How To Maintain Industrial Parts Washers Using Aqueous Detergents 

Originally Published: June 12, 2023 | Last Updated: December 19, 2023 | Contributor: Chris Jones (Global Business Development Manager, Brulin)

Cleanliness is a critical value-added aspect of precision parts manufacturing that ensures the quality of parts and components. Immersion parts washers, spray wash cabinets, rotary basket washers and ultrasonic tanks play a vital role in achieving this level of pristine cleanliness.

To keep these tanks functioning optimally, it’s essential to understand the intricacies of their maintenance. In this comprehensive and practical guide, we will delve into maintaining immersion parts washers that use aqueous detergents, specifically focusing on a wide range of aqueous alkaline and pH neutral process detergents.

If you want to receive official documentation, worksheets, and detailed step-by-step testing methodology outlines, contact our team and we’ll be happy to provide them.

From monitoring pH and concentration to assessing cleaning and corrosion performance, we will cover all the essential aspects to ensure your immersion washer is still a reliable part of your cleaning process. So, let’s dive in and explore the world of aqueous detergent immersion parts washers and ultrasonic tanks and how to ensure optimal performance and bath life.

This guideline is most relevant for wash tanks containing aqueous detergents.

Maintenance Guidelines For Parts Washers, Cabinets & Tanks Using Aqueous Detergents

Proper maintenance of immersion washers, spray wash cabinets and ultrasonic tanks is a fundamental aspect of ensuring optimal performance in your cleaning process. We’ve simplified this task by identifying three key parameters to keep your detergent solution in optimal condition:

• pH Monitoring: Regularly monitoring the pH level is essential to ensure the solution stays within the safe operational range of aqueous/alkaline detergents, thus maintaining the tank’s effectiveness.
• Concentration: Cleaning performance depends heavily on detergent concentration levels. Adjust as needed by adding detergent concentrate or water to achieve perfect balance.
• Performance (Cleaning & Corrosion): While pH and concentration are important indicators, the true test of your tank’s condition lies in its observed cleaning and corrosion performance. Make this the ultimate gauge of your tank’s overall health. 

By closely following these guidelines, you’ll be well on your way to maintaining a high-performing immersion tank, ensuring spotless results for every part that goes through the cleaning process.

pH Monitoring Guide

As an expert in tank maintenance, we understand the importance of frequent pH checks to ensure the highest cleaning performance. Here’s a detailed approach to mastering the pH aspect of your tank’s maintenance routine:

1. Daily pH Monitoring: Make it a habit to check the pH at least once a day, although high-throughput or continuous-use systems might require more frequent monitoring. Precision pH paper or digital pH meters are excellent tools for this task.
2. Maintaining Optimal pH: For cleaning aluminum with alkaline detergents, keep the pH above 9.5 to prevent corrosion. For other substrates, aim for a pH above 9.0. If the pH falls below the control limit, consider changing the tank’s detergent solution.
3. Adapting to Specific Conditions: The true minimum pH for acceptable performance varies depending on factors such as corrosion tolerance, detergent type, concentration level, process conditions, and aluminum alloy types. By closely monitoring cleaning and corrosion performance, you may extend tank life by allowing lower control limits than typically recommended.
4. pH Neutral Detergents: For aqueous pH-neutral detergents, there’s no control limit. Instead, use pH checks to ensure consistency in tank conditions.

Once you’ve recorded the pH, move on to the Concentration check.

