Integral high‑pressure water prism wash is recommended to be used in applications where conventional wash (see Prism wash with integral steam nozzle) is insufficient to remove coating. It can be used for example in the measurement of starch, beer worth, green liquor in the wood pulp industry or directly after the evaporation in the sugar industry.
Figure 1 describes the recommended components for a prism wash system with integral high pressure water nozzle. The components can be supplied by Vaisala.
Note the following items in the high pressure wash system:
- Integral water wash nozzle (HPN) is built on a sensor which has a Sandvik clamp or a flange connection.
- For mounting a flow cell see Prism wash with flow through cells.
- Check valve PR‑3303 is recommended to all washing applications.
- The high pressure pump should be able to keep a pressure of 100 bar for a 1.25 mm (0.05 in) diameter nozzle.
- For recommended wash pressures and times, see Recommended wash pressures and times.
High‑pressure pump
Use Vaisala PR‑3602‑SP‑400 high pressure pump. The recommendation is to use 3 (3 phase) pumps with local voltages. Inlet water temperature should be warm, about +60 °C (+140 °F). Vaisala delivers high pressure pump with 8 m rubber high‑pressure hose. Customer can also make high pressure line between pump and nozzle from stainless steel pipes which are suitable for pressures up to 150 bar. With stainless steel pipes it is recommended to use heat trace and insulation to keep washing water warm at +60 … +70 °C (+140 … +158 °F).
| Pressure increase can occur in a closed pipe section when the high pressure pump is operated. It is recommended to mount a pressure relief valve in the pipe section. Relief pressure should be according to pipe pressure rating. |
The DTR (indicating transmitter) relay is used to drive the power relay unit PR‑3603‑400. The power relay unit drives the high‑pressure pump and the water valve. Pump relay has an overload relay which will switch off the pump if current goes over the set limit. The configuration of the relay is done through the indicating transmitter keyboard. For the wiring of the high‑pressure components, see Figure 2.
| Part | Part specification | Supplied by | Qty |
|---|---|---|---|
| 1 | Indicating transmitter DTR | Vaisala | 1 |
| 2 | Sensor PR‑21‑xxx‑HPN | Vaisala | 1 |
| 3 | Cable between indicating transmitter and sensor PR‑8230 | Vaisala | 1 |
| 4 | Check valve R ¼ in PR‑3303 | Vaisala | 1 |
| 5 | High‑pressure hose 8 m (26.25 ft) | Vaisala | 1 |
| 6 | AC power supply 230/110 V | Customer | 2 |
| 7 | Power relay unit PR‑3603‑400‑U/M‑230/110/24 | Vaisala | 1 |
| 8 | High‑pressure pump PR‑3602‑400‑BR/SS‑230/110 including water valve | Vaisala | 1 |
| 9 | Power supply cable 3 m (9.84 ft) for water valve | Customer | 1 |
| 10 | Power supply cable 3 m (9.84 ft) for high‑pressure pump | Vaisala | 1 |
