in potentially explosive atmospheres. The maximum cable

length of the sensor cable is 25m.

Alternatively, the transmitter can be installed in an intermediate shaft and a remote transmit-

ter panel can be mounted in the operating room.

6.10 Grounding

The LDM must be connected to the protective earth or electrically connected to the potential

equalization. The liquids to be measured as well as the pipelines must also be grounded.

Whether this is done via potential equalization or via an earth connection is left to the installer.

In any case, a potential independent from the power supply must be connected to the device

from the ground.

Connection hou-

sing measuring

sensor

Measuring

tube


6.11 Vibrations

Neither the connections nor the LDM must be allowed to vibrate during operation:

Figure 14 no vibrations allowed

This condition must be checked especially during commissioning and subsequently during

maintenance.


6.12 Flange offset of the axes of the pipes

The maximum flange misalignment can be understood as a measure for the axial offset after

the installation is completed. The maximum offset of the flange surfaces must not exceed 0.5

mm after installation (see the following figure):

Figure 15 maximum permissible flange offset

Meaning that:

Num-


Lmax maximum distance of the flange from the edge of the LDM

measuring tube

Lmin minimum distance of the flange from the edge of the LDM

measuring tube

Table 4 Maximum permissible flange offset Description of the points

Maximum flange offset of the LDM after installation

It must apply: 𝐿max − 𝐿min ≤ 0.5 𝑚𝑚 respectively 𝐿max − 𝐿min ≤ 0,02‘‘

1

2

1

2

Lmax

Lmin


6.13 Lateral offset of the pipes

The mounted pipes must have the smallest possible lateral offset. Otherwise, turbulence of the

measured liquids is possible, which considerably worsens the quality of the measured flows.

The simplest method to check the offset and its strength is to scan the grooves of the pipe

transitions by hand after installation - if this is possible.

6.14 Mounting position

The transmitter must be installed as shown in the left of the following three figures so that the

activated transit time difference measuring paths are always under water. The deviation of the

installed LDM from the vertical position must not exceed an angle of ±2°. Otherwise the accu-

racy of the measured flows cannot be maintained:

Figure 16 Mounting position of the LDM


6.15 Opening for cleaning

The sensor is highly resistant to dirt. As long as the LDM is serviced at least once every six

months or more often in case of extreme contamination, the measurement will not be dis-

torted by possible contamination. However, it is recommended to make sure that cleaning is

possible by means of an opening directly before or after the transducer (compare with the fol-

lowing figure):

Figure 17 Option for cleaning the LDM

Here ① means the opening for the cleaning.

1


6.16 Mounting under difficult installation conditions

If necessary, contact your STEBATEC customer advisor for alternative solutions if the

installation conditions listed above cannot be met. In this case, for example, the LDM can be

installed between two containers. The inlet of the LDM must be higher than the outlet of the

following container. In this way you ensure a smooth inlet to the flowmeter and thus a highly

accurate measurement. The size of the tanks must be adapted to the size of the LDM

(compare with the following figure):

Figure 18 Mounting under difficult installation conditions

3 h>0

b

5

a

1

2

mE > 1 %

6

mA > 1 %

4


Meaning that:

Num-


mE > 1 %

Prior to LDM, use an inlet vessel (marked ② in the

illustration above) in the inlet pipe has a gradient of

mE > 1 %.

Inlet tank Inlet tank, which must be installed if the gradient of the

inlet pipe is greater than 1 %

h >0

If an inlet tank is used, make sure that the outlet of the

inlet pipe is lower than the inlet of the LDM (the height

difference between the inlet of the LDM and the outlet

of the inlet pipe is therefore greater than 0)

a, b

If an inlet tank is used, the following must apply:

𝑎 ≥ 10 ∙ 𝐷𝑁𝑏 ≥ 5 ∙ 𝐷𝑁

Example: If DN = 250 mm, then the following must

apply:

𝑎 ≥ 10 ∙ 𝐷𝑁 = 10 ∙ 250 𝑚𝑚 = 2500 𝑚𝑚𝑏 ≥ 5 ∙ 𝐷𝑁 = 5 ∙ 250 𝑚𝑚 = 1250 𝑚𝑚

Outlet tank Outlet tank, which must be installed if the slope of the

outlet pipe is greater than 1 %.

mA > 1 %

After the LDM, use an outlet tank (marked ⑤ in the

figure above) if the outlet pipe has a gradient of

mA > 1 %.

Table 5 Mounting under difficult installation conditions - description of the points

1

2

3

4

5

6


7 Installation

7.1 Fixing

For fixing, it is important to observe the tightening torques listed below.

Procedure for tightening the bolts/threaded rods

- Always tighten the bolts evenly and crosswise.

