Prism wash with integral steam nozzle is for use in applications where steam can remove
coating from pipe lines. For other applications see Prism wash with integral high-pressure water nozzle and Prism wash with flow through cells. The integral nozzle is
mounted on the sensor head (see Figure 1). Integral
steam nozzle (HPS) can be equipped for a long probe sensor with standard insertion length
(LPS) and with the following process connections:
Sandvik L‑clamp, 80 mm
ANSI‑flange 150 lbs
DIN flange 2556, PN25, DN 80
JIS flange, 10 K 80 A
The earlier mentioned sensors are equipped with an integral nozzle connection (HPY) as a
standard. An integral steam nozzle can be easily fitted afterwards, if required. Figure 2 shows
recommended components for a prism wash system with integral steam nozzle. The components are
provided by Vaisala. The steam line should be equipped with a check valve (see Figure 2). If the
process medium solidifies at ambient temperature, the check valve should be insulated (see
Figure 2). A condensate trap should be used to keep the steam line hot (see Figure 2).
Alternatively, an external timer can be used. The timer should be equipped with extra contact
which is kept closed during prism washes.
WARNING Do not connect the extra contact to external voltage. For recommended wash
pressures and times see Recommended wash pressures and times.
In intrinsically safe system solenoid valves are mounted in the safe area and the
pneumatic valves in hazardous area.
Figure 1. Mounting of integral steam nozzles with
DIN, JIS, ANSI and Sandvik connections
Figure 2. Mounting summary of integral prism wash
system
Part
Part specification
Supplied by
Qty
1
Indicating transmitter DTR
Vaisala
1
2
Sensor PR‑21‑S
Vaisala
1
3
Cable PR‑8023 between indicating transmitter and sensor
