Hamilton Memosens® pH Sensors for Process Analytics

Specifications

*Note: The maximum operating temperature is restricted in Ex areas. For T3, it is limited to 130°C; for T4, to 120°C; and for T6, to 70°C.

A = Autoclavable; S = Sterilizable; CIP = Cleaning in Place

Intended Use

These sensors are designed for pH measurement. If used in areas with potentially explosive atmospheres, the instructions in the section "Use in Potentially Explosive Atmospheres" must be strictly followed. The integrated temperature sensor is intended solely for pH value compensation and not for process temperature control or regulation.

Safety Instructions

• Handle sensors with care, as they are made of glass. Broken glass can cause injury. Sensors with a pressurized reference system (e.g., EasyFerm Plus) carry an additional risk of spontaneous breakage, potentially scattering glass splinters. Protective eyewear is recommended when working with these sensor types.
• Wear protective eyewear and gloves when cleaning or regenerating sensors with acids, bases, or solvents.
• Ensure the PG 13.5 thread and the O-ring are not damaged when screwing the sensor into the process.
• O-rings are wear parts and must be replaced regularly, at least once a year.
• Always adhere to the specified temperature limits.

Liability

Hamilton Bonaduz AG's liability is governed by its "General Terms and Conditions of Sale and Delivery" (AVB), specifically Chapter 12. Hamilton is not liable for direct or indirect damages arising from the use of these sensors. Malfunctions may occur due to the inherent, application-dependent limited lifespan of sensors. The user is responsible for calibration, maintenance, and timely replacement of sensors. For critical applications, Hamilton recommends using redundant measuring points to prevent consequential damages. The user is responsible for implementing appropriate safety measures in case of sensor failure.

Memosens® System: Contact-free, Inductive, Digital Transmission of pH Values

The Memosens® system eliminates contact corrosion and interference from stray potentials through galvanic isolation between the sensor and transmitter. It is also completely waterproof. Storing data within the sensor allows for easy calibration and adjustment in a laboratory setting, followed by a simple sensor swap in the process, with the new sensor being automatically recognized. This system ensures reliable and flexible pH measurement in demanding process environments.

Data Stored in Sensor:

• Manufacturing Data: Reference Number (Ref), Serial Number, Date of Manufacture
• Calibration Data: Calibration Date, Slope and Zero Point at 25°C, Temperature Offset, Number of Calibrations
• Operating Data: Operating Hours, Date of First Use, Operating Hours at Temperatures above 80°C / above 100°C, Operating Hours at Very Low / Very High pH Values (Nernst voltage >+300 mV or <-300 mV), Number of Sterilizations, Glass Membrane Impedance (pH sensors only)

All stored data can be read using a Memosens®-compatible transmitter or specialized PC software. When a sensor is connected to a Memosens®-compatible transmitter via a Memosens® data cable, sensor data is automatically transferred and used for pH value calculation. Storing calibration data in the sensor enables calibration at an optimal location, such as a lab, or at the measuring point as usual. The collection of operating data facilitates preventive maintenance.

Initial Operation

Upon unpacking, inspect the sensor for any damage. Damaged sensors should be returned to the Hamilton dealer in their original packaging.

Preparing the Sensor:

• Carefully remove the watering cap.
• Rinse the sensor with water.
• Check the interior of the pH glass membrane for air bubbles. Gently shake the sensor to allow any bubbles to rise to the top.

For Refillable Sensors:

Open the reservoir stopper before measuring and close it again after measuring. Check the electrolyte level.

Connecting Sensor to Memosens® Cable

The Memosens® data cable ensures a secure and waterproof connection. The connection process involves aligning specific notches on the cable coupling with the sensor head, inserting the coupling, and then rotating the lower part of the coupling clockwise by approximately 60 degrees until it locks. This mechanism prevents accidental disconnection. Disconnection is performed in the reverse order. This contactless inductive transmission of measured values eliminates moisture-related issues, providing protection up to IP68 (10m water column for 45 days in 1M KCl). Connections can even be made underwater.

Start-up Behavior

After connecting a new sensor and powering on the transmitter, communication is established within seconds, and a real-time measurement value is displayed. The process involves: communication establishment (approx. 1 second), sensor data exchange (approx. 3 seconds), and measured value display (approx. 3 seconds), followed by process data collection.

Calibration

Always use fresh, unused Hamilton DuraCal pH buffers for calibration and adjustment. For detailed procedures, consult the documentation for the specific transmitter being used.

