Level Measurement in the Food Processing Industry

Level sensors and controls are crucial in industrial food processing and production facilities to ensure quality and consistency. These devices monitor and regulate the level of liquids, solids, or granular materials in containers, vessels, or silos. Here are some of the most common types of level sensors and controls used in the industry:

1. Capacitive level sensors: These sensors detect changes in capacitance caused by the presence or absence of material (liquid or solid) in a container. They measure liquids, powders, or granular materials levels in various applications, including food and beverages.
2. Ultrasonic level sensors: Ultrasonic sensors use sound waves to measure the distance between the sensor and the material's surface. These sensors are non-contact and used for measuring levels of liquids or solids in tanks or silos and provide the food industry with accuracy and reliability.
3. Radar level sensors: Similar to ultrasonic sensors, radar level sensors use radio waves to measure the distance between the sensor and the material's surface. They are also non-contact and suitable for liquid and solid materials. Radar sensors are particularly useful in challenging environments with dust, vapor, or foam, making them ideal for food processing applications.
4. Hydrostatic pressure level sensors: These sensors measure the pressure exerted by the liquid column on the sensor at a specific depth. The pressure re-calibrates to a level measurement. They are primarily used for measuring liquid levels in tanks and have broad use in the food and beverage industry.
5. Float level sensors: Float sensors use a floating device to detect the liquid level in a container. The float's vertical or tilting movement triggers a mechanical or electrical signal indicating the liquid level. Food processing plants often use them for simple and cost-effective level measurements.
6. Vibrating or tuning fork level sensors: These sensors use a vibrating probe or tuning fork that changes its vibration frequency when it comes into contact with a material. They can detect the presence or absence of material and provide point-level detection of liquids, powders, or granular materials.
7. Optical level sensors: Optical sensors use infrared or visible light to detect the presence or absence of a material at a specific level. They are suitable for various materials, including liquids, powders, and solids, in food processing applications where minimum contact with the material is essential.

The choice of level sensor and control system depends on factors like the process material, the required accuracy, the process conditions, and the specific application within the food processing facility. Each technology has advantages and limitations, so careful consideration is needed to select the most suitable option for each application.

For more information, contact:

Piping Specialties, Inc.

https://psi-team.com

800-223-1468

SIL Level Switch Is Specifically Designed for Floating Roof Tanks

One of the most difficult and critical applications is measuring the high alarm or potential overfill condition on a floating roof tank containing liquid petroleum products such as crude oil or refined products such as fuel. It normally is comprised of a cylindrical steel tank equipped with an internal or external floating roof, that floats on the surface of the stored liquid. Floating roof tank systems are especially beneficial in eliminating the evaporative losses of the liquids. As opposed to a fixed roof tank there is no vapor space in the tank. This helps to reduce risk in highly explosive vapor environments. This is an extremely high cost of failure application, and one in which only the safest and most trusted products are accepted.

Safe operation of the tank farm relies on critical real time continuous level measurements of the liquids in the tank, as well as detecting when a high level condition exists. Products used in this application are typically required to meet the API 2350 Overfill Protection Standards, as well as SIL Safety Integrity Level performance standards to IEC 61508.

The challenges to reliably detect a high level condition on a floating roof tank are long sensor length requirements, and the variability of what is being measured. The floating roof may be dry in which case you need to detect the position of the physical metal roof. Or there may be a few inches of rain water or petroleum liquids on the roof. Measuring instruments need to determine very accurately, usually within a few millimeters, when the position of the floating roof has reached

The Drexelbrook SIL IntelliPoint capacitance probe level switch is specifically designed for Floating Roof Tanks (internal and external roofs) with a flexible brass level sensing probe. The level probe sensing element is field adjustable for lengths up to 15' (4.6 m). Electronics are designed to meet API 2350 Overfill Protection.

This level measurement system is specifically designed for spill prevention in floating roof tanks (internal and external roofs) using the IntelliPoint level switch with a flexible level sensing element for ease of installation (model 700-0005-595).

This level measurement system meets API 2350 regulations. It is ideal for use in safety related systems with requirements for functional safety for SIL2 in accordance to IEC61508-2, ed2, 2010 (Exida).

