Method and system to decouple steam pressure from temperature to control shear imparted on product flow
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Solution Overview
Problem
Current direct steam injection technologies face challenges in controlling temperature and shear in food processing, with pressure changes being non-instantaneous, leading to temperature fluctuations, and low pressure differentials limiting high shear conditions, while orifice size modulation results in significant shear damage during temperature changes.
Innovation Solution
A system that decouples steam pressure from temperature using a steam modulator and PID control to vary steam orifice sizes, allowing precise control of shear and temperature through a plurality of steam injection heaters, enabling repeatable high shear and low shear conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If steam pressure is modulated to control temperature, then temperature control is achieved, but temperature fluctuations occur due to non-instantaneous pressure changes
Solution Approach 1:
The patent replaces mechanical pressure modulation with electronic PID control of steam injection rate. The system uses a temperature sensor, controller, and variable frequency drive to control the steam injection pump, substituting mechanical pressure control with an electronic control system that responds instantaneously to temperature changes.
Solution Approach 2:
The patent implements feedback control by continuously monitoring product temperature with a temperature sensor and using this information in a PID controller to adjust steam injection rate. This closed-loop feedback system eliminates temperature fluctuations by immediately responding to any deviation from the setpoint.
2Force
If steam pressure is increased to achieve high velocity for high shear conditions, then shear mixing capability is improved, but temperature control precision deteriorates
Solution Approach 1:
The patent makes the steam injection system dynamic by using a variable frequency drive to continuously adjust the steam injection pump speed based on real-time temperature feedback. This dynamic control allows the system to maintain precise temperature control while adjusting shear conditions as needed, rather than being locked into fixed pressure/velocity conditions.
Solution Approach 2:
The patent changes the controlled parameter from steam pressure to steam injection rate. By controlling the amount of steam injected per unit time rather than the steam pressure, the system can independently optimize both shear conditions and temperature control precision without the trade-off inherent in pressure-based systems.
3Temperature
If orifice size is increased to inject more steam for greater temperature change, then temperature control range is improved, but shear damage to product increases
Solution Approach 1:
The patent segments the steam injection process into controllable pulses or continuous low-rate injection through pump speed modulation, replacing a single large orifice with a controlled delivery system. This allows the same temperature change to be achieved through extended time at low shear rather than immediate high shear injection.
Solution Approach 2:
The patent dynamically adjusts the steam injection rate to match the exact heating requirement, using pump speed control to deliver precisely the amount of steam needed. This eliminates the need for large orifices that cause excessive shear, as the system can achieve the same temperature change through controlled, lower-velocity injection over appropriate time periods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves precise temperature control with minimal shear variation, allowing for consistent product quality and high shear conditions necessary for mixing and cooking, while preventing product damage and maintaining aseptic conditions.
Implementation Method 1
The present disclosure provides a method and system to decouple steam pressure from temperature of food using direct steam injection
Implementation Method 2
the velocity of the steam impacting the process fluid... For any given pressure, there is a set velocity of steam penetration
Data Source
AI summary
A cooking system for cooking a product flow utilizing steam. A supply of steam is provided at a supply pressure that is regulated by a control unit to a regulated pressure. The supply of steam is provided to a plurality of steam injection cookers which are positioned within a product supply pipeline that receives a product flow. The product flow is cooked as the product flow passes through the product supply pipeline and the plurality of cookers. Each of the steam injection cookers includes a steam modulator that controls the amount of steam injected. By regulating the steam pressure and the steam modulator, the control unit can modify the amount of shear created within the product flow and control the temperature of the fluid. The cooking system further includes a clean-in-place system that can inject a cleaning solution into the steam supply pipeline and the plurality of steam injection cookers.