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Hydro-Thermal’s EZ® Heater Direct Steam Injection (DSI) is the Right Pick in Jacketed Reactors and Kettles in Batch Cooking Applications.


Both Jacketed Reactors and Kettles are used for batch cooking. They are designed to control their cooking temperature using a heating/cooling ‘jacket’ around the container through which a heating or cooling fluid is circulated.

The Hydro-Thermal EZ Heater® significantly improves your batch processing with precise heating by utilizing directly-injected steam from your boiler into your water stream. This process helps create instantaneous hot water at a precise temperature for batch processing, eliminating hot spots and burn-on for better quality control. This makes Hydro-Thermal’s patented DSI technology the obvious pick when using jacketed reactors or kettles.


Benefits of the EZ Heater in Batch Cooking

The initial temperature rise in batch cooking can be as fast as the available heat transfer surface, product heat sensitivity, and water circulation rate will allow. The EZ Heater can reduce the thermal shock on glass-lined reactors by tempering the cold water at the beginning of the cooling cycle. An excessive temperature difference between the jacket water and the glass lining can cause the lining to crack and necessitate expensive repairs.

Some reactions may change from heating to cooling and back to heating several times. The EZ Heater can maintain the recycled water temperature within close limits because it is an integral part of the control system. It modulates the steam flow while it is heating the water. The faster speed of response with the Heater’s instantaneous heating results in the jacket water temperature following the setpoint as rapidly as changes are called for by a product temperature controller. Steam flow is controlled from 100% flow for maximum “come up” down to “no flow” during cooling periods. The precise temperature control obtained has enabled users to operate at optimum temperature conditions to get the batch’s most significant yield.         

Types of Jacket Reactors and Kettles


Heating Only - Vented Vessel


Figures 1For simple processes where only heating is required, the EZ Heater would be piped, as shown in Figure 1. The operator raises the Temperature Controller “setpoint” to start heating. An electrical signal from the Controller will keep the Steam Solenoid Valve open until the hatch reaches the “set point” temperature. After that, the batch may be held at this temperature, or the batch might be quickly cooled down. In this case, the Temperature Controller could have additional contacts to control the cooling period. Water is generally recirculated on large production vessels to conserve energy, but on smaller pilot plant reactors, single-pass heating is common.


Endothermic and Exothermic Reactions 




Figures 2For processes that start with heating and then become exothermic (requiring cooling) the cascade control system shown in Figure 2 is required. The master Controller measures the batch temperature and resets the jacket water Temperature Controller as the reaction changes. The automatic  EZ Heater, receiving its output from the jacket water Temperature Controller, can terminate heating before the cooling water flows through it into the vessel jacket. When the reaction slows down, the EZ Heater can quickly start heating again. The Pressure Control will modulate the overflow valve as required to maintain the jacket loop pressure.


Real-World EZ Heater Jacketed Reactors and Kettles Installations

A food processing plant needed to supply hot water at consistent temperatures during variable flow rates at four jacketed vessels in one of their cooking processes. They used another direct steam injection (DSI) Heater, which tended to foul and scale due to hard water deposits and required constant maintenance. Repair costs were on the rise, and temperature control was inadequate, causing cooking to be below standards. The plant needed to maintain accurate water temperature for batch cooking, reduce maintenance time and costs, and reduce cycle times.


Flow Rate: 400 gpm [109 m³/hr]

Inlet Temperature: 60-150°F [16-66°C]

Outlet Temperature: 205°F [96°C]

Target Mix Temperature: 200°F [93°C]

Water Pressure: 50 psig [3.5 barg]


Hydro-Thermal installed an EZ Heater® (model H2040) as part of a plug and plumb EZ Skid™ system. This size direct steam injection Heater is perfect for low flow rates and always supplies the right amount of hot water at the correct temperatures, even at varying flow rates. Now, batch cooking is consistent, and the product is up to standards. Additionally, the plant is experiencing: 20% increase in uptime due to reliability, a significant decrease in repair costs, enhanced steam and liquid turndown capabilities, and eliminated scaling and fouling.


Hydro-Thermal understands the importance of a consistent product after every batch. The EZ Heater can heat various products when using a jacketed reactor or kettle for batch cooking and significantly improves your batch processing with precise heating, elimination of hot spots, and burn-on. The result is great tasting product, consistent batches, and ultimately cost savings.

Click here to learn more about our application experience in the food and beverage industry.

Contact us at 800-952-0121 or This email address is being protected from spambots. You need JavaScript enabled to view it. today to get a free evaluation from our application experts. We can provide tips on how to optimize a heating system.



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Hydro-Thermal is the global leader in the development and manufacturing of Hydroheaters. Through our vast global channel partners, we support hydro heating in six continents and all industrialized areas. We create heating systems for a variety of industries including: pulp, paper, chemical, ethanol, food & beverage, metal, & more!

Hydro-Thermal Corporate 

400 Pilot Court
Waukesha, WI 53188 USA
Phone: (262) 548-8900
Fax: (262) 548- 8908