SMART DIFFERENTIAL PRESSURE TRANSMITTER

WITH TWO DIAPHRAGM SEALS

MODEL APR-2000ALW (former APR-2200ALW)
ü 4...20 mA output signal + HART 5 / HART 7 protocol
ü Accuracy 0,1% /SIL3
SIL2 version
y
ü Safety version SIL2/SIL3 safet
ü Intrinsic safety certificate ATEX, IECEx, FM (USA, Canada), INMETRO,
UKCA, KCS
ü Explosion proof certificate ATEX, IECEx, FM (USA, Canada), INMETRO,
UKCA, KCS
ü Marine certificate – DNV, BV
ü Fully welded sensor guarantees tightness of oil system for many years
ü Ability to configure measuring range locally

Transmitter
with two remote
diaphragm seals Differential
pressure transmitter

Coiled
excess capillary

Capillary outlet
in the axis of the
diaphragm seal
Diaphragm seals

Example of a filter loss measurement

Recommendations
The version of the transmitter with two remote capillaries are identical, as short as possible, and
diaphragm seals is recommended for the measurement terminated with identical seals. At such a configuration
of pressure differences when the hydrostatic pressure of additional temperature errors, related to the remote
the manometric fluid in the capillaries (which depends on sealing, affect both of the measurement chambers of the
the vertical spacing of the seals) is significantly less than differential pressure transmitter in the same way, and
the measuring range of the transmitter. The best thus cancel each other out.
metrological results are obtained when the applied

II/ 26
 Transmitter with two types of diaphragm
seal: one – direct diaphragm seal and the
other – remote diaphragm seal

Upper remote diaphragm seal

Capillary fastened to a guide

Coiled
excess of the capillary

Differential
pressure transmitter

Lower direct seal

Example of measurement of the level in a pressure tank

Recommendations
The transmitter with a direct diaphragm seal (connected This phenomenon is counteracted by the elastic reaction
to the positive measurement chamber) and a remote of the diaphragm of the upper diaphragm seal, which is
diaphragm seal (connected to the negative chamber) is displaced by the change in volume of manometric fluid.
recommended for hydrostatic measurements of: levels, Based on tests and experiments, the Aplisens
densities, phase boundaries and pressure differences transmitters are provided with carefully selected seal
(with differentiated height of pulse source points*). diaphragms, which guarantee compensation of the
errors resulted from the ambient temperature changes.
In such a configuration, at ambient temperature
changes, two opposite phenomena appear concurrently. The best metrological results are obtained using
assembly, which include DN 80, DN 100, A 109 and
Thermal expansion causes the change in the volume S-Comp diaphragm seals or S-Mazut, S-DIN and
(and hence also the change in density) of the S-Clamp diaphragm seals with a diameter of at least 65
manometric fluid in the capillary, which results in a mm, where the length of the capillary is (1...1.3) ×
change of the hydrostatic pressure related to the vertical (vertical spacing of seals). It is recommended using
spacing of the seals. identical diaphragm seals at the both upper and lower
connection points.
* The difference in height of pulse source points, at which the hydrostatic pressure of the manometric fluid is comparable to or greater than the range of the transmitter.

II/ 27
 Example versions
Aluminium casing with
M20×1.5 packing gland
Degree of protection IP 66
Type APR-2000ALW

S-CompK
diaphragm seal
M20×1.5 or Æ51

Transmitter with two

S-DIN K
types of diaphragm seal:
diaphragm seal one – direct diaphragm
Æ50, Æ65, Æ80 seal and the other –
remote diaphragm seal.
The example with S-T
DN80 diaphragm seal.

S-ChK
diaphragm seal

S-TK
diaphragm seal
34.5

34.5 transmitter with two

remote diaphragm seals.
S-PK Example with S-PK
diaphragm seal

Note: The appropriate configuration of the complete set of pressure transmitter, diaphragm seals and capillaries, as well as the proper selection
of manometric fluid, depends on several factors, including the physical and chemical properties, temperature range of the medium, the vertical
spacing of the diaphragm seals, the measuring range, static pressure range, range of ambient temperatures and the technical specifications for
mechanical connection of the diaphragm seals to the pressure devices.

