Advantages and disadvantages of fixed sprays devices, single-axis rotary sprays, and multi-axis rotary sprays
For cleaning vessels, the spray device, location(s) and flow rate/ pressure are critical criteria for thorough cleaning of the process system. The proper spray device(s) must first be selected and then the CIP supply pump must be determined based on the required flow and pressure.
There are many factors to consider when choosing a spray device:
- Product residues – liquid, viscous, solid, sticky, dried, granules, dough, etc.
- Type of equipment – silos, tanks, ducts, mixers, dryers, evaporators, fillers, etc.
- Vessel configuration/ size – vertical, horizontal round, rectangular, dimensions.
- Is there a mixer or baffle?
- Does the spray device remain in the product?
- Can the product close the holes or stop the rotary machine from spinning?
Spray devices may include; Stationary sprays are uniaxial rotating sprays or multi-axis orbital sprays.
Spray devices in sanitary applications must also be completely aseptic Hygiene Standard A-3 for spray equipment defines criteria for hygienic sprays, including materials, surface coatings/finish, corner radii, cleaning capability, and others that are critical to food processing equipment.
Fixed spray devices
Fixed sprays are the most common type of sprays made with the advent of CIP cleaning. They are for light residues such as fluid milk, whey, beverages and other easily removable soils; they are proper. These devices clean the residues by cascading with chemical decomposition.
The advantages of fixed spray devices include cheapness and no use of moving parts for wear. They can be sprayed directly to the desired location and their spray pattern can be easily programmed. These devices are also easy to inspect and maintain.
Disadvantages of fixed spray devices include their low impact on resistant residues. They may also not completely cover irregular surfaces and have limited performance in spray coating.
Single-axis rotary spray
Single-axis rotary sprays are devices that rotate due to the reaction of solutions flowing out of the orifices.
The advantage of single-axis rotary sprayers is that they are more effective than fixed sprayers for residues and also cover irregular surfaces. These devices provide complete coverage at the desired spray zone and better cleaning performance at lower flow rates than fixed sprays.
Nevertheless; These devices are easily stopped by foreign particles and their parts wear out over time.
Multi-axis rotating sprays
Multi-axis rotary sprays are devices that rotate the flow of fluid through a turbine or by an external driver. Spray nozzles spin in a circuit like a ball of yarn and can cover large areas with a device through a 360-degree circuit.
The advantages of these spray devices include their high impact for cleaning difficult residues and good spray coverage over long distances. They also operate at lower flow rates than other spray devices and have good spray coverage for irregular surfaces.
However, such devices also have a high initial cost.
Other points
Regardless of the spray device selected, the CIP supply system must have a suitable filter or purifier to prevent particles from plugging or stopping the devices from rotating.
When there is a mixer, baffle or blind areas at the upper ports, multiple sprays are needed to prevent “shadowing”. To ensure complete coverage of spray applications, a “riboflavin test” can be performed to confirm that the spray device provides complete coverage of all surfaces by direct impact, cascade flow, or secondary impact. This operation does not confirm the cleaning performance with the actual product residue, but proves that all surfaces have a CIP solution coverage.
It is recommended that users perform the test to ensure that the selected spray devices provide the required coverage and confirm the cleaning performance under actual operating conditions and CIP.
Reference:
https://www.dairyfoods.com/articles/95364-selecting-a-spray-device-for-clean-in-place-equipment
