The viscosity or more accurately the rheology of fluids is a dominant parameter for accurately calculating the heat transfer and pressure loss characteristics in plate heat exchangers. Food products have a diverse range of rheological characteristics that are uniquely formulated for particular sensory experiences by each manufacturer. Rheology equations for use in heat exchanger calculations are ideally developed using a rotational rheometer with the geometry precisely controlled to yield the most accurate absolute viscosity measurements. The use of product specific rheology equations in the prediction of plate heat exchanger performance produces the best results for the processor.  Processors that have products with high solids will want to have their products tested in the R&D facility in Portland, OR.  This test is accomplished on a viscometer that can test across a wide range of temperatures and various shear rates yielding a precise mathematical equation for the product.  After testing the data can be incorporated into AGC’s special plate sizing program for real world solutions.

For more information on Testing for Leaks and the AGC PlateCheck™ call AGC Engineering at 800-825-8820 (Eastern Factory) or 800-715-8820 (Western Factory).

In the last 10 years, processing plants have seen the benefits of following the 3A recommended practice of testing their plate heat exchangers at regular intervals.  But what method should be followed and with what frequency?  Who is qualified to perform the inspection and what will they look for when the unit is opened?

Frequency of testing -  There appears to be a practical standard in the industry of testing all plates at least once per year especially if the plates have been in service more than three (3) years.  This is assuming the plates were NEW.  If the plates were exchanged (reconditioned), you most likely have a mixture of old and new plates, and you should continue to test at least once per year.

Field Inspection Methods - There are several methods of testing for pin-holes some take more time and are not practical.  For example,  visible red/white spray or using a florescent  penetrant and a black light. 

About 13 years ago the big factories were charging hundreds of dollars per plate to inspect, clean and regasket plates.  Most processors could not afford the cost or the down time and would try to inspect plates in-house by spreading the plates out in a raw milk receiving bay or warehouse.  Then they would spray them or coat them with dye and inspect often times with mixed results.   Other methods have proven ineffective like conductivity / Ultrasonic type or using helium gas.  There are even some people who circulate Potassium Permanganate which is very reactive and requires heat and a special acid procedure to remove plate staining.  A simple bubble test is good but proves ineffective unless large pin-holes or cracks are present.  To be sure of an accurate test, processors need two things.  First, a trained and experienced technician/engineer who knows the wear characteristics and functionality of plates.  Second, the unit must be opened and visually inspected to determine CIP effectiveness, plate wear, gasket condition, etc.  Opening the frame is not always popular with operators, but there is no other way to completely check the unit.

PlateCheck™ Food Grade Circulate Dye Method - This method was developed and perfected by AGC Engineering over 14 years ago to accurately test a complete unit (large or small) in a matter of hours.  Dean Foods- southeast region uses PlateCheck™ as there only approved leak check procedure, as other methods have proven largely ineffective.

AGC has proven you cannot completely and properly check a plate heat exchanger without opening the unit at least once to visually inspect the plates.

What you miss – If you try to inspect a unit without opening it you will not check approx. 15-20% of the plates.  Most importantly you will not inspect product contact surfaces for CIP (clean-in-place) response, gasket condition, plate corrosion or frame condition.  On several occasions, AGC has re-inspected units previously tested using the ‘other methods’ and found numerous plate pin-holes and other discrepancies.   In a review of several recent leak check inspections using the PlateCheck™ circulate methods, we found an average of four major discrepancies like poor cleaning, plate corrosion, gasket wear and frame damage (see below)

The Platecheck method using a water soluble, inhibited food grade dye -AGC RI-606.  This dye method can consistently find plate pin-holes or cracks as small as 3 microns.  The dye is circulated in one complete circuit, on one side of the plates, under pressure using AGC’s portable field test equipment.  AGC can typically test a unit in as little as 3 hours and more than one unit can be inspected in one 8 hour visit.  A written report of the findings is provided for plant records or to show Federal or State inspectors.  PlateCheck™ meets the 3A recommended practice for testing plates. 

