Method and system for controlling and/or regulating the treatment of heat-sensitive liquid food products
Controlling and/or treating heat-sensitive liquid food products ensures improved control of a filling level in an infuser container. Therefore, a constant dwell time of the product to be heated is reached in the event of product-fouling in the centrifugal pump. The pump is designed such that one part of a volume flow of the product, transported by an impeller wheel, regularly rinses the impeller wheel and the areas of a pump chamber that are directly adjacent to the impeller wheel. A reduction in the volume flow of the centrifugal pump is then counteracted by increasing the initial rotational speed if the reduction is simultaneously associated with a drop in temperature of the product. The increase of the initial rotational speed is carried according to the drop in temperature of the product and/or an increase in the temperature of the steam to constantly maintain at least the temperature of the product.
1. A method for controlling and/or regulating treatment of a heat-sensitive liquid food product, comprising:
heating the liquid food product directly with steam to establish a germ-free state in an infuser container;
removing water from the liquid food product by flash evaporation at a low pressure in an amount that corresponds to that of the previously supplied steam;
delivering the liquid food product by means of a centrifugal pump between heating and flash evaporation; and
cooling the liquid food product in at least one section of this flow path by each associated wall bordering this flow path starting upon entry into a base region of the infuser container and at most until entering the centrifugal pump, wherein:
the centrifugal pump has an inlet, an outlet, and a pump housing that is formed by at least a housing cover and a housing rear wall, and in which pump housing a pump chamber is formed which is in fluidic connection with the inlet and the outlet,
the centrifugal pump has an impeller wheel rotatably accommodated in the pump chamber, and the impeller wheel is designed open toward the housing cover and closed to the housing rear wall by a rear side of the impeller wheel,
the centrifugal pump has a front impeller wheel gap provided between the housing cover and the impeller wheel, and a rear impeller wheel gap provided between the housing rear wall and the impeller wheel,
the front impeller wheel gap is increased up to several times in comparison to a minimum front impeller wheel gap that ensures mechanical functioning of the centrifugal pump by reducing a width of the impeller wheel,
the front impeller wheel gap undergoes a maximum increase at an outer diameter of the impeller wheel that decreases to the minimum front impeller wheel gap into a region of an entrance into blade channels of the impeller wheel, and
a reduction of the width of the impeller wheel at the outer diameter of the impeller wheel is 40 to 50% of the width of a hydraulically optimized impeller wheel;
and the method comprising:
(a) detecting a product temperature downstream after the centrifugal pump of an infuser-heated liquid food product and regulating the product temperature by supplying steam at a steam temperature to a head region of the infuser container at a product-specific product temperature setpoint to be achieved as specified, wherein a drop in the product temperature causes a rise, and a rise in the product temperature causes a drop, in the steam temperature;
(b) operating the centrifugal pump in an initial phase of the treatment of the liquid food product at an initial rotational speed below a rated rotational speed of the centrifugal pump by a predetermined amount, wherein the initial rotational speed is dependent on at least one of the liquid food product or a design of the centrifugal pump;
(c) counteracting a reduction of the volumetric flow of the centrifugal pump by increasing the initial rotational speed when the reduction occurs at the same time as a temperature drop of the product temperature;
(d) increasing the initial rotational speed depending on at least one of the temperature drop of the product temperature or a temperature rise of the steam temperature, wherein an extent of the increase in the initial rotational speed results from a regulatory requirement to keep at least the product temperature constant; and
(e) repeating steps (c) and (d) until at least one of a specified product temperature setpoint to be achieved or the steam temperature needed to achieve the product temperature setpoint at the start of treatment, consistently occurs.
2. The method according to claim 1 , wherein the increase in the initial rotational speed occurs steadily.
3. The method according to claim 2 , wherein a gradient of the increase in the initial rotational speed results from regulatory requirements, and is set depending on at least one of the drop in the product temperature, the rise in the product temperature, or on product-specific requirements.
4. The method according to claim 3 , wherein at least one of the initial rotational speed or the product temperature setpoint is set depending on default parameters that are characteristic of the liquid food product, wherein the default parameters are selected from a group consisting of physical variables of the liquid food product, density of the liquid food product, viscosity of the liquid food product, thermal conductivity of the liquid food product, composition of the liquid food product, fat content of the liquid food product, and protein content of the liquid food product.