Storing the Sensor

Sensors should be stored with the watering cap in place, filled with 3M KCl solution (Ref 238036) or storage solution (Ref 238931). Sensors stored dry may exhibit temporary drifting values. If a sensor dries out, it can be regenerated by placing it in storage solution overnight.

Cleaning

General Cleaning:

Sensors with glass shafts can be briefly cleaned with acids, bases, or common solvents, followed by rinsing with water. After cleaning, sensors may show temporarily extended response times and should therefore be placed in storage solution for at least 15 minutes.

Ceramic Diaphragms:

For protein contamination, immerse the sensor for several hours in a solution of 0.4% HCl + 5 g/l Pepsin. If the diaphragm appears blackened (due to silver compounds), immerse the sensor in 0.4% HCl + 76 g/l Thiourea. The Cleaning Solution Set (Ref 238290) is available to address these issues.

Regeneration

Immerse the sensor for 10 minutes in 0.1-1M NaOH, followed by 10 minutes in 0.1-1M HCl. After regeneration, place the sensor in storage solution for 15 minutes.

Disposal

Hamilton sensors are designed with environmental compatibility in mind. Memosens® sensors contain electronic components that must be disposed of as electronic waste according to EU Directive 2012/19/EU and local regulations, not as unsorted municipal waste. They can also be returned to Hamilton for disposal. For safety reasons, sensors with pressurized reference systems (e.g., EasyFerm Plus, EasyFerm Bio) should be disposed of in their original polystyrene packaging to prevent injury from glass splinters.

General Information

The lifespan of a sensor is determined by its response time, zero point, and slope requirements. Measurement conditions, particularly high temperatures and aggressive solutions, can shorten this lifespan. Under favorable conditions, sensors can last 1-3 years at room temperature and approximately 1-3 months at 90°C. Minor aging also occurs during storage. Ensure no air or gas bubbles are present on the sensitive parts of the sensor, as this can lead to incorrect measurements. Each sensor is supplied with a "Declaration of Quality" detailing calibration values from the final factory test, specifications, and material information. For further details, visit "Process Analytics" at www.hamiltoncompany.com.

Use in Potentially Explosive Atmospheres

Marking:

EC-Type Examination Certificates and Certificates of Conformity can be downloaded from: www.hamiltoncompany.com. The following Memosens sensor types have ATEX approval: EasyFerm Plus *** MS ***, EasyFerm Bio *** MS ***, EasyFerm USD *** MS ***, Polilyte Plus *** MS ***, MecoTrode *** MS ***. ATEX certification for these sensors is valid only if the serial number is 4000 or higher, the sensor displays the specified ATEX marking, and an orange ring is present around the sensor connector.

Special Conditions for Safe Operation:

1. Adhere to the conditions specified in Certificates BVS 11 ATEX E 038 X and IECEx BVS 16.0079 X.
2. The operator of equipment in potentially explosive atmospheres is responsible for ensuring all system components are certified for the relevant zone and are mutually compatible.
3. Do not operate the sensor under electrostatically critical process conditions.
4. Avoid strong vapor or dust streams directly impacting the connection system.
5. If a sensor is temporarily powered by a non-intrinsically safe circuit, its ATEX / IECEx certification becomes void.
6. Before mounting or demounting the housing or sensor, ensure no explosive atmosphere is present in the reactor.
7. O-rings that prevent the escape of potentially explosive material from the reactor must be replaced each time the sensor is removed.

Thermal Specifications

The following ambient temperature ranges must be observed:

Electrical Specifications

Sensors can be connected to the H220X transmitter (Ref 242081-**) (TÜV 16 ATEX 7938 X) using measuring cables Ref 355350, 355351, or 355352 (BVS 17 ATEX E 108 X and IECEx BVS 17.0090 X). The following transmitters can also be connected to these cables: Knick PROTOS Module Type MS 3400X-16* (KEMA 03ATEX2530) and Knick STRATOS PRO Transmitter Type A20.X-.- and A21.X-.- (KEMA 08ATEX0100). Users are responsible for verifying the continued validity of the ATEX certifications for these instruments.

Connection to an intrinsically safe output circuit (Ex ia IIC) is possible with the following maximum values:

Intrinsically Safe Output Circuit (Ex ia IIC) Limits:

The maximum internal capacitance (Ci) and inductance (Li) of the intrinsically safe output circuit must not exceed:

Alternative (Trapezoidal Output Characteristic) Limits:

The maximum internal capacitance (Ci) and inductance (Li) of the intrinsically safe output circuit must not exceed: