SPRAY NOZZLE FOR SPRAYING AN ARTICLE TO BE DRIED, SPRAY DRYER, AND METHOD FOR MONITORING AND/OR CONTROLLING AND/OR REGULATING A TEMPERATURE DURING THE SPRAYING PROCESS

Abstract

A spray nozzle is used for spraying a product to be dried, wherein the spray nozzle has a groove on an outer wall, and a measurement sensor for measuring a measured value is disposed in the groove, wherein an autarkic energy supply is associated with the measurement sensor. The autarkic energy supply, in particular by means of a piezo-element, is disposed in the groove, so that the measurement sensor can be operated without an external cable-based energy supply. In addition, a spray dryer is used for drying a product to be dried and to a method for monitoring and/or controlling and/or regulating a temperature when drying a product to be dried.

Claims

1. A spray nozzle for spraying a product to be dried, wherein the spray nozzle comprises: a groove on an outer wall, wherein a measurement sensor for measuring a measured value is disposed in the groove, and wherein an autarkic energy supply is associated with the measurement sensor and/or the autarkic energy supply is disposed in the groove, so that the measurement sensor can be operated without an external cable-based energy supply.

2. The spray nozzle according to claim 1, wherein the measurement sensor comprises: an emitter and an antenna for wireless transmission of a measurement signal.

3. The spray nozzle according to claim 2, wherein the measurement sensor and/or the antenna is embedded in the groove by a casting material.

4. The spray nozzle according to claim 2, wherein an external receiver for reading, evaluating and/or monitoring the measurement signal is assigned to the spray nozzle.

5. The spray nozzle according to claim 2, wherein the emitter has a frequency in the range of 9 kHz to 300 GHz.

6. The spray nozzle according to claim 2, wherein a piece of information for identifying the spray nozzle can be sent by the emitter.

7. The spray nozzle according to claim 1, wherein the measurement sensor is a temperature sensor and/or a pressure sensor.

8. The spray nozzle according to claim 1, wherein the spray nozzle is connected with a supply line by a detachable connection.

9. A spray dryer for drying a product to be dried, characterized by at least one spray nozzle according to claim 1, a measurement sensor for measuring a measured value disposed in the container, wherein the measurement sensor has an assigned autarkic energy supply,. and/or an autarkic energy supply so that the measurement sensor can be operated without an external cable-based energy supply, so that a drying process of the product to be dried can be captured and measured and/or monitored as of a measurement signal of the measurement sensor of the spray nozzle or in the container.

10. A method for monitoring,. and/or controlling,. and/or regulating a temperature when spraying of a product to be dried by the spray nozzle according to claim 1, the method comprising: spraying the product to be dried by the spray nozzle in a drying gas, measuring the temperature by a measurement sensor of the spray nozzle during the drying process of the product to be dried, monitoring, and/or controlling, and/or regulating the temperature during the drying process of the product to be dried.

11. The spray nozzle according to claim 1, wherein the autarkic energy supply is a piezo element.

12. The spray nozzle according to claim 5, wherein the emitter has a frequency in the range of 400 MHz to 2.5 GHz.

13. A method for monitoring, and/or controlling, and/or regulating a temperature when spraying of a product to be dried in the spray dryer according to claim 9, the method comprising: spraying a product to be dried by the spray nozzle in a drying gas, measuring the temperature by a measurement sensor of the spray nozzle during the drying process of the product to be dried, and monitoring, and/or controlling, and/or regulating the temperature during the drying process of the product to be dried.

14. The spray dryer according to claim 9, wherein the measurement sensor is disposed in a groove on an outer wall of the spray nozzle.

15. The spray dryer according to claim 9, wherein the autarkic energy supply is a piezo element.

Description

[0067] In the following, the invention will be described in more detail based on exemplary embodiments. In the drawings:

[0068] FIG. 1 shows a schematic perspective representation of a two-substance nozzle with a SAW-Sensor in an outside groove and

[0069] FIG. 2 shows a highly schematic sectional representation of a spray dryer with six two-substance nozzles.

[0070] A two-substance nozzle 101 comprises a nozzle opening 115 at its lower end. A radially circumferential groove 103 is placed in the outer casing of the two-substance nozzle 101 at a distance of 10 mm from the nozzle opening 115. A SAW-sensor 105 is disposed in the groove 103. The SAW-sensor 105 comprises a piezo-electric substrate 107, an emitter 109 and an antenna 111.