Concentration Check Guide

Here’s our definitive guide to performing concentration checks:

1. Consistent Monitoring: Check detergent concentration at the same intervals as pH monitoring, using either the drop-counting method or standard laboratory burette titration method.
   • Drop-Counting Method: Ideal for use on the factory floor, this convenient approach requires a titration kit. Don’t hesitate to contact our specialists to obtain one. For this method, you’ll record the Sample Size (mL), HCl Acid (N), Indicator (drops), and Correction Factor.
   • Burette Titration Method: If you have access to a laboratory (burette, pH meter, mixer, etc.), opt for this more precise method. For this method, you’ll record the Sample Size (mL), HCl Acid (N), End Point, and Correction Factor.
2. Setting Targets: Establish a target detergent concentration and control range based on your cleaning process or client specifications. For Brulin aqueous detergent products, consult the product brand sheet for each process detergent for typical dilution ranges.
3. Control Range: Start with a control range of +/- 2.0% of the target value. For example, if the target is 10%, use 8 – 12% as the control range.
4. Cleaning Aluminum: Ensure the lower control limit is above the minimum recommended concentration specified in the product information. For alkaline detergents, a 5% concentration lower limit is generally safe for aluminum; for pH-neutral detergents, there’s no required concentration lower limit for aluminum applications.

Concentration Control

A range of factors can cause the concentration to fluctuate, such as detergent consumption by soils, acidity in the soils, evaporation of water, and liquid “dragout” with washed parts.

Monitor the detergent concentration and liquid level in your tank and determine whether they need to be corrected by adding detergent concentrate and/or process water. To avoid any mishaps, we recommend first applying the necessary adjustments to a small tank sample (e.g., 100 mL) and then verifying that the pH of the adjusted sample is within the acceptable range.

After adjusting the detergent concentrate and/or liquid level in your tank, re-test and record the pH and concentration of the adjusted tank to ensure everything is in order before continuing to the performance check.

Cleaning & Corrosion Performance Check Guide

Keeping your parts washers in top shape involves more than just monitoring pH and concentration. It’s essential to assess cleaning and corrosion protection efficacy as well. Here’s how to conduct a comprehensive weekly performance check like a pro:

1. Establish Standard Methods – We strongly recommend implementing a standard method for weekly performance checks to verify cleaning and corrosion protection effectiveness in your operation.
2. Choose Representative Test Pieces – Select test pieces that accurately represent the soil type, soil loading, material/alloy type, and sensitivity to corrosion found in your actual wash operation.
3. Set Pass/Fail Criteria – Decide the criteria for cleanliness and corrosion protection that align with the requirements of your parts.
4. Select Suitable Test Methods – Use the right test methods for your operation, such as proven, relevant, and/or validated methods. If no specific methods have been designated, consider the “water break test” for cleanliness and visual inspection for corrosion protection (comparing against a reference sample).
5. Take Action – If performance does not meet the required criteria, change out the detergent, regardless of concentration or pH measurements.

By following these guidelines, you’ll ensure your tank consistently delivers exceptional cleaning and corrosion protection, keeping your operation running smoothly.

Additional Considerations For Emptying & Recharging Detergent

Striking the right balance between maximizing the service life of your detergent tank and ensuring optimal performance is an essential part of maintaining your immersion parts washer or ultrasonic tank. As seasoned parts cleaning experts and advisors, we at Brulin are here to guide you in making informed decisions about your precision parts cleaning needs.

The key factors determining the detergent’s lifespan include soil loading, soil type, throughput, substrate type, and the specific process setup of your operation. Due to the complexity of these factors, it’s impossible to predict the exact lifespan of your detergent tank without testing it under actual use conditions.

Once you’ve established the service life of your detergent, this becomes a valuable benchmark. With consistent conditions, the tank life should remain stable from one recharge to the next. Keep in mind, though, that any changes in parts, soils, throughput, or operational conditions will affect the detergent tank life.

To stay on top of tank maintenance, maintain detailed records of change-out frequency for each operational unit. When concentration, pH, and performance checks suggest it’s time for a change, verify that the age of the detergent is within the expected range.

At Brulin, we pride ourselves on being your trusted advisor in all industrial parts cleaning topics. No matter what questions or concerns you may have about precision parts cleaning, we’re here to help you navigate the complexities of tank maintenance and achieve exceptional results. Reach out to us and our experts would be happy to guide you to a better process.