electronic pressure-independent characterised control valve Table of contents The electronic characterised control valve () Project planning 4 Selection and dimensioning 5 Constant flow volume V 5 Valve design 5 Verification of the differential pressure 6 Design on missing hydraulic data 6 Flow characteristics 6 Dimensional diagram for EV DN 15...50 8 Application 8 Media 8 Medium temperature 8 Dimensional diagram for EV DN 65...150 9 Application 9 Media 9 Medium temperature 9 www.belimo.com en-gb 019.03 Subject to changes 1 / 1
The electronic characterised control valve () Structure Nominal diameter DN 15...50 Nominal diameter DN 65...150 3 3 1 1 1. Characterised control valve (leakage rate A according to EN 166-1) Air bubble-tight sealing regulating device ensures absolutely sealed shutting at zero load and thus reliably prevents activation losses. Measuring pipe with volumetric flow sensor Optimally adapted to the requirements of the ultrasonic flow measurement field of application 3. Actuator Actuator specially optimised for pressure-independent flow control Mode of operation The control device consists of three components: characterised control valve, measuring pipe with volumetric flow sensor and the actuator. The set maximum flow (V max ) is allocated to the maximum positioning signal (typically V / 0%). The control device can be communicative or analogue controlled. The medium is recorded by the sensor in the measuring pipe and is applied as the flow rate value. The measured value is compared with the setpoint (analogous to positioning signal or requirement via bus communication). The actuator corrects the deviation by changing the valve position. The angle of rotation α varies according to the differential pressure through the control element. V p1 < p < p3 p3 p V p1 α Transfer response of the heat exchanger Depending on the construction, temperature spread, medium and hydraulic circuit, the power Q' is not proportional to the water volumetric flow V (Graph 1). In classical temperature control, it is attempted to keep the positioning signal Y proportional to the power Q' (Graph ). This is achieved by means of an equal percentage valve characteristic curve (Graph 3). 1 3 Y For applications with linear transfer behaviour (a-value ~1) the flow characteristic of the can be changed from equal percentage to linear. / 1 en-gb 019.03 Subject to changes www.belimo.com
The electronic characterised control valve () (continuation) Control characteristics The velocity of the medium is measured in the measuring component (sensor electronics) and converted to a flow rate signal. The positioning signal Y corresponds to the power Q' via the exchanger. The volumetric flow is controlled in the. The positioning signal Y is converted into an equal percentage volumetric flow characteristic curve and provided with the V' max value as the new reference variable w. The momentary control deviation forms the positioning signal Y1 for the actuator. The specially configured control parameters in connection with the precise flow rate sensor ensure a stable quality of control. It is however not suitable for rapid control processes, i.e. for domestic water control. U5 displays the measured volumetric flow as voltage (factory setting). As an alternative, U5 can be used to display the valve opening angle. Y A 1) D A U5 D 1) w PP/MP D A DN k V Y1 M www.belimo.com en-gb 019.03 Subject to changes 3 / 1
Project planning Relevant information Dimensions Pipeline clearances -way version Direction of flow Water quality Strainer Design water system Shut-off devices Definitions The data, information and limit values listed on the electronic pressure-independent characterised control valve () data sheets are to be taken into account and/or complied with, respectively. EP..R+MP (DN 15...50 with standard actuator) EP..R+KMP (DN 15...50 with electrical emergency control function) EP..R+MOD (DN 15...50 with modbus actuator) EP..F-MP (DN 65...150 with standard actuator) EP..F-KMP (DN 65...150 with electrical emergency control function) EP..F-MOD (DN 65...150 with modbus actuator) P6..W..E-MP (DN 65...150 with standard actuator) P6..W..E-KMP (DN 65...150 with electrical emergency control function) P6..W..E-MOD (DN 65...150 with modbus actuator) The dimensions of the actuator combination used depend on the design and nominal diameter used. The dimensions are listed on the data sheets. The minimum clearances between the pipelines and the walls and ceilings required for project planning depend not only on the valve dimensions but also on the version. The dimensions can be found on the corresponding data sheet. -way s are throttling devices. The installation in the return is recommended. This leads to lower thermal loads on the valve. The specified direction of flow must be observed. The water quality requirements specified in VDI 035 must be adhered to. The is a regulating device. So that the control task can be taken over in the long term, central strainers are recommended in the system. Application is permitted only in closed water circuits. Care must be taken to ensure that sufficient numbers of shut-off devices are installed. V nom is the maximum possible flow. V max is the maximum flow rate which has been set with the greatest positioning signal, e.g., V. V max can be set between 30% and 0% of V nom (DN 15...50). V max can be set between (30)45% and 0% of V nom (DN 65...150). V min 0% non-variable. V [m 3 /h] 0% V nom 30% V max 0 Y [V] 0% 4 / 1 en-gb 019.03 Subject to changes www.belimo.com