To prevent false alarms this level measurement system automatically recognizes and ignores coatings and is supplied with continuous self-test monitors circuits and sensing elements to detect faults.

A dual compartment housing separates the customer wiring from the sensing element and operating circuits. The encapsulated power supply/terminal block design eliminates the possibility of damage caused by moisture in the conduit.

The Floating Roof Tanks system comes with field adjustable lengths from 1' to 15' (0.3 to 4.6 m).

The system is based on our Manual Certify principle which allows the entire system to be manually tested without removing the sensor from the tank. The Manual Certify test checks that the Auto Verify circuits are operating and confirms the probe and cables are properly connected. Furthermore, the Manual Certify feature allows the electronics to sense changes in the probe that simulate contact with the media or floating roof. This provides the user with a method to ensure working performance without having to climb the tank.

No calibration or setpoint adjustments are required.

Key Features

• Loop or Line Powered
• Wetted Parts: 316SS 3/4" NPT Mounting, 3/16" FEP insulated flexible and adjustable cable, non-sparking brass sensor.
• Automatic and local or remote manual test functions ensure proper system operation.
• One system fits most floating roof tank applications, reducing field spans
• Adjustable insertion lengths up to 15' (4,6m)
• Excellent trip point accuracy over a wide range of medias and tank roof

Piping Specialties / PSI Controls

https://psi-team.com

800-223-1468

Industrial Thermowell Process Connection Types

This video covers the common types of thermowell process connections. The styles are referred to by what their process connection is.

The types are threaded thermowell, a flanged thermowell, a welded or weld-in thermowell, and a sanitary thermowell.

Threaded thermowells are commonly used when thermowell removal occurs infrequently. These wells are typically threaded into a welded fitting widely referred to as a weldolet on the pipe or vessel. Typical installations include smaller pipes or vessels where corrosion is not an issue.

Flanged thermowells are the preferred well for applications that require frequent removal or replacement due to corrosion or other hazards. Flanged wells will bolt to a mating flange installed on the process piping. Typical installations include large pipes with high pressure and high corrosion.

Weld-in thermowells are welded directly to the pipe or tank and provide a high-quality connection. Because being welded in, their removal is not easy, and they should only be installed when quick access is not required, and corrosion is not an issue. Typical installations include very high temperature and high-pressure applications, for example, a steam line or other non-corrosive applications.

Sanitary thermowells are generally fitted with a Tri-clamp or other clean-in-place connection. These thermowells also have a smooth surface which allows for easy cleaning and prevents contamination of the process: typical installations include dairy, food processing, and pharmaceutical industries.

Piping Specialties / PSI Controls

https://psi-team.com

800-223-1468

Water Cut Meters from Drexelbrook

The water cut is the proportion of water collected in a well to the total liquids produced. As crude oil and hydrocarbons travel through a pipeline, a water cut meter monitors the amount of water (cut). BS&W is the amount of non-hydrocarbon contaminants, dirt (sediment), and water included in a crude oil shipment. The lower the BS&W, the better.  Water content determination and BSW have been a persistent and long-standing issue for the oil and gas industry.

Water cut meters measure the water cut (or BS&W) of oil flowing from a well,  a separator, crude oil transfer in pipelines, and tanker loading. 

Drexelbrook has been the global leader in capacitive-based water cut measuring. Drexelbrook has the industry's highest pressure and temperature ratings, and their capacitive probes can withstand pressures of up to 1500 psi and temperatures of up to 450°F. 

The Universal IV CM Series from Drexelbrook is a high-quality water cut meter with a range of 0-50 percent in light oil and 0-80 percent in heavy oil. 

The Universal IV CM Series builds upon Drexelbrook's expertise in RF Admittance, which enables the electronics to disregard paraffin and other coatings that accumulate on the probe. 

The Universal IV CM has a one-of-a-kind Cote Shield built into the Universal IV CM series and allows the instrument to disregard a pre-determined length of the sensing element. It contains a Perm-A-Seal sensing device that eliminates the need for epoxy coatings, which wear out and need costly maintenance. 

