A Quarterly Newsletter of Parr Instrument Company | April 2017 | Vol. 4 No. 1
Features and Benefits
Parr’s First PC Controlled Calorimeter
|Released in 2015, the 6050 Compensated Jacket Calorimeter is the first Parr calorimeter that does not feature a built in controller. Instead, the 6050 is conveniently controlled by a PC or a Windows® based tablet via the included USB cable. System requirements are minimal. Any PC or tablet that runs Windows® 7 or newer should be able to run the 6050. Multiple 6050 Calorimeters can be operated with a single PC.|
Point and Click
The menus and actions for the 6050 are user-friendly with a point and click interface. Drop down menus are used when there are multiple options available. Menus are organized on tabs allowing quick access to the functions desired.
The 6050 is capable of printing to any printer installed on the PC or to a 1758 Printer available separately.
The 6050 Compensated Jacket Calorimeter is positioned between our educationally-focused 1341 Plain Jacket Calorimeter and the 6100 Compensated Jacket Calorimeter. The 6050 is an economical unit for those customers that do not need the full precision and accuracy of the isoperibol calorimeters.
Bolt Loads and Gasket Compression
Parr commonly uses gasketed joints in its pressure vessels.The gaskets used in such vessels are typically made out of flexible graphite or PTFE. Bolts made out of various materials of construction (depending on application) are typically used to “load” or “energize” such gaskets.
As a practical matter, in order for a gasketed joint to provide a leak-free performance, bolts are used to apply a net load to perform the following two basic functions:
- resist the hydrostatic end force (H) – this is the force needed to resist the net load due to internal pressure being applied on the area within the seal diameter
- provide an additional load (G) for gasket seating – this load helps maintain a residual stress on the gasket under operating conditions to ensure that the gasket will be in continuous intimate contact with the gasket seating surfaces to prevent leakage
The total force necessary to deliver a leak-free performance during operating conditions may be obtained as follows: Total Force, F = H + G.
Whereas the force H can be calculated fairly easily using readily available formulae, calculation of the force G requires knowledge of gasket properties. These include factors such as gasket width and gasket material, among others. In particular, the factor that generally impacts users of Parr vessels in the most practical manner, is the gasket material.
The contribution of load G on total load F can vary from zero (for self-sealing o-ring designs) to roughly five times the load H (for solid metal gaskets). While these are the two extremities of seals used on Parr vessels, factors used when PTFE and flexible graphite seals are used depend on the application. PTFE seals are generally easier to use than flexible graphite seals since the additional load needed for seating PTFE seals is much lower than that needed for flexible graphite seals. Consequently, bolts on a vessel with a flexible graphite seal would need to be loaded to a higher value when compared to a scenario in which a PTFE seal is used for the exact same application and working conditions.
The sealing load applied to bolts used on Parr vessels are typically controlled using a torque value. Standard torque values for most vessels are included within the operating instructions furnished with the shipment. For special/custom rated vessels, recommendations for torque ratings are supplied in the form of supplemental instruction sheets.
Other than model-specific operating instructions, the following is a non-exhaustive listing of other Parr resources from which torque ratings may be obtained:
- 285M: Torque ratings for various vessels utilizing flexible graphite gaskets
- 231M: Torque ratings for safety rupture disc holders
- 539M, 579M: Torque ratings for round/oblong window assemblies
- 661M, 687M, 490M: Torque ratings for Parr manufactured bottom drain valves
- 708M: Torque wrench corrections for when extensions are used
A final consideration worth noting here is that while the use of torque values to control bolt load is relatively user friendly, it is certainly not the most accurate method. One of the key factors that can greatly impact the net load transmitted when a bolt is tightened via the torqueing process is friction at the mating threads. It is critical to ensure that mating threads are well lubricated prior to torquing. In this regard, Parr recommends use of a high temperature anti-seize lubricant (Parr Part # 424HC2 or equivalent) for most applications.
