Measurement made easy Web tension systems Quality tension measurement for quality tension control

 • Accurate • Rugged • Reliable

Pressductor PillowBlock load cells 

Introduction

ABB’s Pressductor® PillowBlock load cells are sensitive and accurate yet rugged, reliable and compact. The performace of the Pressductor PillowBlock load cells is unsurpassed for paper mill applications characterized by heavy rolls, high speeds and severe conditions – in some instances they are the only viable option. They can withstand high overloads and vibrations, and operate over a wide range of tensions. 

The well-proven Pressductor load cells combined with the tension electronics, offer an easy-to-use/ user-friendly web tension measurement system with superior long term performance leading to higher productivity and product quality and higher profit for the web producer.

Increased process uptime 

In a web process running continuously, every minute of production time is precious. Even so, no production line runs without downtime. With Pressductor PillowBlock load cells the risk of web breaks can be reduced to a minimum, thus leaving as much time as possible for real production.

Thanks to a strong and stable signal deriving from the Pillow-Block load cells, the upcoming web breaks are kept to an absolute minimum level.

Tighter product tolerances

The ability to produce web to tighter tolerances minimizes the costs associated with nonconforming web. It also increases the web producer’s accessible market to include products with tighter tolerance requirements.

Pressductor PillowBlock load cells 

Ideal for paper and converting industry

Designers appreciate: • Remarkably high spring constant • Wide measurement range • High reliability

Operators value a load cell with: • No drift • No need for recalibration • No failures • High reliability

Measurement essentials 

Keeping the tension constant in web processes is essential for high product quality and productivity. Continuously measuring the tension is an obvious prerequisite for tension control. Drives and operator instruments need quick and accurate input to regulate tension levels and monitor machine performance

Most web processing lines put a premium on long-term reliability, in addition to accuracy and overall performance. The measurement system, after all, is the front line of machine control, exposed to all the rigors of the operating environment. The costs associated with downtime and poor product bring out the true value of its components.

Quality measurement technology for superior tension control that will keep your processing lines productive and producing top-notch output – that’s what you can expect from us. We’re entirely devoted to providing process measurement systems and services, and we have 60 years of experience in the field. We are the experts in web and strip tension as well as force measurement for virtually any purpose

Selecting and sizing load cells 

The two types of ABB PillowBlock load cells are designed for either conventional vertical force measurement or for sensing the horizontal force component that may arise as the processed material partially wraps around a measurement roll.

Using the horizontal load cells can be quite advantageous. By design, they can be made exceptionally sturdy, rugged, and stiff. So, requirements for recalibration, other maintenance, or replacement are negligible, and they do not contribute to machine vibration. Since they don’t measure the tare weight, but just the horizontal force component of the web tension, they can be sized smaller than otherwise possible, measuring tension with greater accuracy.

Extended-range operation 

An extended range of measurement beyond the nominal load allows the PillowBlock to be sized for normal, as opposed to maximum tension levels. As a result, they permit greater application flexibility on the processing machinery.

Application requirements may dictate the selection of a vertical load cell. But whenever an adequate horizontal force component is present (or can be developed), the horizontal load cell should be considered. 

The size, or nominal load, of a load cell is contingent on the anticipated force it will measure. When a vertical load cell is mounted horizontally (the most common arrangement), the measurement force (FR) is a function of the tension in the web (T), the deflection angles (α and β), and the tare weight of the roll and bearings (Tare). 

The horizontal load cell senses the web tension’s (T) horizontal component (FR); not the vertical force (FV). 

In this scenario, the measurement force (FR) is a function of only the tension in the web (T) and the web angles (α and β). Since the tare force (the weight of the deflector roll and bearings) will not be measured, it can be very large compared to the web tension without affecting the accuracy of the tension measurement.

Specifying the load cell 

Since load cells are typically used at both ends of a roll, rating the individual cell is usually based on half of the resultant force. The ideal load cell size is usually the smallest nominal capacity rating accommodating that force level, so long as the force exceeds 10 % of the nominal load. Before choosing a larger size, however, consider using the extended range feature of ABB load cells. And always verify that overload specifications will not be exceeded in either direction.

Application hint Two 10 % application guidelines are useful in selecting load cell sizes: 

1. The proportion of web tension that is actually sensed by the load cell should be at least 10 % of total web tension. For operational conditions producing values below 10 %, consult ABB.

    2. During normal operation, the sensed force should not be less than 10 % of the load cell’s capacity

PFTL 101 Horizontal force measurement, 0.5 to 20 kN

PFTL 101A/AE/AER PFTL 101B/BE/BER

PFTL 201 Horizontal force measurement, 10 to 100 kN

PFTL 201C/CE PFTL 201D/DE

PFCL 201 Vertical force measurement, 5 to 50 kN

PFCL 201C/CD/CE

PFEA – the compact solution

All three versions have multi-language digital display and configuration keys. The configuration keys being used for setting different parameters and to check the status of the tension system. The 2 x 16 character display can present sum, difference or individual load cell signals. All three versions are available in both DIN-rail version and enclosed IP65 1 version for mounting in more severe environments.

PFEA 111 

A cost effective, compact and user-friendly tension electronics providing an accurate and reliable fast analog SUM signal from two load cells for control and/or monitoring. The display can show the SUM, individual A & B and difference signal. The small size and DIN-rail mount make this unit very easy to integrate into many types of electrical cabinets.

PFEA 112 

This unit provides the same functionality and user friendliness as the PFEA 111 with the addition of fieldbus communication via Profibus-DP.

PFEA 113 

This advanced tension electronics can supply up to four load cells and has six configurable analog out-puts for control and/or monitoring of web tension. The output signals are also available on Profibus-DP.

Another useful feature is the possibility to, via the digital input or Profibus, switch the gain for two different web paths. Alternatively, the digital input could be used for remote gain scheduling or zero set. This unit also includes a self-diagnostic function and four configurable digital outputs for alarms and level detection. Status of self-diagnostic functions are also available on Profibus-DP.

By combining up to three PFEA 113 the system can handle segmented roll applications, i.e. winders, with up to 12 load cells.

The high level of functionality and user-friendliness make the PFEA 113 one of the most complete tension electronics on the market.

PFEA 111 PFEA 112 PFEA 113