Field setup is available anywhere along the two-wire loop when using this water cut meter with Drexelbrook's HRTWin or the STExplorer PC program. 

Choose the Universal IV CM sensing element depending on pipe size, wetted portions, NACE requirements, and pressure/temperature requirements. Drexelbrook has a broad assortment of probes to suit almost any purpose. 

All water cut meters have a built-in LCD and keypad, are pre-calibrated at the manufacturer, and need just one point confirmation. 

The Universal IV CM water cut meter is intrinsically safe and approved for Class I, Division 1, and Zone 0 hazardous areas.

For more infomration in New England, contact Piping Specialties / PSI Controls. Call 800-223-1468 or visit https://psi-team.com.

Food Industry Batch Level Control

Many food processing facilities employ batch processes in their production facilities where the operator starts with an empty vessel and create the final product by adding multiple ingredients.

The batch process requires the operator to know the amount of each ingredient added to the blending vessel. Point-level controls speed the process by establishing setpoints at each ingredient fill point,  often accomplished with several level sensors, each detecting one ingredient.

Batch food processing applications are challenging. The sensor must include sanitary fittings and CIP (Cleaned In Place) design. In many cases, the ingredients and final products are dense and sticky, wreaking havoc on some technologies such as mechanical switches and tuning forks. Products in the blending vessel may be thick and could cause damage to fragile sensors. Finally, many batch processes are agitated, causing false tripping due to splashing material. 

As you can tell, proper level sensing technology is critical. Choosing the wrong technology will cause ruined batches, costly downtime, and the possibility of overfilling.

The Drexelbrook Multipoint II offers the best solution for batch process control applications in the food industry.

Drexelbrook, a leading manufacturer of level controls, recommends its RF Admittance Multipoint II. It provides a total solution for the batch processing of food. The RF Admittance Multipoint II is a single sensing element and a single mounting point from the top of the vessel using a sanitary Tri-Clamp fitting and has no moving parts to wear out or get hung up. The Multipoint II sensor is a 3A sanitary designed steel rod with Kynar or TFE insulation developed for CIP procedures. RF Admittance Cote-Shield driven shield circuitry ignores heavy coatings on the sensing element, preventing false alarms. The Multipoint II consists of three independent DPDT relays, and control points are set anywhere along the vertical sensing element.

Drexelbrook Multipoint II Advantages:

• 3A designed sanitary sensing elements
• No moving parts
• 3 control points on one vertical sensing element
• Cote-Shield circuitry eliminates false alarms due to coatings
• Designed to endure Clean In Place (CIP) demands

For more infomration in New England, contact Piping Specialties / PSI Controls. Call 800-223-1468 or visit https://psi-team.com.

Level Measurement Solutions for Water Treatment

Several functional level measurement technologies have viable solutions for a broad range of industrial and municipal water treatment applications. Because of the variety of applications that exist and the varying application conditions, no one technology is best suited in all cases. 

POINT LEVEL VERSUS CONTINUOUS LEVEL INSTRUMENTS

Regardless of the application, there are two significant classifications of level measurement instrumentation: point level and continuous level measurement.

Point Level (On/Off) measurement indicates the absence or presence of level at a certain threshold (point) within a vessel.  Point-level switches perform as high level and spill prevention alarms, low level, pump protection alarms and pump control.

Continuous Level (Proportional) measurement indicates the level in a vessel over the full span of capacity.  These devices perform as process control as well as inventory control and management.

LEVEL CONTROL TECHNOLOGY CHOICES

The technologies used to measure level are affected differently by the varying process conditions. Below is a brief description of the different technologies commonly used in a water treatment facility.

RF ADMITTANCE/CAPACITANCE
RF Admittance/Capacitance employs a radio frequency signal and monitors for a change in capacitance. Either the presence or absence of material or how much material is in contact with the sensor, making it highly versatile and a right choice for a wide range of conditions and materials for point or continuous level measurement.

RADAR
Radar utilizes either Pulsed Wave or Frequency Modulated Continuous Wave (FMCW) through-air transmission that allows for an accurate non-contact reading of reflected electromagnetic signals.

