SERVING THE GAS INDUSTRY WORLDWIDE
Technical Product Information
ROTARY DISPLACEMENT METER DKZ 04
RMG MESSTECHNIK GMBH
ROTARY DISPLACEMENT METER DKZ 04 Fields of Application, Operating Principle and Construction
Operating principle
2
The rotary displacement meter is a volumetric meter for measuring gas in closed pipelines. If there is a pressure loss in the section from the inlet to the outlet of the meter, this causes a rotational torque at the rotary pistons. When this torque exceeds the steady-state torque of the parts to be actuated, the rotary pistons start to rotate in the direction of the arrows. In the course of the rotational movement, the chambers forming between the rotary pistons and the case are filled and evacuated so that the rotation of the pistons represents a measure for the volume that has flowed through. A matching gearing is used to translate this rotational movement to a totalizer which continuously counts the gas volume in working cubic metres. In the measuring chamber, there is no metallic contact and the rotary pistons run very smoothly. Measurements start below Δp < 0.1 mbar and at Q ≈1/1000 Qmax.
Application RMG's rotary displacement meters have been designed for measuring gaseous fluids. They are mainly used • in public gas supply - in gas transfer and measuring stations - for measuring gas consumption and distribution in communities and at gas suppliers as well as gas consumption of final consumers, such as steel works, brick works and the glass industry, and in heating systems of schools and hospitals, block heating systems, etc. • in the chemical industry for measuring gas consumption and distribution, in some cases with process gas control. • in the automotive industry for determining the intake air volumes of combustion engines in engine and development test stands. • in the industry for measuring the consumption of compressed air.
• in compressor technology in order to determine the volume of air generated in test stands.
Design and structure DKZ 04 rotary displacement meters are built for the PN 10 and PN 16 pressure classes. The pressurized parts are made of spheroidal graphite iron, while the rotary pistons are made of anodized light metal. The anodized coating makes the piston surface considerably more resistant to wear and tear. Overdimensioned bearings and hardened and ground gears used for synchronizing the rotary pistons ensure smooth running. From a rotary piston shaft, the rotational movement is transferred in a pressure-tight and contact-free way through a magnetic coupling from the pressure compartment to the totalizer drive shaft. The latter carries the magnetic core and drives the totalizer gears with its finely stepped adjusting gear ratio inside the unpressurized totalizer case as well as the double 8-digit roller-type index. Up to the size of G 400, the meters are built in flanged design; larger meters have screwed-on feet. All RMG gas meters fulfill the constructional requirements of DVGW Code of Practice G 492/II, DIN 30690 T 1, DIN 3230 T 5 and the Pressure Equipment Directive (PED) 97/23/EC and are subjected to the mechanical strength and leak tests specified therein. The case materials satisfy the requirements of EN 13445-2 with PED QM certification and EN 10204/3.1 inspection certificate. DKZ 04 rotary displacement meters from RMG of course also meet the requirements of the European standard for rotary displacement meters EN 12480.
Gas types The meters can be used for measuring all non-corrosive gases in accordance with DVGW Code of Practice G 260 as well as natural gas, town gas, coke-oven gas, refinery gas, propane, butane, LPG-air mixture, methane, ethylene, hydrogen and other gases.
ROTARY DISPLACEMENT METER DKZ 04 Features and Operating Conditions
Features · Pressure classes: PN 10 and PN 16 · Nominal diameters: DN 50 to DN 200 · High-temperature resistant design as standard up to an operating pressure of 5 bar for the meter 7.241 sizes G 40 to G 400. 01.04 · Wide measuring range up to 1:160 for custody transfer metering.
· PTB-approved · Excellent reproducibility. · Verification period: 16 years · Low on maintenance Oil change every 16 years with clean and dry gases.