- Take care not to exceed the maximum torque value.

- Step 1: approx. 50% of the max. torque indicated in the table.

- Step 2: approx. 80% of the max. torque indicated in the table.

- Step 3: 100% of the max. torque indicated in the table

Figure 19 Fixing the bolts


Nominal

diameter

DN [mm]

Connection

pressure

stage

Bolts

50% Max.

tightening

torque [Nm]

80% Max.

tightening

torque [Nm]

Max.

tightening

torque [Nm]

150 PN 10 8 x M20 8 13 16

200 PN 10 8 x M20 10 15 19

250 PN 10 12 x M20 8 12 15

300 PN 10 12 x M20 9 14 18

350 PN 10 16 x M20 8 13 16

400 PN 10 16 x M24 10 15 19

500 PN 10 20 x M24 9 14 18

600 PN 10 20 x M27 13 20 25

700 PN 10 24 x M27 13 20 25

800 PN 10 24 x M30 19 30 38

900 PN 10 28 x M30 18 29 36

1000 PN 10 28 x M33 25 40 50

1200 PN 10 32 x M36 33 52 65

Table 6 Fixing bolts for installation LDM

7.2 Parameterization

The transmitter of the LDM must be parameterized.


8 Maintenance

STEBATEC's products are designed in such a way that they do not require any additional tools

for installation and removal during maintenance work. In the following sections the cleaning of

the LDM is described.

8.1 Cleaning the LDM

The inside of the measuring tube must be accessible for cleaning (compare with the optional

opening flap in Figure 17 «Option for cleaning the LDM» on page 34. If access to the inside of

the LDM measuring tube is possible, the LDM must be cleaned as follows to clean the inside of

the measuring tube:

- The measuring tube is cleaned by means of a high-pressure cleaner by inserting its lance

into the measuring tube and hosing down the inner walls of the measuring tube of the LDM

at a flat angle.

- The membrane of the pressure probe (which is used as a level meter) should not be cleaned

for long durations with a high-pressure water jet.

- Check whether the LDM again shows plausible flow values.

8.2 Removal and installation

A lifting device (e.g. winch, pulley block or crane) is recommended for safe installation in

shafts and ducts. This allows the operating personnel to manoeuvre the device safely in the

sewer or shaft.

Avoid placing or hitting the device too hard, as this can cause damage to the system.

Cables and hoses must be secured against pulling or kinking. Any damage must be docu-

mented photographically and the resulting photos must be sent immediately to STEBATEC to-

gether with a description.

Sharp edges or other pointed objects protruding into the duct must be removed in advance.

When using a suspension adapter, the unit is aligned exactly during the first installation. Any

further maintenance-related installation and removal can be carried out without tools. Re-

alignment is not normally necessary, but the alignment must be checked.


8.3 Recommissioning and function check

Functional checks or recommissioning are necessary after a major event. This can happen after

- a major flooding

- a long power outage

- conversions

- renovations

8.4 Maintenance of value

If the maintenance and repair work is not carried out according to the specifications during the

warranty period, or if it can be determined that parts of the system have been seriously ne-

glected, services will be charged for the restoration.

The following activities must be carried out by the maintenance personnel:

Measures to preserve value

How often? Which measures?

When reporting

pollution

The transmitter of the LDM sends a binary signal,

which indicates whether the LDM is contaminated. If

this binary signal is present, the LDM must be

cleaned thoroughly. (compare with section 8.1

«Cleaning the LDM» above).

All ½ Years

The LDM must be examined for damage.

It must be checked whether the LDM begins to os-

cillate during operation. This would result in a falsi-

fication of the measurement results and must be

prevented.

Every year The screw connections of the LDM must be checked

and tightened if necessary.


9 Contact

There are several ways to contact us.

If you would like to report a malfunction/problem of the system, we ask you to provide us with

photos and a description of the problem.

Tell us the location, system name and serial number of the system.

Switzerland (Headquarter)

STEBATEC AG

Mattenstrasse 6a

CH-2555 Brügg

Phone: +41 32 373 15 71

Fax: +41 32 373 15 63

[email protected]

www.stebatec.ch

Germany

STEBATEC GmbH

Heilbronner Straße 150

D-70191 Stuttgart

Phone : +49 322 2109 3142

[email protected]

www.stebatec-messtechnik.de

It is important to us to manufacture a great product together with optimal documentation. But

for this we need your help. If you see any room for improvement regarding this product or the

"Technical Information", please do not hesitate to contact us at [email protected].

Many thanks in advance for this!

ldm partially filled - stebatec€¦ · the ldm is a calibrated measuring device for backflow-free...

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