Realtech REAL CLEAN SYSTEM I - Cleaning; Table 3: Commercial Cleaning Solutions; Figure 7.1: Effective Cleaning; Figure 7.2: Inadequate Cleaning

Real Clean System I v 2.1
Real Tech Inc. 13
7 Cleaning
The Real Clean system comes with a 1L chemical storage bottle. After
a cleaning cycle, approximately 85% of the used cleaning fluid is
pumped back into the bottle reducing the need to replenish the fluid
on a regular basis.
Two important factors that affect the sensor performance are the
cleaning fluid used to clean the flow cell, and how often the flow cell
is cleaned (cleaning frequency).
Cleaning Frequency
The optimum frequency of cleaning is quite variable depending on
the amount and type of fouling agents in the water. This will be
dependent on the application and installation point.
For wastewater, a higher frequency will be required (ex. 1-24hrs)
whereas high purity water will require a lower frequency (ex. once a
month). Each installation will be different and require configuration
onsite.
Once in operation, observe the flow cell for signs of fouling prior to
the first cleaning cycle. If fouling is present, increase the cleaning
frequency accordingly. The measured data can also be observed for
signs of a saw tooth effect as shown in Figure 7.1. If the saw tooth
shows an upward trend, as shown in Figure 7.2, the sensor is drifting
and cleaning frequency must be increased.
Cleaning Fluid
Selecting an effective cleaning solution is essential for optimal
performance. The following commercial cleaning solutions and acids
are readily available to remove common fouling agents.
Table 3: Commercial cleaning solutions
SOLUTION
FOULING AGENTS
Lactic Acid <20% solution (CLR®)
Removes lime, calcium, rust, magnesium, and other dissolved minerals
Sulfamic Acid <10% solution (Lime Away®)
Removes lime, calcium, rust, magnesium, and other dissolved minerals
Phosphoric Acid <30% solution (Rust Off,
Hagasen Blue)
Removes lime, calcium, rust and color staining
Citric Acid <20% solution
Removes mineral scaling
Sodium Hypochlorite <6% solution (Not bleach)
Removes oil, grease and biofilm
Acetic Acid <20% solution
Removes oil and grease
Sulfuric Acid <10% solution
Removes oil and grease
Figure 7.1: Effective cleaning
Figure 7.2: Inadequate cleaning