Errors of measurement and operating resistance Requirements for higher measuring accuracy and reliability over a wide measuring range or in the case of intermittent operation open up a multitude of possible uses for the volumetrically metering rotary displacement meter, in particular at industrial gas consumers or in conjunction with heating systems. The reproducibility of measured values is excellent and remains stable over many years with normal operation. Subsequent verifications of Pintsch rotary displacement meters which have been in use for as long as 50 years in most cases have virtually shown no deviations of their error curve from that of their state when new. Thanks to a special production method, tightest manufacturing tolerances are achieved with high precision with this measuring system operating on the Roots principle. Thus, measuring ranges of up to 1:160 are possible. Bearings and gears have been optimized to ensure smooth running and a low pressure loss Δp. It varies in rough approximation proportionally with the density of the gas and squarely with the meter load. The Δp values for the individual meter sizes at Qmax are shown in the table on page 6.
· Pressure and temperature taps are located on both sides of the meter case.
· Double digital index fitted as standard enables the direction of flow to be changed on site without official supervision.
· No inlet or outlet pipes are required. · Suitable for intermittent operation e.g. in heating systems.
· No slow-down effect of the meter after the flow has stopped.
· Independent of pressure, i.e. no high-pressure offset.
· Long-term stability of measurements.
Temperature at measurement conditions The normal gas temperature range should be from -10°C to +40°C. Please contact us if you intend to use the meters with gases at higher or lower temperatures. The meters can be stored at temperatures from -20°C to +60°C.
High-temperature resistance Due to the fact that the gas meters do not involve an additional risk in the case of a fire, RMG's DKZ 04 rotary displacement meters from sizes G 40 to G 400 are built in such a way that they fulfill the requirements for high-temperature resistance in accordance with EN 12480 and DIN 3374.
Positions of installation RMG's rotary displacement meters have been designed for both horizontal and vertical directions of flow and the position of the totalizer can be changed without official supervision.
3
ROTARY DISPLACEMENT METER DKZ 04 Totalizer and Measuring Accuracy
Sizes G 40 to G 400
Measuring uncertainty
The level-check plugs are located in such a way that the gas meters can be installed horizontally and vertically. Thus, they can be turned through 90° and only the totalizer case has to be adjusted to the new position of use (without official supervision).
RMG's DKZ 04 rotary displacement meters are measuring instruments suitable for custody transfer metering. If desired by the customer, they are officially verified by us in accordance with applicable German or EC regulations or tested with the officially approved measuring equipment in our factory and delivered as specified. The measuring system offers the following advantages: • wide measuring ranges with narrow error limits, • excellent reproducibility (approx. 0.1%), • virtually no hysteresis, • high measuring accuracy even in the case of intermittent flow rates such as those prevailing in heating systems for example, • no slow-down effect of the gas meter after the flow has stopped, • high stability of measurements, i.e. virtually no changes of measurement errors over many years, • excellent high-pressure performance, i.e. the measuring result is independent of the pressure.
Sizes G 650 to G 1000 The location of the oil level indicators and the fastening feet can be adjusted to a horizontal or vertical position of installation. So the gas meters can be turned through 90°, while the oil level indicators and the fastening feet can be screwed on and the totalizer case adjusted to the new position (without official supervision).
Added flexibility thanks to a double digital index RMG's DKZ 04 rotary displacement meters are fitted with a double digital index which enables the gas meter to be adapted to the direction of flow without changing the totalizer and without official supervision on the initial start-up of the meter. This mainly reduces the stocking of parts and avoids costs for short-term changes of planned plants. On-site adjustment to the desired direction of flow can be made easily and without any tools. The double digital index has two counter-running indicators which are covered by a plate on delivery. After the direction of flow has been determined, the appropriate indicator is uncovered. If necessary, the meter head can be turned through 90° by loosening two hexagon socket head screws. Further features: • 1 LF pulse transmitter fitted as standard. • Additional (HF or LF) pulse transmitters can be installed. • A mechanical drive shaft in accordance with DIN 33800 can be retrofitted.
The verification regulations specify the measurement error limits (of the instantaneous value) shown. The error values are located on a typical error curve as shown in the figure below. +2 Measurement error in %
4
+1 0 -1 -2 Qmin
Qmax Measuring range
In the case of a verification in accordance with EC regulations (with a measuring range of 1:10 or 1:20), measurement error limits are ±2% up to 20% of the maximum flow rate Qmax and ±1% beyond this flow rate. In the case of a verification in accordance with German regulations, the measuring ranges of 1:30, 1:50, 1:100 and 1:160 are also possible. Here, however, the measurement error limit of 1% starts already at 15%, 10%, 8% or 6% of Qmax.
