Photoelectric Sensors in the Packaging, Food, and Beverage Industry

The PFB industry requires the highest standards of quality and productivity when it comes to both their products and their equipment. In order to keep up with the rising demands to produce high quality parts quickly, many in the industry have incorporated photoelectric sensors into their lines. With their durable designs, accurate measurements and fast data output speeds, it is easy to see why. Combine the sensors’ benefits with the clean and well-lit environment of a PFB plant, and it begins to feel like this product was made specifically for the industry. There are many variants of photoelectric sensors, but the main categories are: through beam, diffuse, and retro-reflective sensors.

Through Beam

Through beam sensors come in many different shapes and sizes but the core idea stays the same. An emitter shoots LED red, red laser, infrared, or LED infrared light across an open area toward a receiver. If the receiver detects the light, the sensor determines nothing is present. If the light is not detected, this means an object has obstructed the light.

Applications:

  • Object detection during production
  • Detecting liquid in transparent bottles
  • Detecting, counting, and packaging tablets

Diffuse Beam

Diffuse beam sensors operate a little differently in that the emitter and receiver are in the same housing, often very closely to one another. With this sensor, the light beam is emitted out, the light bounces off a surface, and the light returns to the receiver. The major takeaway with the diffuse beam sensor is that the object being detected is also being used as the reflecting surface.

Applications:

  • Label detection
  • Monitoring the diameter of film
  • Verifying stack height on pallet

Retro-Reflective Beam

Retro-reflective sensors are similar to diffuse beam sensors in that the emitter and receiver are also contained within the same housing. But this sensor requires an additional component — a reflector. This sensor doesn’t use the object itself to reflect the light but instead uses a specified reflector that polarizes the light, eliminating the potential for false positive readings. Retro-reflective sensors are a strong alternative to through beam when there isn’t room for two separate sensor heads.

Applications:

  • Transparent film detection
  • Detection of shrink-wrapped pallets
  • Detecting any reflective target

Zone Defense: How to Determine If You Need a Hygienic or Washdown Solution

It goes without saying that food safety is an extremely important aspect of the food and beverage industry. While manufacturers would naturally take precautions to ensure their food products are safe to consume, they are required to follow a set of rigid guidelines and standards to ensure the safety of the foodstuffs to prevent contamination.

CaptureTo determine which rating, standards or certifications are required for a particular food and beverage segment, you must first consider the type of food contact zone and whether it is an open or closed process.

Food Contact Zones

The food contact zone is determined by the potential contamination that can occur based on the production equipment’s exposure to food and its byproducts.

  • Food Zone: an area intended to be exposed to direct contact with food or surfaces where food or other substances may contact and then flow, drain or drain back onto food or food contact surfaces.
  • Splash Zone: an area that is routinely exposed to indirect food contact due to splashes and spills. These areas are not intended for contact with consumable food.
  • Nonfood Zone: An area that is not exposed to food or splashes but will likely be exposed to minor dirt and debris.

Open and Closed Production

In the food and beverage industry, it is also important to discuss whether the manufacturing process is open or closed. The distinction between the two plays a significant role in determining machine cleaning requirements.

  • Closed Process: A manufacturing operation in which the food product never comes in contact with the environment. All food contact zones are sealed such as the inner surfaces of tanks, pipelines, valves, pumps and sensors.
  • Open Process: A manufacturing operation in which food does have contact with the environment outside of the machine. This requires a hygienic design of the process environment, as well as the surfaces of the apparatus and components.

Required ratings, standards and certifications

Once you know the food zone and whether the production is open or closed, it becomes simple to determine which ratings, standards or certifications are required of the machinery and apparatus in the food and beverage manufacturing process.

  • Food Contact Zone — Hygienic
    • IP69K – tested to be protected from high pressure steam cleaning per DIN40050 part 9
    • FDA – made of FDA approved materials, most often 316L stainless steel
    • 3-A – certified sanitary and hygienic equipment materials and design in the US
    • EHEDG – certified sanitary and hygienic equipment materials and design in Europe
  • Food Splash Zone — Washdown
    • IP69K – tested to be protected from high pressure steam cleaning per DIN40050 part 9
    • ECOLAB – surfaces tested to be protected from cleaning and disinfecting agents
  • Nonfood Zone — Factory Automation
    • IP67 – rated for water immersion up to a meter deep for half an hour
    • IP65 – rated as dust tight and protected against water projected from a nozzle

For more information on the requirements of the food and beverage industry, visit www.balluff.com.

