Hot Water Supply Systems
In the Food industry, blanching of vegetables and potatoes is a common practice. Enzymes in vegetables are inactivated by the blanching process. Blanching is the exposure of the vegetables to boiling water or steam for a brief period of time. The vegetable must then be rapidly cooled in ice water to prevent it from cooking. There are a number of applications where containers need to be cleaned and pauperised prior to being filled in the packaging process. Processes such as fruit and vegetable juice processors, potato processors, vegetable and fruit canning and so forth are all processes that require hot water supply for cleaning and washing of packages and containers prior to filling.
Blanching processes will operate at temperatures of 190-205°F (43-96°C). Water is delivered to the blancher which in turn needs to be heated prior to processing the vegetables or potatoes in the blancher. Proper temperature control ensures processing optimisation. A low pressure drop across the water heater allows for more efficient operation of the pumps and better control for the spray nozzles. There are a number of challenges associated with conventional water heating methods:
- Heat exchangers require floor space for installation space and room to remove tubes for cleaning. Other issues are lag response time, mineral and scale build-up and high pressure drop
- Traditional mechanical spargers are prone to plugging and fouling
- Conventional steam injection heaters with external stream control via a steam PRV are prone to process upsets such as hammer and vibration
| Eliminate Steam Hammer | |
PSX Heater Solution – Inline Heating
ProSonix’s unique method of steam injection utilises an integral pneumatic actuator and a variable opening steam diffuser to deliver high velocity steam injection heating. We do not throttle or regulate steam pressure. This design offers a precise method of steam control through a choked flow delivery of the steam. Choked flow is the phenomenon of accelerating a vapor to maximum velocity by creating a pressure differential through an engineered nozzle. By establishing choked flow, the steam mass flow can be metered to precisely control the heating of the liquid. This produces predictable results based on position of the stem plug. Through a variable-area steam diffuser, steam flow is metered at the point where steam and liquid first contact and mix. This method eliminates the need for an external steam control valve or downstream mechanical mixing devices. High velocity steam flow optimises the steam mixing and condensation with the liquid and eliminates problems with vibration/steam hammer.
Key Direct Steam Injection Benefits
- Precise temperature control +/- 1 °F (-17°C) assures optimal processing conditions
- Self cleaning design eliminates costly maintenance issues from scale and mineral build-up
- Energy savings as the low pressure drop (typically 1-2 psig) reduces energy pump demand
- High turndown of both steam and water flowrate allow for flexible operating conditions
- Ease of installation as the PSX heater can be installed on the pasteuriser or in the water piping above
