Understanding Broadley-James’ pH Housings

Longer housing length

You may have questions about the Broadley-James pH Housings range, so here we have compiled some of our most frequently asked questions to help assist you.

How do I match electrodes to housings?

Our pH electrode Housings and FermProbe® pH electrodes are offered in a variety of lengths. This enables operators to select the optimum insertion length for the application at hand. The housing ordering information box lists the suitable electrode models and lengths for each particular housing style.

You can also match an electrode to suitable housings using its letter classification. Any Class “A” pH electrode will fit any Class “A” housing listed on our website. Similarly, any Class “B” electrode will fit any Class “B” housing. By matching the classifications, the electrode and housing will match.

How to match electrodes to housings

You can read further information on this topic, here.

How do I choose a housing style for my pH Electrode?

The electrode housing is designed to hold and protect the PH electrode while inserting it into the bioprocess vessel. There are various types of side entry ports and different groups of housings to fit each port type. The size and make of the port must first be identified in order to narrow the selection process.

The two most common types of entry ports found on pilot and production scale vessels are as follows:

Standard 25mm side port

STANDARD 25 mm SIDE PORT

Found on nearly all vessels other than those manufactured by B. Braun Biotech. The port bore is 25 mm in depth and the housing o-ring seals to the inside of the port.

The housing is then secured to the port by a threaded retainer ring. The port is installed at a 15° angle for better electrode performance.

 

b.braun biotech 25mm safety side port

B. BRAUN BIOTECH 25 mm SAFETY SIDE PORT

Found exclusively on vessels manufactured by B. Braun Biotech. This 25mm safety side port is longer than the standard port and needs a special housing to fit correctly.

(Note: The port opening on newer tanks is 30 mm i.d. and the port narrows down to 25 mm in depth at the critical point where the housing o-ring seals to the inside wall of the port.) Again, the port is installed at a 15° angle for better electrode performance.

You can read further information on this topic and find information about other types of port including sanitary installations, here.

Do I want a guarded or unguarded housing?

The electrode/housing assembly can accidentally “bump” into the 25 mm port when being installed. If the pH sensing glass bulb of the electrode is not protected by a housing bulb guard, the electrode can easily be shattered. A guarded housing design is often the engineer’s first choice when choosing an electrode housing.

However, sometimes the media is so viscous that it will clog the housing guard and effectively smother the pH sensing glass bulb. In this case, an unguarded housing must be used to ensure that the pH sensing glass bulb is always in contact with fresh media.

You can read further information on this topic, here.

When do I choose a longer housing length?

Sometimes the tank wall can become coated with a thick layer of viscous material that does not mix well with the rest of the media. If the pH sensing bulb of the electrode is located just a couple of inches inside the tank wall, the bulb might be smothered by this viscous layer. Subsequent pH readings may not be representative of the bulk of the media circulating in the rest of the tank. In the illustration below, the pH electrode’s bulb is trapped in this slow-moving viscous layer near the tank wall. The electrode is only measuring the pH of this layer.

Short housing length

The solution to this problem described above is to choose an electrode and matching housing that extends further into the tank. This will position the pH sensing bulb away from the tank wall and place it closer to the circulating media further inside the tank. The subsequent pH measurements will be much more representative of the circulating media. In the illustration below, the electrode and housing protrude past the viscous zone and into the area of well stirred and circulated media within the production tank.

Longer housing length

You can read further information on this topic, here.


Our Range of pH Housings

Housings for Standard 25 mm Side Ports

The 320 and 330 style electrode housings are designed to be used with the Model F-615 style FermProbe® pH electrode. These housings fit nearly all standard 25 mm side ports found in production and pilot plant vessels and are available in a variety of different lengths to suit your application.

This design requires that the pH electrode be secured to the housing by a free-spinning threaded retainer nut. This allows the electrode to be installed into or removed from the housing without twisting or disconnecting the electrode cable. This feature is very helpful when calibrating the pH electrode tank side in a production environment.

Housings for Standard 25 mm Side Ports

Housings for B. Braun Biotech 25 mm Safety Side Ports

There are two FermProbe® electrode housing designs, standard and metric, for B. Braun Biotech 25 mm side ports. These housings incorporate the latest B. Braun Biotech design requirements and are compatible with both the new 25 mm safety ports and the older 25 mm port designs. When these housings are used with the new B. Braun Biotech safety port, the port will release internal steam pressure in the vessel before the housing is completely disengaged from the port.

The standard FermProbe pH electrode (F-600, F-607 and F-615) is secured to the models 326 and 336 style housings by a free-spinning threaded retainer nut. This allows the electrode to be installed and removed from the housing without twisting or disconnecting the electrode cable. This feature is very helpful when calibrating the pH electrode tank side in a production environment.

The metric FermProbe pH electrode (D-545, D-540, F-635, F-695, F-835, F-895, F-235 and F-285) threads directly into the Models 346 and 356 style housings, eliminating the need for the threaded retainer nut. In order to prevent twisting the cable, the metric FermProbes have a detachable cable. Guarded and unguarded versions are available. Using a guarded housing is highly recommended for pH electrodes to provide maximum protection against damage to the sensing bulb. However, highly viscous media is prone to clog the guard.

Housings for B. Braun Biotech

Housings with Sanitary Flanges

Commonly used in both the food and pharmaceutical industries, the 350 series and 360 series housings are suitable for sanitary pipe systems with CIP requirements. These housings are most often found in downstream processes such as purification.

These housings are secured into a sanitary pipe tee with a standard flange clamp sealed with a flange gasket. The pH electrode is then inserted into the housing for on-line measurements.

When using a standard sanitary tee, the sensor will be positioned such that the tip of the sensor is in the middle of the process flow. T-Pull® FermProbes® are compatible with these housings. These housings are also compatible with Novaseptic side ports.

Housings with Sanitary Flanges

Metric Housings for Standard 25 mm Side Ports

These housings are designed to be used with models F-635 and F-695 Metric FermProbe® electrodes and models D140 and D145 12 mm OxyProbe® sensors. They are also compatible with any sensor that has Pg13.5 threads. These housings fit nearly all standard 25 mm ports found on production and pilot plant vessels. Different housing lengths are available to accommodate various application or vessel requirements.

The pH electrode or D.O. sensor threads directly into this metric housing, eliminating the need for a threaded retainer nut. In order to prevent twisting the cable, the metric FermProbes have a detachable cable. Guarded and unguarded versions are also available. Using a guarded housing is highly recommended for pH electrodes to provide maximum protection against damage to the sensing bulb. However, highly viscous media is prone to clog the guard.

Metric Housings for Standard 25 mm Side Ports


If you have any further queries, please feel free to take a look at our FAQ page. It offers information on a wide variety of topics such as probes, transmitters and measurements. If you cannot find the answer to a specific question, please feel free to contact us and we will assist in any way we can.