MAGNETOSTRICTIVE
Magnetostrictive uses an electric pulse from ferromagnetic wire to accurately detect a float's position with embedded magnets.  As the pulse intersects the float's magnetic field, a second pulse reflects an electric circuit that accurately determines the distance and thus the level position.

CONDUCTIVITY SWITCHES
Conductivity switches measure the drop-in resistance when a conductive liquid contacts with two probes or a probe and a vessel wall.

ULTRASONIC (POINT LEVEL)
Ultrasonic (Point Level) measurement electronically resonates a crystal at a fixed frequency to generate sound waves that travel across an air gap to a second crystal.  As liquid fills the gap between the two crystals, the second crystal begins to resonate with the first.

ULTRASONIC (CONTINUOUS LEVEL)
Ultrasonic (Continuous Level) measurement uses a transmitter to generate an ultrasonic pulse and measures the time it takes for a reflected signal to return to the transducer to determine a liquid level.

GUIDED WAVE RADAR (GWR)
Guided Wave Radar (GWR) utilizes a Time Domain Reflectometry (TDR) technique by sending a highly focused electronic signal down a metallic rod or flexible cable waveguide. When the transmitted signal intersects the liquid's surface, it reflects along the rod or cable to determine the distance traveled. The level position is then easily inferred.

HYDROSTATIC
Hydrostatic measurement immerses a pressure transmitter with a sensing diaphragm and a sealed electronic circuitry that transmits an analog signal proportional to the liquid level above the sensor.

FLOAT SWITCHES
Float switches rely on a low-density float mounted in a vessel that magnetically couples to a limit switch. A change in fluid height actuates a switch by moving the float.

VIBRATION/TUNING FORK
The Vibration/Tuning fork is piezoelectrically energized and vibrates at a frequency of approximately 1200Hz, and as the process media cover the fork, the frequency shifts. The internal oscillator the frequency shift by and converts it into a switching command.

POINT LEVEL SOLUTIONS

Advanced RF Admittance/Capacitance point level devices are the most versatile of the point level technologies, especially with process media that can coat the sensor. They provide excellent spill/overfill protection. They are simple to install and have no moving parts, making them virtually maintenance-free. Their robust design and circuitry make them an ideal solution for many water treatment applications.

Both tuning forks and ultrasonic gap switches provide reliable high- or low-level measurements in various applications. For non-coating conductive liquids, conductivity switches provide economic priced measurement while float switches appear in many basic applications at very cost-effective prices.

CONTINUOUS LEVEL SOLUTIONS

Mechanical systems such as floats and bubblers require extensive maintenance and are less reliable and accurate than electronic systems. Hydrostatic systems afford better reliability and are simple to use, and can transmit data to another receiver for remote monitoring, recording, and control.

RF Admittance/Capacitance level is a time-proven and one of the best available technologies for indication and control. RF technology inherently provides the highest accuracy and repeatability in interface measurements. Variations in the makeup of upper and lower phases of a liquid have no appreciable effect on system accuracy. Recalibration is not required.

For short-span measurements, RF Admittance technology provides one of the most preferred readings. As the level of measurement span decreases, the more appropriate RF technology becomes. In spans of only a few inches, RF systems can repeatedly produce accuracies of 1/32ths of an inch. RF has the added benefit of not being limited by “dead zones” inherent with many popular technologies often selected for measurement ranges larger than 5 feet.

Non-metallic tanks pose no technical problems for Ultrasonic, Magnetostrictive, Hydrostatic Pressure, Radar, and GWR (Guided Wave Radar) technologies. The GWR approach is suitable for vessels with internal obstructions and uses lower energy levels than airborne radar technologies. Non-contact technologies, such as Radar and Ultrasonic, can have measurement ranges up to 130 feet. 

For long-range measurements or headroom limitations, flexible sensors offer insertion lengths up to several hundred feet for Hydrostatic Pressure and RF Admittance technology products. Loop-powered GWR (TDR)-based products allow measurement ranges up to 115 feet in selected applications. Magnetostrictive technology provides an accuracy of 0.1% of measurement span in flexible sensor designs up to a maximum range of 70 feet.

Piping Specialties / PSI Controls

https://psi-team.com

800-223-1468