When to Use Hygienic Design vs. Washdown

Both washdown and hygienic design are common terms used in the food and beverage industry, and are increasingly being used in the packaging industry. These terms are used in different scenarios and easily confused with each other. What exactly are the differences between them, and in what applications are each used?

Why are hygienic design and washdown needed?

The consumer, and more specifically, the health of the consumer is the core concern of the food and beverage industry. Contaminated food can pose a danger to life and limb. A product recall damages the image of a company, costs a lot of money and as a worst case scenario can lead to the complete closing of the company. To prevent such scenarios, a producers primary objective is to make sure that the food is safe and risk-free for the consumer.image 1

In food manufacturing and packaging plants, a differentiation is made between the food area (in direct contact with the product), the spray area (product-related) and the non-food area. The requirements of the machine components are different depending on which area they are in.

The Food Area

In the food area the food is unpacked, or partially unpacked, and particularly susceptible to contamination. All components and parts that may come in contact with the food must not adversely affect this, e.g. in terms of taste and tolerability.

The following needs to be considered to avoid contamination:

  • Hygiene in production
  • Use of food contact materials
  • Food-grade equipment in Hygienic Design

These requirements result in the need for components that follow the hygienic design rules. If the component supplier fulfills these rules, the machine manufacturer can use the components and the producer can use the machines without hesitation.

Hygienic Design

Many component suppliers offer different solutions for hygienic design and each supplier interprets the design differently. So what does hygienic design mean? What must be included and which certifications are the right ones?

  • The material used must be FoodContact Material (FCM). This means that the material is non-corrosive, non-absorbent and non-contaminating, disinfectable, pasteurisable and sterilizable.
  • Seals must be present to prevent the ingress of microorganisms.
  • The risk of part loss must be minimized.
  • Smooth surfaces with a radius of < 0.8 μm are permitted.
  • There must be no defects, folds, breaks, cracks, crevices, injection-molded seams, or joints, even with material transitions.
  • There must be no holes or depressions and no corners of 90°.
  • The minimum radius should be 3 mm.

Supporting institutions and related certifications

There are different institutions which confirm and verify the fulfillment of these rules. They also support the companies during the development process.

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EHEDG – The European Hygienic Engineering and Design Group offers machine builders and component suppliers the possibility to evaluate and certify their products according to Hygienic Design requirements.

image33A – 3-A Sanitary Standards, Inc. (3-A SSI) is an independent, non-profit corporation in the U.S. for the purpose of improving hygiene design in the food, beverage and pharmaceutical industries. The 3-A guidelines are intended for the design, manufacture and cleaning of the daily food           accessories used in handling, manufacturing and packaging of edible products with high hygiene requirements.

image4FDA – The Food and Drug Administration is a federal agency of the United States Department of Health and Human Services, one of the United States federal executive departments. Among other things, the FDA is responsible for food safety.

What does a hygienic design product look like?

Below is an example of a hygienic design product.

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  • Stainless steel housing VA 1.4404
  • Laser marking
  • Protection class IP69K (IEC 60529)
  • Active surface made of PEEK
  • EHEDG conform
  • FDA conform

Since the product contacting area is associated with high costs for the plant manufacturer and the operator, it’s beneficial to keep it as small as possible.

The Spray Area

In the spray area, there are different requirements than in the food area.
Depending on the type of food that is processed, a further distinction is made between dry and wet areas.

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Areas in the food and beverage production

Here we are talking about the washdown area. Washdown capable areas are designed for the special environmental conditions and the corresponding cleaning processes.

Washdown

Components which fulfill washdown requirements usually have the following features:

  • Cleaning agent/corrosion resistant materials (often even food compliant, but this is not a must)
  • High protection class (usually IP 67 and IP 69K)
  • Resistant to cleaning agents
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Photoelectric sensor for washdown requirements

Ecolab and Diversey are two well-known companies whose cleaning agents are used for appropriate tests:

Ecolab Inc. and Diversey Inc. are US based manufacturers of cleaning agents for the food and beverage industry. Both companies offer certification of equipment’s resistance to cleaning agents. These certificates are not prescribed by law and are frequently used in the segments as proof of stability.

The washdown component must also be easy and safe to clean. However, unlike the hygienic design, fixing holes, edges and threads are permitted here.

For basic information on IP69K see also this previous blog post.

To learn more about solutions for washdown and hygienic design click here.