Detail
Temperature-Compensated Surface Blowdown Control
The VIRA D-BS4-T is designed for steam boiler applications where operating temperature and pressure may vary. It continuously monitors boiler-water conductivity and controls surface blowdown to help maintain the required TDS range, protect steam quality and reduce unnecessary water, heat and treatment-chemical losses.
Why Temperature Compensation Matters
Boiler-water conductivity changes with temperature. In conventional conductivity measurement, these changes can affect the measured value and require the boiler to operate at stable conditions for reliable calibration. D-BS4-T uses temperature-compensated conductivity measurement to reduce the influence of changing operating temperature on the control process.
D-BK 5000-T New-Generation Controller
The system uses the D-BK 5000-T controller, operating with a 24VDC supply. Its touchscreen interface supports clear monitoring and practical adjustment of conductivity set point, hysteresis, high-conductivity alarm and blowdown control settings. The controller can be installed on a DIN rail or mounted on a control panel, providing flexibility for new installations and modernisation projects.
Monitoring and System Integration
D-BK 5000-T provides valve control and alarm functions together with 4–20 mA conductivity information and RS485 Modbus communication. This allows the boiler-water conductivity value and blowdown status to be incorporated into a wider boiler-room monitoring or automation system where required.
BD 5600-T Temperature-Compensated Conductivity Probe
Conductivity and temperature are measured by the BD 5600-T probe. Its integrated temperature sensing enables the control system to compensate conductivity measurement according to the actual boiler-water temperature. The probe can be manufactured in project-specific lengths to suit the boiler connection and installation requirements.
DG 5400 Probe Body
The BD 5600-T probe is installed with the DG 5400 probe body to ensure correct positioning and reliable contact with boiler water. DG 5400 is available in sizes compatible with the selected BKV 5400 blowdown valve, enabling the measuring and blowdown components to be matched to the boiler connection size.
BKV 5400 Surface Blowdown Valve
The BKV 5400 surface blowdown valve controls the discharge of boiler water when conductivity exceeds the configured limit. It is available in DN 20, DN 25 and DN 40 sizes, all with a PN 40 pressure class. The valve has a WCB body, metal-to-metal sealing and a sampling outlet located below the valve.
Actuator Options for the Application
BKV 5400 can be supplied with either a pneumatic actuator or an electric actuator, allowing the valve configuration to be selected according to the available utility supply, control philosophy and project requirements.
Controlled TDS Management for Efficient Steam Production
When the measured conductivity reaches the selected limit, D-BS4-T operates the blowdown valve until the value returns to the required range. This supports stable boiler-water conditions, helps reduce carryover and deposit risk, and avoids excessive blowdown that can waste energy, treated water and chemicals.
| Supply Voltage | 24 VDC |
| Control Functions | Automatic TDS blowdown, conductivity set point, hysteresis, high-conductivity alarm, on-off valve control and calibration |
| Inputs | Conductivity probe, PT100 temperature sensor, ground |
| Outputs | 1 on-off valve relay, 1 alarm relay, 4–20 mA analogue conductivity signal and RS485 Modbus communication |
| Display & Operation | Touchscreen interface |
| Mounting & Protection | Panel-mounted or DIN-rail mounted PC enclosure, IP40 |
| Maximum Ambient Temperature | 55 °C |
| Process Connection | Threaded connection; BSPT option available |
| Probe Length | 500 mm standard; project-specific length specified at the time of order |
| Pressure Rating | PN40; maximum operating pressure 32 bar(g) |
| Temperature Limits | Maximum operating temperature 239 °C; maximum ambient temperature 75 °C |
| Integrated Sensor | PT100 temperature sensor |
| Nominal Size | DN20, DN25 and DN40 |
| Pressure Rating | PN40 |
| Body & Sealing | WCB carbon-steel body with metal-to-metal sealing |
| Actuation | Electric on-off or pneumatic spring-to-close actuator |
| Electrical Actuator Supply | 220 VAC; 24 VDC available on request |
| Operating Temperature | −10 to +230 °C |
| Sample Connection | Sample outlet at the bottom of the valve |
| Function | Provides a suitable mounting point and reliable boiler-water contact for the conductivity probe |
| Nominal Size & Pressure Rating | DN20, DN25 and DN40; PN40 |
| Operating Limits | Maximum operating pressure 32 bar(g); maximum operating temperature 239 °C |
| Body Material | Ductile cast iron or carbon steel |