For more information on the features of the Pro5Plus™ plate call AGC Engineering at 800-825-8820 (Eastern Factory) or 800-715-8820 (Western Factory). 

Customers are benefiting from the annual PlateCheck™ inspections being performed at dairies all over North America.  In the last 10 years, processing plants have seen the benefits of following the 3A recommended practice of testing their plate heat exchangers at regular intervals.  Inspection items include 100% plate inspection for pin-holes, corrosion, excess wear and gasket condition.  Also, a check to see if the plates are installed correctly and a detailed analysis of CIP (clean-in-place) response.  Finally, the frame is inspected (including terminals, dividers and ports) for structural ingtegrity.  Customers find this test very valuable in many ways.

“I like the detailed reports because I’m able to trend (year over year) how the unit is doing and more accurately schedule and justify expenditures for maintenance.  The technicians are very knowledgeable and provide professional service.”
Scott Woodard- Mayfield Dairy- Birmingham, AL USA

“All the technicians at AGC are very knowledgeable and respond very quickly to our requests.  Because this is an egg plant the USDA dictates we do an annual inspection every 12 months.  Our local USDA inspector trusts AGC as a third-party doing the inspections.”
Raymond Truex – Crystal Lake Egg- Atwood, IN USA

“AGC’s annual PlateCheck is very accurate.  They locate and document any problems with the plates or frame.  I can’t imagine any test that doesn’t include opening and visually inspecting the plates. Their technicians also have a detailed qualification summary that I use with our SQF documentation”. 
Nick Arnold- Plant Engineer- T.G Lee Dairy- Orlando, FL

For more information on the features of the Pro5Plus™ plate call AGC Engineering at 800-825-8820 (Eastern Factory) or 800-715-8820 (Western Factory).

The current economic slump has many manufacturers cutting back.  Whether its fewer cookies in the box or no peanuts on the flight, companies of all types are giving you less and charging the same as before.  In our industry, many manufacturers are switching to thinner plate materials in a rougher finish.  They say that it is just as good, but is it really?  

It wasn’t that long ago when 0.8mm and 0.9mm thick plates were used in almost every full scale pasteurizer.  These days, the new standard from most manufacturers is only 0.6mm.  Even plates that were already 0.6mm are being downsized to 0.5mm and 0.4mm.  Clearly, this represents a considerable cost savings for the manufacturer.  The question is, “what does it cost you, the end user?”  The most appreciable loss will be in mechanical strength.  With all else being equal, a 0.7mm plate will be 35% stronger than a 0.6mm plate and 95% stronger than a 0.5mm plate.

That loss in mechanical strength will affect the pressure capability and serviceability of the plate.  This can result in blown gaskets or plates which are worn out by their first gasket change.  AGC designs their plates for the real world sanitary environment.  We understand that process hiccups will occur and the plates are over-built to accommodate that.  AGC plates are also intended to be regasketed for a second or third life, unlike many “throw away” plates on the market.  In fact, our top selling Pro5™ model still uses 0.9mm thick material.  The smaller Pro3™ and Pro2™ models haven’t changed either and still use 0.7mm thick material.

Rule of Thumb: With all else being equal, a 0.7mm plate will be 35% stronger than a 0.6mm plate and 95% stronger than a 0.5mm plate.

The same manufacturers which are thinning out their plate material are also switching to rougher finishes.  The standard plate finish in sanitary processes used to be a mirror-like bright anneal.  Silently, these plates were switched to a dull 2B finish.  Again, this represents a considerable cost savings for the manufacturer.  The difference is clear, even to the casual observer (see photo below). There is no question that surface finish plays a role in the adhesion of bacteria and fouling.  Smoother surfaces clean more effectively and stay that way longer.  Inspectors and quality control personnel appreciate the bright appearance because, unlike the dull 2B material, you can tell if the plate surface is clean after CIP.  

