The Armfield FT94X HTST/UHT Mini Pilot system extends the range of continuous operation scaled-down units offered by Armfield to 200 l/hr (30-100 l/hr standard format). The unit combines full flexibility – plate and tubular heat exchanger options – with comprehensive instrumentation demanded of research and development equipment. The FT94X is designed for operation as both a standalone unit and also for seamless integration into a full processing system with the capability of aseptic packaging of processed product.
The FT94X service unit contains the services, controls and instrumentation required to operate the tubular and plate heat exchangers described below. The FT94X may be specified with either or both of the heat exchangers. Switching between the two heat exchangers takes a matter of seconds.
The service unit comprises: a 20cm colour touchscreen with the required controls and displays; a variable-speed progressing cavity product feed pump with inlet level sensor and alarm to warn of low product level; a steam-heated hot water system for product preheating; automatic steam control valves for product preheating and final heating; a centrifugal CIP pump and other facilities required for CIP and SIP.
Sensors show product inlet, preheat, final heating and outlet temperatures. Product preheat and final heating temperatures are set by the operator. Inlet and outlet product pressure is also shown. There are various service sensors: pressure, level and temperature – see process flow diagram for details.
A sophisticated data-logging package enables the measured data to be recorded onto a standard Windows PC (not supplied). The software records all temperatures, product and steam pressures, feed pump speed and many other sensor values. Data from optional accessories (eg the flow meter) is also recorded. Data may be displayed in tables and graphs (both real-time and comparisons across previous runs), and may also be exported to MS Excel.
Software requirements: Win 98, ME, 2000, XP
An alternative data-logging system (FT94-46) allows the temperature information to be recorded to an external computer via an ethernet connection, without any operator intervention. This is an ideal system for quality control purposes.
The FT94-30 uses the sanitary heat exchanger employing the latest plate design for efficient heat transfer. Performance scale-up is straightforward. The standard unit is a three-stage system with preheat (hot water) final heating (steam) and cooling (water/chilled water).
The plates have a complex pressed profile to maximise turbulence and minimise dead zones. There is a relatively large gap between plates to allow handling of more viscous products. The plates are fitted with food-grade Viton paraclip gaskets for easy replacement as these are simply clipped in place rather than glued.
A number of options are available to enhance the performance of the standard plate heat exchanger. These options involve additional plate configurations which can be supplied fitted or may be easily retro-fitted by the user.
The FT94-32 homogeniser interconnecting plate enables the homogeniser to be connected downstream of the heating section. The plate is fitted into the cooling section.
The FT94-33 two-stage cooling option provides a complete additional cooling stage, which can be used in conjunction with a chilled water/glycol supply for the best possible product cooling. Output temperatures below 5°C are possible depending on the product and the flow rate. An interconnecting link is provided so that the two stages can be operated as a single stage when required.
The FT94-30 has a five-second holding tube (at 50 l/hr) as standard. Contact Armfield for longer holding times.
The FT94-20 is a standard tubular heat exchanger design using a series of concentric 316 stainless steel tubes for product preheating, final heating and cooling. In all cases the product passes down the inner tube and the heating/cooling medium passes through the annulus. Two heating tubes of 1.5m length are used to preheat the product. Four similar tubes are used for product heating and an additional four tubes are used for product colling.
Product is gently preheated using a hot-water system, which is itself heated by steam via a secondary service heat exchanger. In the main heating section the product is indirectly heated using steam itself. Product is cooled normally using water or chilled water. The cooling section can be configured to allow two stages where the first stage is water/chilled water and the second stage is water/glycol.
The FT94-21 is a set of static mixers for two tubes. These significantly improve heat transfer with more viscous products and can be used for improving both heat and cooling efficiency. Multiple sets can be used to optimise both heating and cooling performance.
The FT94-22 product divert option enables product that has not been processed to a sufficiently high temperature to be diverted to drain thus ensuring product quality and heat treatment. The divert temperature is adjustable. Diversion is achieved using a low hold-up twin diaphragm valve block operated by compressed air and PLC controlled. Diverted product is cooled in a tubular heat exchanger before being led to drain.
The FT94-20 has a one second holding tube (at 50l/hr) as standard. Contact Armfield for longer holding times.