Recommended Wash Pressures And Times; Prism Wash Systems - Vaisala K-PATENTS PR-23 Series Instruction Manual

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4.2.1 Recommended wash pressures and times

The recommended wash pressures and times are given in the tables below.
Wash medium parameters for integral wash nozzles in PR-23-AP/GP
Steam (SN)
Water (WN)
High pressure water (WP)
Steam (SN)
Water (WN)
High pressure water (WP)
Wash medium parameters for Safe-Drive Isolation valve nozzle SDI
Steam (SN)
High pressure water (WP)
Important: In steam wash, do not exceed the recommended wash times, because
some process media may burn to the prism surface if steamed for longer time. In case
of coating, shorten the wash interval.
See also Section 6.5.2 for the Automatic wash cut parameter.
Note: In water wash, water temperature should be above the process temperature.
Note: The check valve pressure drop is 0.7 bar (10 psi).

4.2.2 Prism wash systems

The prism wash system for steam is described by Figure 4.1 and for sanitary systems
Figure 4.2. The prism was system for high pressure water is described by Figure 4.6
and for sanitary systems Figure 4.7.
Warning! In high pressure wash systems, pressure increase can occur in a closed
pipe section when the high pressure pump is operated. The recommendation is to
mount a pressure relief valve in the pipe section. Relief pressure should be according
to pipe pressure rating.
Minimum above
process pressure
2 bar (30 psi)
2 bar (30 psi)
15 bar (220 psi)
Wash medium parameters for flow cell wash nozzle AFC
Minimum above
process pressure
3 bar (45 psi)
3 bar (45 psi)
25 bar (350 psi)
CONC % value Minimum above
process pressure
10–30 % 2 bar (30 psi)
30–60 % 3 bar (45 psi)
60–90 % 4 bar (60 psi)
20 bar (290 psi)
PR-23 instruction manual
Maximum above Wash Recovery Interval
process pressure time
4 bar (60 psi) 3 s 20–30 s 20–30 min
4 bar (60 psi) 10 s 20–30 s 10–20 min
40 bar (600 psi) 10 s 20–30 s 10–20 min
Maximum above Wash Reco-
process pressure time
6 bar (90 psi) 3–5 s 20–30 s 20–30 min
6 bar (90 psi) 10–15 s 20–30 s 10–20 min
35 bar (500 psi) 10–15 s 20–30 s 10–20 min
Maximum above Wash Reco-
process pressure time very
4 bar (60 psi) 2–3 s 20 s 120–360 min
6 bar (90 psi) 3 s 20 s
8 bar (120 psi) 3–5 s 20 s
30 bar (435 psi) 10–15 s 20 s
Interval
very
Interval
20-60 min
15-25 min
5–20 min