Endress+Hauser CPA875 Cleanfit Retractable Assembly

CPA875 Cleanfit retractable assembly for hygienic and sterile processes

The Endress+Hauser CPA875 is a retractable process assembly from the Cleanfit family. It holds a standard 12 mm sensor, such as a pH, ORP or oxygen sensor, and lets that sensor be pulled back into a sealed service chamber, rinsed, calibrated or replaced while the tank or pipe stays in operation. It is designed for sterile and hygienic duty in food and beverage, biotechnology, life sciences and special chemicals. Seven Star LLC, an independent supplier in Muscat, supplies the CPA875 and the sensors and controllers that go with it in Oman and the GCC.

The CPA875 is a modular product, and the order code is built step by step: hazardous or non-hazardous area, drive type and limit switches, service chamber, seal material, wetted surface finish, process connection, service chamber connections and cleaning position. The part number alone therefore stands for a family of configured assemblies, and the details below show what each choice means.

CPA875 technical specifications

How the CPA875 retracts a sensor without stopping the process

The sensor sits in a guide tube that can move between two end positions: the measuring position, where the tip is in the medium, and the service position, where the tip is inside a rinse chamber that is sealed from the process. In the service position the chamber can be flushed with water, cleaning agent or steam, and the sensor can be calibrated or exchanged. Special aseptic seals with no hidden crevices are used to meet the same hygiene level as the pipe connections they replace, and the chamber drains fully when the assembly is mounted within 15 degrees of horizontal.

Safety features include a locking mechanism that allows travel even without a sensor installed, limit-position locking that holds the last position if compressed air is lost, and unlocking buttons on manual drives. The protective cap covers the sensor and makes it impossible to remove the sensor while the assembly is in the measuring position. Limit positions can be reported by inductive sensors, which for pneumatic versions detect both the measuring and service positions.

CPA875 process connections and chamber options

Rinse chamber volumes range from about 10 to 21 cm³ for a single short-stroke chamber, 21 to 43 cm³ for a single long-stroke chamber, and a total of roughly 57 to 96 cm³ for the double chamber, which has a separate front chamber for an extra cleaning step.

Where the CPA875 sits in a measuring system

A typical CPA875 point has the assembly in the process, a pH or oxygen sensor with a Memosens cable (CYK10), a Liquiline transmitter such as the CM44x family, and an Air-Trol CYC10 control unit for automatic pneumatic movement. Within the Liquiline range you may also use the CM448 or CM442R as the transmitter. The datasheet lists a weld-in adapter G1¼ as accessory, straight or angled, with a safety nozzle in 316L.

The fixed-mount sibling is the Unifit CPA842, which keeps the sensor permanently in the process and suits applications where the process can be stopped for sensor changes. Choose the CPA875 when a stoppage is expensive or sterile conditions must be kept during service.

Selection checklist for a CPA875

• Manual or pneumatic: manual up to 8 bar, pneumatic up to 16 bar, with a control unit for automated cycles.
• Stroke and chamber: 36 mm for flow housings, 78 mm for vessels, and single or double chamber for the cleaning sequence.
• Sensor length: 225 mm or 360 mm and electrode type (gel, ISFET, KCl); the free path above the drive needed for a sensor change is 440 mm for 225 mm sensors and 610 mm for 360 mm sensors.
• Seal material: EPDM, FKM or FFKM according to media, temperature and steam.
• Surface and certificates: Ra 0.76 or 0.38 µm, and optional EHEDG, 3-A, ASME BPE, FDA 21 CFR or 3.1 documentation by order code.
• Process connection: choose from the code list above and check the immersion depth for the tank or pipe.
• Limit switches: inductive NAMUR switches for interlocking.

Installing and commissioning the CPA875

Mount the assembly at no more than 15 degrees to the horizontal so that rinse media drains fully, and leave the mounting height needed to withdraw the sensor, which starts at 425 mm above the drive for the short version. Use a hook wrench on NA threaded connections, never a pipe wrench. Fit the rinse lines to the chosen connection, connect compressed air for the pneumatic drive, and wire the inductive limit switches to the control system.

During commissioning, cycle the assembly between both positions with no sensor first, then with the sensor, and test the locking and the limit signals. Rinse the chamber in the service position, then calibrate. The datasheet warns that seal life shortens with constant high temperature or repeated steam-in-place, so schedule seal inspection accordingly.

Maintenance and seals for the CPA875

Replace the process seal, rinse chamber seals and drive seal on a schedule set by temperature, cleaning chemicals and steam cycles. Keep a spare seal set in the material you ordered. Check that the unlocking buttons and limit switches work and that no residue builds up in the rinse chamber. Because the assembly is classified outside the scope of the ATEX directive, use in a hazardous area depends on safe-use conditions and the version ordered; ask for the documentation.

CPA875 applications in Oman and the GCC

In Oman and the GCC the CPA875 is relevant for dairy and beverage plants, pharmaceutical and biotech facilities, bottling and food processing, and specialty chemical blending where a sensor must be removed for calibration without opening the line. The high ambient temperature calls for pneumatic supply tubing that is protected from sun and heat, and hygienic washdown water quality should be considered when choosing seal material.

Information to send with a CPA875 request

• Order code, or drive type, chamber type and stroke
• Sensor model and length
• Seal material and surface finish
• Process connection and pipe or tank size
• Process temperature, pressure and cleaning or steam conditions
• Certificates needed (3-A, EHEDG, FDA, 3.1)
• Control unit and limit switch requirements
• Quantity and delivery location in Oman or the GCC

Documents and quotation

The manufacturer technical information for the CPA875 is attached on this page and lists dimensions, ratings, materials and the ordering steps used above.

Send the code or the application details for your CPA875 and Seven Star LLC will confirm availability and quote.