II/ 28
 Application and construction Configuration
The differential pressure transmitter is applicable The settings of the following metrological parameters
to the measurement of pressure differences of: gases, can be changed:
vapours and liquids in cases where it is necessary ¨ the units of pressure in which the range is configured,
to use seals and the pressure pulse source points may ¨ start and end points of the range, time constant,
be several metres apart. Typical applications include ¨ inverted characteristic (output signal 20 ÷ 4 mA).
the hydrostatic measurement of: levels in closed tanks, Communication
densities and phase boundaries, and the measurement The transmitter is configured and calibrated using a KAP-03
of a filter loss, pressure differences between media communicator, some other communicators (HART) or a PC using
in pasteurisers etc. The available range of the dia- an HART/USB converter and Aplisens RAPORT 2 configuration
phragm seals allows measurement at great majority of software.
media. The active element is a piezoresistant silicon The data interchange with the transmitter enables the users
sensor separated from the medium by a distance seal- the transmitter identification, as well as reading of the currently
ing system. The special design of the measuring unit measured differential pressure value, output current and percent
means that it can withstand pressure surges and over- of range width.
loads of up to 40 bar. The electronic circuits are en-
closed in a casing with a degree of protection IP 65
or IP66.
Measuring ranges
Nominal Minimum set range Vertical spacing Maximum set range width, Static
measuring range of diaphragm considering the actual vertical spacing pressure limit
(FSO) seals of the diaphragm seals (m)
-160…160 mbar 0,1 m H2O £ 1,7 m [1,6 + (vertical spacing of seals × 0,94)] m H2O 40 bar
-0,5…0.5 bar 0,5 m H2O £ 6 m [5 + (vertical spacing of seals × 1,04)] m H2O 40 bar
-1,6…2 bar 1,5 m H2O £ 15 m [20 + (vertical spacing of seals × 1,04)] m H2O 40 bar
-1,6…16 bar 1 bar £ 15 m 16 bar 40 bar
CAUTION: The maximum vertical diaphragm seal spacing shown in the table applies to level measurement, ensuring that it is possible to
set the zero point of the transmitter when the tank is empty. For measurements of density or phase boundaries (in the sugar, chemical
or refinery industries) the vertical spacing of the diaphragm seals can be larger.

Metrological parameters Electrical parameters

Accuracy £ ±0.1% (FSO) As given in the sheet for the APR-2000ALW differential pressure
The other parameters as given in the sheet for the transmitter.
smart differential pressure transmitter Operating conditions
APR-2000ALW.
Sealing effect errors – as given in the relevant dia-
Operating temperature range (ambient temperature) -25...85°C
phragm seal sheet in chapter III (Diaphragm Seals),
Exia, IS version: -25...80°C
concerning the distance seal.
Exd, XP version: -25...75°C
NOTE: The additional absolute zero error due to ambi-
ent temperature can be compensated by configuring Medium temperature range – as given in the appropriate
the transmitter, seals and capillaries in accordance with diaphragm seal sheet (remote seal)
the recommendations on pages II/ 20 and II/ 21.

Ordering procedure
Model Code Description
APR-2000 Smart differential pressure transmitter
/ALW……………........………………………………..… With display, output 4-20mA + Hart
/ALW/Safety................................................................ With display, output 4-20mA + Hart
Versions Functional Safety certificate according to PN-EN 61508:2010 parts 1 ÷ 7,
PN-EN 61511-1:2017 + PN-EN 61511-1:2017/A1:2018-03,
PN-EN 62061:2008 + PN-EN 62061:2008/A1:2013-06 + PN-EN 62061:2008/A2:2016-01
/SS………………………………………………... Stainless steel housing
/Exia…………………………………………….... II 1/2G Ex ia IIC T4/T5 Ga/Gb
IECEx Ex ia IIC T4/T5 Ga/Gb
/Exia (Da)……………………………………….... II 1/2G Ex ia IIC T4/T5 Ga/Gb
II 1D Ex ia IIIC T115°C Da
I M1 Ex ia I Ma (version with SS housing)
Ex ia IIC T4/T5 Ga/Gb
IECEx Ex ia IIIC T115°C Da
Certificates, options * Ex ia I Ma (version with SS housing)
/IS…………………………………………………. IS Class I, Div 1, Groups A, B, C, D T4
IS Class II, Div 1, Groups E, F, G T5
IS Class III, Div 1, T5
Zone 0 AEx/Ex ia IIC T4 Ga
Zone 20 AEx/Ex ia IIIC T105°C Da
/ISB……………………………………………….. Ex ia IIC T5/T4 Ga/Gb
Ex ia IIIC T105°C Da
Ex ia I Ma (version with SS housing)
See next page