[0071] The piezoelectric substrate 107 is clamped in the groove 103 in a dimension of the groove 103 oriented in the longitudinal direction of the two-substance nozzle 101. In contrast, the width of the SAW-sensor 105 and of the piezoelectric substrate 107 in the radial direction is smaller than the dimension of the circumferential groove 103.

[0072] The SAW-sensor 105 measures 53 mm.sup.2 and weighs 2 g. The SAW-sensor 105 is embedded together with its antenna 111 in the groove 103 by means of a quartz glass 113, so that the groove 103 is completely filled with the quartz glass 113.

[0073] At its head, a spray dryer 119 comprises a hot-air supply 123, a milk supply 129, an air distributor 131 and six two-substance nozzles 101. The drying chamber 133 is disposed below the six two-substance nozzles 101 and a milk powder and air outlet is located at the bottom end of the spray dryer 119. An external receiver 117 is disposed at a 15 m distance from the spray dryer 119.

[0074] The following work steps are carried out by the spray nozzles 101 in the spray dryer 119:

[0075] Previously partly dehydrated milk is supplied by way of the milk supply 129 and hot air with a temperature of 180 C. is supplied by way of the hot-air supply 123 and the air distributor 131 to the six two-substance nozzles 101 in the spray dryer 119. The previously partly dehydrated milk is sprayed in fine droplets by means of the six two-substance nozzles 101 and dried by the hot air introduced with the current. In doing so, the sprayed droplets fall with the current through the hot air flow 121, thus forming, within one second, milk powder, which is heated to a temperature of 60 C. The dried milk power is discharged at the foot of the spray dryer 119 by way of the milk powder and air outlet 135. The milk powder is then separated from the air flow by way of a centrifugal separator not shown.

[0076] During spraying of the previously partly dehydrated milk, the SAW-sensors 105, which are respectively disposed at the six two-substance nozzles 101, measure the respective temperatures. Since the piezoelectric substrates 107 are respectively clamped between the two opposite walls of the respective groove 105 in the longitudinal direction of the two-substance nozzle 101, the piezoelectric substrates 107 respectively generate an electric voltage, which serves to continuously or discontinuously supply the respective SAW-sensors 105 with an electric voltage.

[0077] The SAW-sensors 105 send their temperature measurement signals respectively by means of their emitter 109 and their antenna 111 to the external receiver 117. In doing so, the SAW-sensors 105 emit at different frequencies in a range of frequencies of 2,400 MHZ to 2,483 MHz. Thus, the external receiver 117 can unambiguously identify the six two-substance nozzles 101 and unambiguously attribute the transmitted temperature signals to the individual two-substance nozzles 101. The external receiver 117 monitors the temperature signals of the six two-substance nozzles 101 during drying of the previously partly dehydrated milk powder.

[0078] The receiver 117 detects an increased temperature at one of the six two-substance nozzles 101 and causes a reduction of the hot-air flow through this two-substance nozzle 101 by way of a programmable logic controller. Since the subsequent measurements at this two-substance nozzle 101 continue to show an excessively high temperature, this two-substance nozzle 101 is automatically shut down, in order to prevent a possible inflammation of deposited milk powder at this two-substance nozzle 101.

[0079] Thus, a two-substance nozzle and a spray dryer are provided, which ensure a homogeneous temperature distribution in the drying chamber during spraying of previously partly dehydrated milk and thus reduce the risk of fire and explosion. At the same time, the homogeneous temperature distribution at all the two-substance nozzles allows for the production of a high-quality and uniformly dried milk powder.

LIST OF REFERENCE NUMERALS

[0080] 101 Two-substance nozzle [0081] 103 Groove [0082] 105 SAW-sensor [0083] 107 Piezoelectric substrate [0084] 109 Sender [0085] 111 Emitter [0086] 113 Quartz glass [0087] 115 Nozzle opening [0088] 117 External receiver [0089] 119 Spray dryer [0090] 121 Hot-air flow [0091] 123 Hot-air supply [0092] 129 Milk supply [0093] 131 Air distributor [0094] 133 Drying chamber [0095] 135 Milk powder and air outlet