Design and dimensioning A conventional (pressure-dependent) valve is designed based on the kv value. For a given nominal flow, this is dependent on the differential pressure which is present across the valve. In order to obtain a sufficient quality of control, the valve authority Pv must also be taken into account for pressure-dependent valves. For a pressure-independent solution, such as the, the design is greatly simplified. Due to the automatic adjustment of flow deviations, the always provides the required water quantity even with differential pressure fluctuations and during partial load operation. Due to this dynamic adjustment, the valve authority amounts to 1. Constant flow volume V' Due to the permanent balancing of the measured flow value with the setpoint and the corresponding automatic readjustment of the valve opening position, a constant, pressureindependent water quantity is ensured over a large differential pressure range. 150 V [l/min] V max = nominal flow V nom (catalogue value) Control requirement 0% (e.g. V) 0 0 00 300 350 p [kpa] Pressure-independent flow over a large differential pressure range due to dynamic balancing (example EP040R+MP) Valve design The valve is determined using the maximum flow required V max. A calculation of the kvs value is not required. The required system specific maximum flow V max must lie within the permissible setting range of the. DN 15...50: V max = 30 0% of V nom (data sheet value) DN 65...150: V max = (30)45 0% of V nom (data sheet value) During commissioning, the desired system-specific flow rate value V' max is set on the valve using the ZTH EU adjustment tool, software PC-Tool or via bus. 150 V [l/min] = nominal flow V nom (catalogue value) Control requirement 0% (e.g. V) 75 V max = 50% V nom (setting) Control requirement 0% (e.g. V) 0 0 00 300 350 p [kpa] System specific setting of the maximum flow V max (example EP040R+MP) www.belimo.com en-gb 019.03 Subject to changes 5 / 1
Design and dimensioning (continued) Verification of the differential pressure For proper operation, the differential pressure across the valve must lie within a defined range. Minimum differential pressure (minimum pressure drop) The minimum required differential pressure (pressure drop across the valve) to reach the desired volumetric flow V' max can be calculated with the theoretical kvs value (see data sheet) and the formula below. The calculated value depends on the required maximum volumetric flow V' max. Higher differential pressures are compensated for automatically by the valve. Formula: p min = 0 x V max k vs theor. p min : kpa V max : m 3 /h k vs theor. : m 3 /h Example (DN 5 with the desired maximum flow = 58% V nom ) EP05R+MP kvs theor. = 8.6 m 3 /h V nom = 69 l/min 58% * 69 l/min = 40 l/min =.4 m 3 /h p min = 0 x V max k vs theor..4 m 3 /h = 0 x = 8 kpa 8.6 m 3 /h Maximum differential pressure Higher differential pressures across the valve are compensated for automatically by this. A movement of the closing element in the direction of the closing point causes an increase in the pressure drop across the valve. This ensures a constant water quantity. The permitted maximum differential pressure is specified on the data sheet. Design on missing hydraulic data Flow characteristics If no hydraulic data are available, then the same valve DN can be selected as the heat exchanger nominal diameter. In the case of an electronic pressure-independent characterised control valve, the positioning signal requirement corresponds directly to a flow value. The offers various setting options with which the characteristic curve can be influenced: Characteristics of the characteristic curve equal percentage optimised with a characteristic curve factor n(gl) = 3., in the opening range(*) (factory setting) linear Operating range Y DC... V (factory setting) Starting point DC 0.5...4 V / End point DC 8.5...3 V Adjustable flow DN 15...50: 30...0% of V nom DN 65...150: (30)45...0% of V nom Factory setting V`max = 0% of V nom Inverting positioning signal no (factory setting) yes (*) The course is linear in the lower opening range between 0 30% stroke. This ensures outstanding control characteristics, including in the lower partial load range. Flow rate curve (factory setting) 6 / 1 en-gb 019.03 Subject to changes www.belimo.com
Design and dimensioning (continued) V [l/min] (= 0% V nom) 0 Y [V] Flow rate curve-settings: V max reduced V [l/min] (= 70% V nom) 0 Y [V] Flow rate curve-setting: linear characteristic Operating range 0.5... V V [l/min] (= 0% V nom) 0 Y [V] www.belimo.com en-gb 019.03 Subject to changes 7 / 1
Dimensional diagram for DN 15...50 Application Media Medium temperatures This control device is used in closed cold and warm water systems for continuous water-side control of air handling units and heating systems. Cold and warm water, water with glycol up to max. 50% vol. The permissible medium temperatures can be found in the corresponding data sheets. V max [m 3 /h] 50 40 30 0 0.5 0.4 0.3 0. pmin [kpa] 8 6 5 4 0.1 0.08 0.06 0.05 0.04 pmin [bar] 3 0.03 0.0 0.08 0.11 0.14 0.17 0. 0.8 0.6 0.8 1.1 1.4 1.7..8 0.3 0.4 0.5 0.6 0.8 1 3 4 5 6 8 0 DN 15 DN 0 DN 5 DN 3 DN 40 DN 50 6 V max [l/s] p min The minimum required differential pressure (pressure drop across the valve) to reach the desired volumetric flow max Desired volumetric flow should be achieved at full load. Flow at greatest positioning signal, e.g. V p min = 0 x V max k vs theor. p min : kpa V max : m 3 /h k vs theor. : m 3 /h 8 / 1 en-gb 019.03 Subject to changes www.belimo.com
Dimensional diagram for DN 65...150 Application Media Medium temperatures This control device is used in closed cold and warm water systems for continuous water-side control of air handling units and heating systems. Cold and warm water, water with glycol up to max. 50% vol. The permissible medium temperatures can be found in the corresponding data sheets. V max [m 3 /h] pmin [kpa] 0 80 60 50 40 30 0 0 30 DN 65 40 50 60 DN 80 80 0 DN 0 DN 15 00 DN 150 0.8 0.6 0.5 0.4 0.3 0. pmin [bar] 8 0.1 0.08 6 5 0.06 0.05.8 6 8 11 14 17 8 60 300 80 V max [l/s] p min The minimum required differential pressure (pressure drop across the valve) to reach the desired volumetric flow max Desired volumetric flow should be achieved at full load. Flow at greatest positioning signal, e.g. V p min = 0 x V max k vs theor. p min : kpa V max : m 3 /h k vs theor. : m 3 /h www.belimo.com en-gb 019.03 Subject to changes 9 / 1
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