II/ 29
 Code Description
/ISK……………………………………………….. Ex ia IIC T5/T4 Ga/Gb
Ex ia IIIC T105°C Da
/ISUK…………………………………………….. II 1/2 G Ex ia IIC T5/T4 Ga/Gb
II 1 D Ex ia IIIC T105°C Da
I M1 Ex ia I Ma (version with SS housing)
/Exd……………………………………………….. II 1/2G Ex ia/db IIC T6/T5 Ga/Gb
II 1/2D Ex ia/tb IIIC T85°C/T100°C Da/Db
I M2 Exd ia I Mb (version with SS housing) Packing gland available on
Ex ia/db IIC T6/T5 Ga/Gb request
IECEx Ex ia/tb IIIC T105°C Da/Db
Ex db ia I Mb (version with SS housing)
/Exd (2G)…………………………………………. II 2G Ex db ia IIC T6/T5 Gb
II 2D Ex ia tb IIIC T105°C Db Packing gland available on
Ex db ia IIC T6/T5 Gb request
IECEx
Ex ia tb IIIC T105°C Db
/XP………………………………………………... XP Class I, Div 1, Groups A, B, C, D T5
DIP Class II, Div 1, Groups E, F, G T5
Packing gland available on
DIP Class III, Div 1, T5
request
Zone 1 AEx db ia IIC T5 Gb
Zone 21 AEx ia tb IIIC T105°C Db
/XPC……………………………………………… XP Class I, Div 1, Groups B, C, D T5
DIP Class II, Div 1, Groups E, F, G T5
Packing gland available on
DIP Class III, Div 1, T5 request
Zone 1 AEx/Ex db ia IIC T5 Gb
Zone 21 AEx/Ex ia tb IIIC T105°C Db
/XPB……………………………………………… Ex ia/db IIC T6/T5 Ga/Gb
Packing gland available on
Ex ia/tb IIIC T105°C Da/Db
request
Ex db ia I Mb (version with SS housing)
/XPK……………………………………………… Ex ia/db IIC T6/T5 Ga/Gb Packing gland available on
Ex ia/tb IIIC T105°C Da/Db request
/XPUK……………………………………………. II 1/2 G Ex ia/db IIC T6/T5 Ga/Gb
Packing gland available on
II 1/2 D Ex ia/tb IIIC T105°C Da/Db request
I M2 Ex db ia I Mb (version with SS housing)
/Exia(Da)/Exd……………………………………. Dual certification Exia(Da) and Exd
/Exia(Da)/Exd(2G)………………………………. Dual certification Exia(Da) and Exd(2G)
/IS/XP…………………………………………...... Dual certification IS and XP for US
/IS/XPC…………………………………………... Dual certification IS and XPC for US and Canada
/ISB/XPB…………………………………………. Dual certification IS and XP and for Brazil
/ISK/XPK…………………………………………. Dual certification IS and XP and for Korea
/ISUK/XPUK…………………………………… Dual certification IS and XP and for United Kingdom
/SA………………………………………………... Surge arrester for Exia version
/MR……………………………………………….. Marine certificate – DNV, BV
/250 bar............…............................................. Static pressure 250 bar (for transmitter with two remote diaphragm seal)
*- more than one option /700 bar............…............................................. Static pressure 700 bar (for transmitter with two remote diaphragm seal)
is available /IP67…………………………………………….... Protection class IP67
/Hart 7..…………………………………………… Communication protocol HART in revision 7
Range Min. set range
/-160÷160 mbar.............................……. -160÷160 mbar (-16÷16 kPa) 0,1 mH2O
Nominal measuring range /-0,5÷0,5 bar.............................……….. -0,5÷0,5 bar (-50÷50 kPa) 0,5 mH2O
/-1,6÷2 bar.............................………….. -1,6÷2 bar (-160÷200 kPa) 1,5 mH2O
/-1,6÷16 bar.............................………… -1,6÷16 bar (-160÷1600 kPa) 1 bar
Measuring set range /…÷… [required units] Calibrated range in relation to 4mA and 20mA output
/(+)………………………….. Direct diaphragm seal or remote diaphragm seal mounted on the (+) side of the
transmitter- code as given in the relevant diaphragm seal sheet
K=……………………………... Capillary length on (+) side of transmitter
Process connections
/(-)…………………………... Remote diaphragm seal mounted on the (-) side of the transmitter – code as given in
the relevant diaphragm seal sheet
K=……………………………... Capillary length on (-) side of transmitter
(without marking) Packing gland M20x1,5
Electrical connection
/US................................. Thread 1/2”NPT Female
Accessories /FI25………...… Mounting bracket for 1” pipe, mat. Stainless Steel
Other specification /............... Description of required parameters

