Coventional Sanitary Sensors create stagnant fluid zones, or "dead-legs" where they connect into the process pipework. These create problems with gas entrapment during the filling phase of the process, and hold-up of product during and after draining. This is particularly problematic for higher viscosity products that do not easily self-drain under gravity and where CIP and SIP procedures cannot remove all the retained product, requiring removal of the sensors from the process pipe for manual cleaning and inspection.

Keyhole™ Sensors eliminate stagnant fluid zones and crevices by forming a completely flush hygienic seal with the wall of the process pipe. No uncleaned voids or crevices to contaminate product flow. No product wastage in hold-up pockets. Full CIP/SIP performance with no need for removal for manual cleaning.

Any Orientation
The lack of any process dead-leg also allows Keyhole sensors to be installed in any orientation: pointing up, down, 45^o, vertical or horizontal - and in almost any location according to the space available without impacting their hygienic performance.

High Pressure Operation
Because of the unique way that the Keyhole seal works, the sensors are also excellent for higher pressure environments. All models operate leak-free up to 750psig (50Bar). The Small Bore Sensors and Fittings operate as high as 3,000psig (200Bar).

Edge Measurement
The Low Flow Obstruction tip profile enables the Keyhole™ sensor to measure the product temperature near the pipe wall. The thermal isolation of the Keyhole probe from the pipe wall allows a more accurate measurement of the product than conventional sensors that mount on the exterior surface of the pipe wall, or are forced to "reach across" to the far side of the pipe wall in order to acheive their required immersion depth.

This capability is particularly important for products with laminar flow patterns, where there can be significant temperature differences between the edge and the center of the flow. Modern thermal processing technologies can also result in a cold zone being at the edge of the flow rather than the center, requiring the critical control point measurement to be near the pipe wall.

Multi-Point Measurement
Advanced thermal processing techniques such as microwave, RF and ohmic heating can produce very different product thermal profiles to traditional heat exchangers. Determining this radial temperature profile is necessary for proper process operation and validation.

Thermal profiles can be measured by Keyhole Multi-point probes. These are constructed from ultra-thin 0.060" (1.5mm) diameter stainless steel probe tips equipped with multiple thermocouples to simultaneously measure at multiple points across the product flow. Use of an ultra-thin walled probe minimizes heat conduction between adjacent measurement points and increases the accuracy of each reading. The probe tip can be curved in the direction of the flow to reduce the risk of fouling.

Single-point probes using miniature thin-film PT100 elements are also available in this tip style.

Measurement Sensitivity
Keyhole™ Sanitary Sensors have superior temperature sensitivity and response times thanks to the small thermal mass of the wetted tip that is isolated from the rest of the sensor body, the sensor fixture, and other process equipment. Sensors with response times as quick as 5 seconds for a 63% step change are available.

Because of their unique process insertion mechanism that does away with the traditional tee or elbow, Keyhole™ sensors are able to be placed in locations conventional RTDs or thermocouples cannot. Difficult Locations such as long straight runs, vertical runs, bends, a vessel wall, etc are all possible without compromising hygienic performance.

Any Orientation
The lack of any process dead-leg also allows Keyhole sensors to be installed in any orientation - pointing up, down, 45^o, vertical or horizontal - and in almost any location according to the space available without impacting their hygienic performance.

High Pressure Operation
Because of the unique way that the Keyhole seal works, the sensors are also excellent for higher pressure environments. All models operate leak-free up to 750psig (50Bar). The Small Bore Sensors and Fittings operate as high as 3,000psig (200Bar).

Small Bore Installation
Because traditional RTDs require a minimum insertion depth to maintain their accuracy, their size becomes a greater proportion of the pipe size the smaller the pipe becomes. Using the Low Flow Obstruction tip design, Keyhole sensors can be made to fit pipe sizes down to 0.5" (13mm) ID with minimal obstruction.

Tank or Vessel Installation
The Low Flow Obstruction tip profile style of probe can also be used for measuring product temperature adjacent to the internal wall of a batch processing tank or vessel. The very short immersion depth required for the probe avoids interference with any rotating agitator blades, while remaining thermally isolated from the temperature of any heating jacket on the vessel.