ROTARY DISPLACEMENT METER DKZ 04 Dimensions and Weights
Dimensions and weights Nomi- Meter Press. nal dia. size class PN DN
*
**
Drilling pattern of connecting flanges to EN 1092-2
a
c
e
f
h³
mm
mm
mm
mm
mm
øk
***
Number
D
d2
d2
s
Applicable to all tables:
Approx. weight
kg
50
G40
16
150
261 131.5 392
80
125
-
M 16
4
20
30
50
G65
16
150
291 161.5 452
80
125
-
M 16
4
20
31
*
Face-to-face length according to EN 12480 ** Recommended distance to the wall for maintenance work *** Through-hole thread / blindhole thread (depth = s)
a
f e
c
a
Nomi- Meter Press. nal dia. size class PN DN
80
G100
16
*
**
Drilling pattern of connecting flanges to EN 1092-2
a
c
e
f
h³
mm
mm
mm
mm
mm
øk
230
294
164
458
80
160
D
***
Number
d2
d2
210 M 16
s
Approx. weight D
kg
8
20
38
Øk DN
80
G160
16
230
349
164
513
80
160
210 M 16
8
20
48
100
G160
16
230
349
164
513
80
180
229 M 16
8
20
46
100
G250
16
340
333
189
522
85
180
229 M 16
8
20
75
150
G400
16
340
383
239
622
85
240
285 M 20
8
24
90
S
f e
c
d2
a
a
Nomi- Meter Press. nal dia. size class PN DN
*
**
a
c
e
mm mm mm 150
200
G650
G1000
f mm
g
h³
Dimensions of the meter foot
m
i
k
i1
Drilling pattern of conncting flanges to EN 1092-2
k1
mm mm mm mm mm mm
mm
øk
***
Number
D
d2
d2
Approx. weight
kg
10
400 452 268 862 440 100 270 570 510 440 380 240
285
23
8
26
210
16
630 502 315 902 460 150 440 640 550 640 550 240
318
23
8
37
420
10
400 522 268 1002 440 100 410 570 510 440 380 295
340
23
8
26
260
16
630 572 315 1042 460 150 580 640 550 640 550 295
381
23
12
41
580
c
g
40
ø 110
s
S
h*) a
a 112 m f
k i
k1 i1
5
ROTARY DISPLACEMENT METER DKZ 04 Measuring Ranges, Installation and Maintenance
Measuring ranges / pressure loss Measuring ranges, custody transfer metering Nominal dia.
6
´ Meter size*)
EC approval EEC 1.33-3271.3-AEM-E01
Pressure loss Δp at Qmax and
German approval 1.33-3271.3-AEM-N01
1 : 10 Qmin
1 : 20 Qmin
1 : 30 Qmin
1 : 50 Qmin
1 : 100 Qmin
1 : 160 Qmin
ρ = 1 kg/m3
Qmax
Smallest counter Up
DN
-
[m3/h]
[m3/h]
[m3/h]
[m3/h]
[m3/h]
[m3/h]
[m3/h]
[mbar]
[m3/U]
50
G 40
65
6
3
2
1.3
0.65
-
2
0.1
50
G 65
100
10
5
3
2
1
0.6
3
0.1
80
G 100
160
16
8
5
3
1.6
1
3
1.0
80
G 160
250
25
13
8
5
2.5
1.6
4
1.0
100
G 160
250
25
13
8
5
2.5
1.6
4
1.0
100
G 250
400
40
20
13
8
4
2.5
5
1.0
150
G 400
650
65
32
20
13
6.5
4
5
1.0
150
G 650
1000
100
50
32
20
10
-
5
1.0
200
G 1000
1600
160
80
50
32
16
-
6
10.0
*) Meter sizes beyond G 1000 on request
Installation and maintenance
Mechanical drive shaft
RMG's DKZ 04 rotary displacement meters do not require any inlet pipes. The gas and the pipeline have to be clean; it is recommended that a start-up strainer be installed temporarily. The gas meters are splash-lubricated. The oil level can be checked by means of level-check plugs. Depending on the operating conditions, oil has to be changed at intervals between 5 and 16 years. The totalizer does not require special maintenance within the period of validity of the verification of 16 years. For further information, see the operating instructions.