Standard display configuration

Std. version Exia, Exia(Da), IS Exd, XP Exia(Da)/Exd, IS/XP Safety
Backlight on · · ·
Backlight off · ·
Other configuration of display has to be marked upon placing order. User has no possibility of switching backlight on/off.

II/ 30
 To simplify the mathematical operations we introduce the density coefficient of the medium Xr.
rmedium [g/cm3 ]
Xr =
rwater at 4 °C [g/cm3 ]
Since the density of water at 4°C is 1 g/cm3, the density coefficient Xr is numerically equal to the density of the me-
dium expressed in g/cm3. To determine the hydrostatic pressure of a column of liquid in mm H2O, it is sufficient to multiply
the height of the column h [mm] by the density coefficient of the liquid Xr. Since it is easy to determine the hydrostatic
pressure in mm H2O and the transmitter can be configured in those units, in the descriptions of measurement methods
given below we will make use of pressures expressed in mm H2O and the density coefficient Xr.

Configuration of the transmitter to measure the level of liquid in a tank

The measurement task: 4. On the configuration menu select the “Reranging” pro-
To convert a variation in the level of a liquid with density cedure.
r = 0.87 g/cm3 between 0 and hmax to a variation in the 5. On the “Reranging” menu:
output signal from 4 to 20 mA. a) change the units of measurement to mm H2O at 4°C;
b) enter the values for the start (Xń × hmin [mm]) and
end (Xr × hmax [mm]) of the measurement range,
namely 0 and (0.87 hmax [mm]) respectively;
c) to compensate for the hydrostatic pressure of the
manometric fluid, the start of the measurement range
should be set using regulated pressure; when sub-
ject to the action of only the manometric fluid (empty
H – vertical tank) the transmitter will shift the start and end-points
spacing of of the range, compensating for the value of that
H

diaphragm pressure.
seals
0 £ h £ hmax ρ
When the transmitter has been configured in this way it is
ρ = 0.87 g/cm3 ready to be used to carry out the given measurement task.
h

If it is not possible to empty the tank to configure the

transmitter, the hydrostatic pressure of the manometric
fluid should be calculated by multiplying the vertical spac-
4...20 mA I ing of the diaphragm seals by the density coefficient of the
DP oil in the capillaries. This pressure should be taken into
account when entering the values for the start and end of
1. Install the transmitter in its working position on an the range:
empty tank. Start [mm H2O] = –H [mm] × Xroil
2. Make the electrical connections of the transmitter, End [mm H2O] =
providing for the ability to use HART communication. = hmax [mm] × Xrmeasured liquid – H [mm] × Xroil
3. Connect the KAP-03 communicator, identify the
transmitter and select the “configuration” function. roil for DC-550 oil is equal to 1.068 g/cm3
roil for AK-20 oil is equal to 0.945 g/cm3

Configuration of the transmitter to measure density of liquids

The measurement task:
To convert a variation in liquid density from
rmin = 0.6 g/cm3 to rmax = 1.2 g/cm3 to a variation in the
output signal from 4 to 20 mA, with the vertical spacing
of the diaphragm seals equal to H = 3000 mm. The sealing
system is filled with DC-550 oil with density
H = 3000 mm roil = 1.068 g/cm3.
0.6 £ ρ [g/cm3] £ 1.2 1. Calculate the value of the start of the range as follows:
ρoil = 1.068 g/cm3 H[mm] × (Xrmin – Xroil) =
= 3000 × (0.6 – 1.068) = –1404 [mm H2O]
H

