PEE1V03
20-11- 2017
8
G1 ¼“
3,2
DN25
5,6
G2“
3,7
DN40
6,8
DN50
8,5
DN65
13
DN80
15
DN100
18
Environmental class
Meets EN1434 class C
Ambient temperature:
Calculator
at +5
o
C to +55
o
C
(condensing, indoor installation)
Flow sensors
at -30
o
C to 55
o
C
Relative humidity
< 93
Mechanical environment class:
M1
Electromagnetic environment class:
E2
Protection class of calculator enclosure
IP65
Protection class of flow sensor enclosure
IP65 (IP67
– by special ordering)
3. OPERATING PRINCIPLE
The flow measuring principle is based on ultrasonic measurement method. The ultrasonic signal along the
measuring section moves many times before, and the flow downstream between the ultrasonic sensors have to
perform transmitter and receiver functions. From the resulting time difference the flow rate is calculated.
The liquid temperature is measured with standard platinum resistance temperature sensors Pt500 or
Pt1000. Pairs of temperature sensors with 2-wire connection method for measurement temperatures on flow and
return pipelines are used. Flow and return temperature sensors can be replaced only in pairs.
Energy calculation formulas:
- Flow sensor in flow pipe
Q = V1
ρ
1
(h
T1
-h
T2
)
- Flow sensor in return pipe
Q = V1
ρ
2
(h
T1
-h
T2
)
There: Q
–thermal energy,
V1
–Water volume, m
3
ρ
1
ρ
2
–
Water densities, according
to supplied and return
water temperatures
1,
2
h
T1,
h
T2
– The enthalpies, according to water temperatures
1,
2
When function of cooling energy is made active and at negative temperature difference, the energy for
cooling will be registered and in the additional tariff register:
∑ Q = Q 1 + Q 2
- Flow sensor in flow pipe:
When
Θ1 > Θ2: Q1=V1
1
(h
T1
-h
T2
), Q2=0
When
Θ1< Θ2: Q2=V1
1
(h
T2
-h
T1
), Q1=0
- Flow sensor in return pipe:
When
Θ1 > Θ2: Q1=V1
2
(h
T1
-h
T2
), Q2=0
When
Θ1< Θ2: Q2=V1
2
(h
T2
-h
T1
), Q1=0
Heat meter calculator provides all the necessary measurements and data storage functions.
4. MARKING AND SEALING
4.1.Marking
Calculator
There are following information on the front panel of calculator -
manufacturer’s trade mark , type of meter,
serial number, year of manufacture, EC-type examination certificate number, limits of the temperature, limits of the
temperature differences, accuracy class, environmental class by LST EN1434-1, electromagnetic and mechanical
environmental class, enclosure protection class, type of temperature sensors, flow sensor installation site (flow or
return pipe), the limiting values of the flow rate(qi,qp,qs), maximum temperature range for flow sensor , the
maximum admissible working pressure, nominal pressure, voltage level for power supply and logo of distributor (if
applicable).