5. The method according to claim 3 , wherein at least one of the initial rotational speed or the product temperature setpoint is adjusted depending on physical boundary conditions to which the method is subjected, wherein the physical boundary conditions are selected from a group consisting of process-related default parameters of the method, pressure of the method, and temperature of the method.
6. The method according to claim 3 , wherein at least one of the initial rotational speed, the product temperature setpoint, or either of a rotational speed differential and a gradient of the increase in the initial rotational speed is adjusted by means of a calibration function tested and saved before or while starting the method.
7. The method according to claim 3 , further comprising:
supplying the liquid food product annularly, and impinging the liquid food product from the inside by internal steam and from the outside by external steam, and
the supply of the external steam is adjusted depending on a required supply pressure for the internal steam in the head region of the infuser container, and by differential pressure regulation.
8. The method according to claim 2 , wherein at least one of the initial rotational speed, the product temperature setpoint, or either of a rotational speed differential and a gradient of the increase in the initial rotational speed is adjusted by means of a calibration function tested and saved before or while starting the method.
9. The method according to claim 2 ,
wherein at least one of the initial rotational speed or the product temperature setpoint is set depending on default parameters that are characteristic of the liquid food product, wherein the default parameters are selected from a group consisting of physical variables of the liquid food product, density of the liquid food product, viscosity of the liquid food product, thermal conductivity of the liquid food product, composition of the liquid food product, fat content of the liquid food product, and protein content of the liquid food product.
10. The method according to claim 2 , wherein at least one of the initial rotational speed or the product temperature setpoint is adjusted depending on physical boundary conditions to which the method is subjected, wherein the physical boundary conditions are selected from a group consisting of process-related default parameters of the method, pressure of the method, and temperature of the method.
11. The method according to claim 2 , further comprising:
supplying the liquid food product annularly, and impinging the liquid food product from the inside by internal steam and from the outside by external steam, and
the supply of the external steam is adjusted depending on a required supply pressure for the internal steam in the head region of the infuser container, and by differential pressure regulation.
12. The method according to claim 1 , wherein the increase in the initial rotational speed occurs in at least one discrete step with a rotational speed differential that results from regulatory requirements.
13. The method according to claim 12 , wherein the rotational speed differential is set depending on at least one of the drop in the product temperature, the rise in the product temperature, or product-specific requirements.
14. The method according to claim 12 , wherein at least one of the initial rotational speed or the product temperature setpoint is set depending on default parameters that are characteristic of the liquid food product, wherein the default parameters are selected from a group consisting of physical variables of the liquid food product, density of the liquid food product, viscosity of the liquid food product, thermal conductivity of the liquid food product, composition of the liquid food product, fat content of the liquid food product, and protein content of the liquid food product.
15. The method according to claim 12 , wherein at least one of the initial rotational speed or the product temperature setpoint is adjusted depending on physical boundary conditions to which the method is subjected, wherein the physical boundary conditions are selected from a group consisting of process-related default parameters of the method, pressure of the method, and temperature of the method.
16. The method according to claim 12 , wherein at least one of the initial rotational speed, the product temperature setpoint, or either of a rotational speed differential and a gradient of the increase in the initial rotational speed is adjusted by means of a calibration function tested and saved before or while starting the method.
17. The method according to claim 12 , further comprising:
supplying the liquid food product annularly, and impinging the liquid food product from the inside by internal steam and from the outside by external steam, and
the supply of the external steam is adjusted depending on a required supply pressure for the internal steam in the head region of the infuser container, and by differential pressure regulation.
18. The method according to claim 1 , wherein at least one of the initial rotational speed or the product temperature setpoint is set depending on default parameters that are characteristic of the liquid food product, wherein the default parameters are selected from a group consisting of physical variables of the liquid food product, density of the liquid food product, viscosity of the liquid food product, thermal conductivity of the liquid food product, composition of the liquid food product, fat content of the liquid food product, and protein content of the liquid food product.
19. The method according to claim 1 , wherein at least one of the initial rotational speed or the product temperature setpoint is adjusted depending on physical boundary conditions to which the method is subjected, wherein the physical boundary conditions are selected from a group consisting of process-related default parameters of the method, pressure of the method, and temperature of the method.
20. The method according to claim 1 , further comprising:
supplying the liquid food product annularly, and impinging the liquid food product from the inside by internal steam and from the outside by external steam, and
the supply of the external steam is adjusted depending on a required supply pressure for the internal steam in the head region of the infuser container, and by differential pressure regulation.