Thermotron Product Test Solutions Creates a Solution for Detecting Leaks in Plastic Containers

Author(s):
Steven Petersen - Product Test Solutions, Thermotron Industries

Industry:
Basic Materials - Steel/ Lumber/ Construction, Textiles/ Fibers/ Plastics, Oil and Gas/ Refining/ Chemicals

Products:
FieldPoint, LabVIEW

The Challenge:
Developing an integrated test system for determining plastic container durability.

The Solution:
Combining a Thermotron Product Test Solutions walk-in environmental test chamber, custom Thermotron pneumatic supply and sensing equipment, and National Instruments FieldPoint hardware running NI LabVIEW Real-Time software, controlled with custom software written in NI LabVIEW.

An Advanced Testing Capability Requirement

The customer required a comprehensive testing capability to adequately assess plastic container and material viability and reliability. They needed a turn-key, automatic, and expandable system, as their existing semiautomatic system proved inadequate.

The customer contacted Thermotron Industries to provide a complete testing requirement solution. Long recognized as a premier environmental chamber supplier, Thermotron also provides complete test system integration capabilities through the Product Test Solutions group.

Solution Hardware

The Thermotron test system incorporates a specialized environmental chamber and sophisticated low-pressure pneumatic test and measurement equipment. The environmental chamber interior walls are constructed of durable stainless steel insulated with 4 in. of urethane insulation to minimize heat leak. The floor is strengthened with a stainless steel weight-spreading plate to accommodate heavy rolling loads. A high performance heating and air circulation system maintains precise temperature control to within +/-1 ºC of the desired set point.

We created the custom low- pressure pneumatic equipment using filters, regulators, manifolds, valves, and differential pressure switches. We used NI FieldPoint controls to provide intelligent control and monitoring. We built four enclosures for the low-pressure pneumatic equipment, which were attached to the environmental chamber outside walls. Because the FieldPoint hardware works in a distributed architecture, we could place the controls near the pneumatic control equipment and placed the equipment near the items under test. We reserved space on the outside of the environmental chamber for up to four additional control enclosures for future test capacity. Each equipment enclosure provides a testing zone for up to 30 test specimens (plastic bottles). For each of the 120 test stations, a valve controls the regulated test pressure application to the test specimen. Each station also employs a differential pressure switch, provided by World Magnetics, which compares the pressure applied to the test specimen with a reference pressure, supplied by a separate reference pressure regulator. If a test specimen leaks, the differential pressure switch detects the pressure loss.

FieldPoint equipment controls the valves and detects the differential pressure switch signals. An RT Series FieldPoint FP-2000 network module in each zone provides real-time control and communication. Two FP-DI-301 16-channel discrete input modules and two FP-DO-403 16-channel sinking output modules are attached to the FP-2000 module. The FP-DO-403 output modules control pressure application through the pneumatic valves and the FP-DI-301 discrete inputs are connected to the pressure switches. Convenient indicators on the FieldPoint modules indicate output and input status. We communicate with the FP-2000 network using a 100 MB Ethernet network connected to a system control PC where the operator can configure, start and monitor tests. The FP-2000 module Ethernet connectivity helps the operator monitor the test status from anywhere on the network.

Solution Software

Custom Thermotron software resides in two areas. The first area is the FieldPoint FP-2000 network module. We created the software that runs in the module with LabVIEW Real-Time and downloaded it into the module during development. FP-2000 module functions include accepting commands from the system control PC, communication of status, valve actuation, and timing, test duration timing, pressure switch detection, and automatic individual station shutdown when a leak is detected. LabVIEW software also resides on the system control PC with an operator interface for test configuration, test initiation, status display, and recording. The operator can configure and control either single or multiple test locations, start and stop tests on individual stations, and record individual test durations. Each test system zone has a separate tab on the main display, making it easy to work with a very large number of test stations.

Creating a Complete Turn Key Solution

This test system is an example of a complete test system integrator turn key solution. Using Thermotron, National Instruments, and other quality suppliers, the result is a cost-effective test system that automates a previously labor intensive process in a way that can be expanded for future requirements.

For more information, contact:

Steven Petersen

Senior Inside Sales Engineer

Product Test Solutions, Thermotron Industries

Tel: (616) 393-4580

Fax: (616) 392-5643

E-mail: spetersen@thermotron.com

 

 

 

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