2. Calculate the value of the end of the range as follows:

H[mm] × (Xrmax – Xroil) =
= 3000 × (1.2 – 1.068) = 396 [mm H2O]
3. Set the zero point of the transmitter with the diaphragm
ρ seals positioned at the same level.
4...20 mA I 4. Install the transmitter in its working position.
5. Make the electrical connections to the transmitter,
DP
providing for the possibility of using HART
communication.

II/ 31
6. Connect the KAP-03 communicator, identify the Additional remarks
transmitter and select the “configuration” function. The settings of the transmitter can be adjusted with ref-
7. On the configuration menu select “Reranging” proce- erence to laboratory results from density measurements
dure. carried out on samples of the liquid being measured. This
8. On the “Reranging” menu: is most often necessary when the measurement takes
a) change the measurement units to mm H2O at 4°C; place in a pipeline segment where the flow velocity of the
b) enter the calculated values for the start (–1404) and measured liquid reaches several m/s.
end (396) of the range.
Increasing the vertical spacing of the diaphragm seals
When the transmitter has been configured in this way it is widens the range and often improves measurement
ready to be used to carry out the given measurement accuracy.
task.
In planning the spacing of the diaphragm seals, ensure
Note: If it is possible to fill the space between the seals that the pressure difference at the transmitter lies within
with a liquid whose density corresponds to the start of the the basic range.
measurement range, the start of the range of the trans-
The maximum vertical spacing of the diaphragm seals
mitter can be set using regulated pressure.
(H) depends on the transmitter’s basic range and the
boundary values for the density of the measured liquid
(rmin; rmax).
Measurement of phase boundary
The height of the phase boundary of liquids of different If rmin < roil < rmax, the seal spacing H should satisfy the
densities is determined by measuring the average densi- following conditions:
ty of the medium between the seals. lower boundary of range [mm H2 O]
H [mm] £
Xrmin - Xroil
Example:
Calculate the measurement range start and end points
upper boundary of range [mm H2O]
for an APR-2000/ALW transmitter configured to measure H [mm] £
phase boundary height in the range 0–1000 mm between Xrmax - Xroil
liquids of density r1 = 0.7 g/cm3 and r2 = 1.0 g/cm3,
Example:
where the vertical spacing of the seals H = 1600 mm.
Determine the maximum vertical spacing of the seals for
The sealing system uses DC-550 oil with a density of
the APR-2000ALW/-10...10 kPa transmitter when meas-
1.068 g/cm3.
uring the density of liquid between 0.6 and 1.2 g/cm3.
The sealing system uses AK-20 silicone oil with a density
of 0.945 g/cm3.
The lower boundary of the range of the transmitter is
–10 kPa = –1020 mm H2O
-1020 -1020
H [mm] £ Þ H [mm] £ Þ
0.6 - 0.945 -0.345
H = 1600 mm H [mm] £ 2957
0 £ h £ 1000 mm
ρ1 = 0.7 g/cm3 The upper boundary of the range of the transmitter is
H

ρ2 = 1.0 g/cm3 +10 kPa = 1020 mm H2O

ρoil = 1.068 g/cm3 ρ1
1020 1020
H [mm] £ Þ H [mm] £ Þ
1.2 - 0.945 0.255
H [mm] £ 4000
h

In the example, both conditions are satisfied when the

spacing of the seals is not more than 2957 mm.
4...20 mA I
DP
ρ2

To determine the start of the measurement range, calcu-

late the pressure difference at the transmitter when the
tank is filled with the lighter liquid only:
1600 [mm] × (0.7 – 1.068) = –588.8 [mm H2O]
To determine the end-point of the range, add the increase
in pressure resulting from the appearance of a 1 metre
column of the heavier liquid:
–588.8 [mm H2O] + (1.0 – 0.7) × 1000 [mm] =
= –288.8 [mm H2O]

II/ 32