Device Control – Simplified
In order to control a device of almost any type, the overall control scheme can be depicted by this graphic:
The nature of the Sensor and Actuator will change depending on the device to be controlled. For example:
|Device||Sensor||Actuator||Input to Actuator|
|Valve (NO / NC)||Power on||Solenoid valve||Air|
|Valve (Control)||Flow or pressure||I/P||Current / Air|
|Pump||pH probe||Motor||Liquid acid|
If the device to be controlled is a heater, the temperature controller will compare the thermocouple input to the set-point. If the actual temperature is below the set-point, the controller will output a signal to tell the actuator to turn on. In this case, the actuator is a solid state relay that, when turned on will allow a voltage input to pass through to the heater.
If the device to be controlled is a Back Pressure Regulator (BPR), the pressure controller will compare the transducer input to the set-point. If the actual pressure is above the set point, the controller will output a current (I) signal to the actuator (I/P converter) which will send a proportional air pressure to the air-actuator on the BPR adjusting its setting to allow more gas to escape the system thus lowering the pressure to match the set-point.
Hydrothermal Synthesis in Acid Digestion Vessels
In addition to their normal uses for sample digestion and dissolution, Parr’s Acid Digestion Vessels serve as excellent general purpose reactors for procedures requiring a small PTFE lined vessel for use within prescribed temperature and pressure limits. Agitation can be produced by a magnetic stir bar or by shaking or rolling the vessel.
These vessels have proven to be an excellent means to perform hydrothermal synthesis. Hydrothermal synthesis is a technique that involves the growth of materials from aqueous solutions at elevated temperature and pressure. The term hydrothermal usually refers to any heterogeneous reaction in the presence of aqueous solvents and complexing agents under high pressure and temperature conditions to dissolve and recrystallize materials that are relatively insoluble under ordinary conditions. The hydrothermal technique is widely used for the synthesis of a variety of inorganic compounds, nanomaterials and zeolites. It is a highly interdisciplinary subject and the technique is popularly used by geologists, biologists, physicists, chemists, ceramists, hydrometallurgists, material scientists, engineers, and many others.
The use of Parr Acid Digestion Vessels for hydrothermal synthesis is described in many research articles. Download a selection of these reference articles here.
Parr Team Member Focus
Dan Yaeger, Engineering Project Manager & IT Manager
Dan attended Bradley University in Peoria, Illinois for his undergraduate studies where he double majored and received B.S. degrees in Business Computer Systems and Multimedia in 2004. Currently, Dan is enrolled in the M.B.A. program at the University of Iowa.
Originally from the south suburbs of Chicago, Dan moved to the Quad Cities in 2006 to join Parr as a member of our IT Department. Since then, he has become a Certified ISO Internal Auditor and moved to our Engineering Department. In 2015 Dan was promoted to Engineering Project Manager and last year he was also given the role of IT Manager.
Dan’s job duties include providing great customer service to people within and outside of Parr. He directly impacts external Parr customers by managing orders that require custom engineered products. He impacts internal employees, Parr dealers, and external customers by maintaining and implementing new IT systems to make daily operations and interactions more efficient and feature rich.
When talking about his career at Parr, Dan said he “…enjoys the variety of tasks and the ability to use a wide array of skills to accomplish all customers’ (internal and external) requests. Every day presents a different challenge and that is what makes it exciting to be a part of this unique Parr Team.”
Outside of Parr, Dan enjoys doing home improvement projects, woodworking, electronic tinkering, and camping. His highest priorities include spending time with his family, his wife Beth, their daughter Amelia, and the family dog Wrigley (named after Wrigley Field, home of the Chicago Cubs).
Inside and out of Parr, Dan is always working hard to make sure everything is running smoothly. We are thankful to have him on our Parr Team!
April 18-21, 2017
Look for our representatives from MK Science Co., Ltd.
June 4-9, 2017
View our complete 2017 Trade Show schedule.