All meter sizes can optionally be operated with a mechanical drive shaft without any restriction of the measuring ranges. For connecting additional equipment, a mechanical drive shaft is available ex works or can be retrofitted on site under official supervision. The connecting dimensions for the equipment to be connected conform to DIN 33800. The rotation rates and the permissible connecting torques are shown in the table on page 7. The mechanical drive shaft can be used, for example, to attach the following additional equipment, while taking account of Mmax: • pulse transmitters (as per the table) • mechanically actuated gas volume correctors • electronic compact correctors (devices from other manufacturers) • encoder index.
ROTARY DISPLACEMENT METER DKZ 04 Pulse Transmitters and Accessory
Pulse transmitters built into the totalizer case RMG's DKZ 04 rotary displacement meter is fitted as standard with a Reed contact as LF pulse transmitter (optionally, a double pulse transmitter) with frequencies of up to a maximum of 0.3 Hz. In addition, LF (Reed or inductive) pulse transmitters of up to 3 Hz or HF (inductive) pulse transmitters with frequencies of up to 460 Hz can be fitted (see table).
Pulse transmitters at the mechanical drive shaft
public gas supply can be performed. Furthermore, the HF pulse transmitters enable high-resolution instantaneous values (e.g. m3/h) to be generated, which are frequently used on engine test stands. It is possible in particular to install a compact volume corrector, e.g. of type EC 900, directly on the meter which is connected to the LF output of the meter. If an EC 900 is used, the corrector can be installed together with a three-way check valve in the factory and the meter parameters can be programmed accordingly, so that a ready-to-install entity is delivered.
Optional accessory
In addition to the built-in pulse transmitters, another pulse transmitter can be attached via the standardized mechanical drive shaft in accordance with the table.
Connection of additional equipment
• For temperature measurement, screw-in threaded sleeves are available in various thread sizes (G¼ / G½). • To protect the gas meters against soiling, start-up strainers are optionally available in various designs (conical strainers or mesh seal). • Encoder index on request.
Thanks to the pulse transmitters which can be fitted in the totalizer or additionally attached via the mechanical drive shaft (see page 7), the common measuring tasks of
Pulse transmitters and connection options Built-in pulse transmitters
Drive shaft (optional)
Built-on pulse transmitters (optional) to be attached to the drive shaft
optional
optional
standard optional
[m3/P]
f at Qmax
[m3/P]
0.01
360 Hz
0.1
Rotation rate
Permissible torque
Ua
Mmax
[m3/P]
[m3/U]
[Nmm]
0.01
0.01
0.01
400 Hz
0.1
0.01
0.01
G 100
0.1
400 Hz
1.0
0.1
0.1
G 160
0.1
460 Hz
1.0
0.1
0.1
G 250
0.1
400 Hz
1.0
0.1
0.1
G 400
0.1
440 Hz
1.0
0.1
0.1
G 650
0.1
250 Hz
1.0
0.1
0.1
G 1000
1.0
280 Hz
10.0
1.0
1.0
Reed switch
Diode No approval for explosion protection
[m3/P]
[m3/P]
[m3/P]
[m3/P]
[m3/P]
0.001 2
G 65
Inductive switch
0.0005 x Ua up to 1 x Ua
Reed switch
0.1 x Ua up to 100 x Ua
G 40
Inductive switch
0.010 5
or 0.10
20
0.010
or
0.010
0.10 or 1.0
0.01 x Ua up to 100 x Ua
Meter size
0.10
1.0
7
SERVING THE GAS INDUSTRY WORLDWIDE
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Furthermore, we design and build plants according to your requirements and offer you reliable and state-of-the-art solutions in station automation as well. Please contact us. We look forward to your challenges.
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Edition 10/2007
Rotary displacement meter DKZ 04