Popular AGC Pro5™, Pro3™, and Pro2™ plates still use the high quality bright anneal material.

AGC is one company that refuses to compromise when it comes to quality.  Plates are as thick and mirror bright as always, because it makes a better product.  Our motto has always been “Building the Best” and we don’t intend to change that.  
 

Cream is a heterogeneous mixture where the exact composition and state can vary due to a multitude of conditions imposed by seasonal, farm, and processor effects. Manufacturers’ cream consists of approximately 40% milk fat emulsified in a serum water phase.  40% milk fat Cream is typically separated from the raw milk during processing at between 130 to165 °F. The cream is then cooled in a plate heat exchanger and stored for later use or shipped out for further processing.  When cooling up to 50% of the fat portion of the cream (fat globule- see fig.1) will crystallize and change state from a liquid to a solid.  The cream tank “Bounce Back” is the latent heat of the cream being given off as the fat portion of the cream changes state or crystallizes.  Studies have indicated a latent heat value of 32 Btu/lb represents this change of state from liquid to a solid.  AGC has determined this phase change to take approximately 2 hours and will raise the overall temperature of the 40% cream as much as 8 °F.  Your cream cooler may provide cooling to 38°F or lower exiting the unit, but your cream storage tank must be able to remove this latent heat load or you may need a specially designed “post latent heat cooler” to ensure proper load out or storage temperatures.  Contact AGC with any questions you may have regarding post latent heat cooling or cream cooling in general.

For a more detailed explanation please contact AGC and ask for the paper titled “Practical considerations when cooling Cream.”

Twin Spindle Hydraulic HTST Frame and special designed plate inlet provide superior performance.

Laurel, MD- Dreyer’s Grand Ice Cream Holdings, Inc. is moving quickly in its $180 million project to triple the capacity of its Laurel manufacturing facility. On completion, it will cover nearly 700,000 square feet with expansion capability.

Dreyer’s recently received several large AGC HTST Plate pasteurizers for processing, similar to equipment already installed at the Bakersfield, CA plant.  

They selected the proven Heavy Duty AR51-H (Hydraulic) frame with the exclusive Pro5™ plate.  
 
The Pro5™ has a unique inlet design which significantly reduces the pressure drop and allows Dreyer’s to run a wider variety of mixes than older style designs.  

Also, they will be able to operate at a higher CIP (clean-in-place) flow-rate for improved cleaning performance.  The new Laurel, MD facility is the sixth Dreyer’s production plant in the U.S.A. to install the Pro5™ plate.

Ron Smith –Western Regional Manager for AGC Engineering said “Due to the inlet distribution area and expanded inlet of the Pro5™ It’s now the established standard for processing Ice Cream Mix and other viscous products.”   

The Laurel Operations Center will complement the Bakersfield, CA Operations Center in size and capacity when completed and will give Dreyer’s two of the world’s largest ice cream facilities, one on each coast of the United States.  

The Pro5™ plate can also be installed in any existing APV or Crepaco model R5 frame so processors can upgrade their existing units reducing pressure drops by as much as 35% or more and improving cleaning response. AGC is proudly American owned and manufactures all of its Proseries Plates and Frames in-house, in the USA!

For more information on the features of the Pro5™ plate call AGC Engineering at 800-825-8820 (Eastern Factory) or 800-715-8820 (Western Factory) or visit our  website at www.AGCEngineering.com  

The mission and goals of 3A sanitary standards, Inc. (a non-profit organization) include development of voluntary standards and accepted practices. Users of all types of sanitary processing equipment displaying the 3A logo know they are in compliance with all applicable sanitary codes because enforcement authorities helped develop each 3A sanitary standard. Processors know their equipment can be cleaned satisfactorily and inspections will go more smoothly when equipment complies with standards that regulatory sanitarians help formulate. Besides the five founding members the leadership of 3-A SSI includes the Food and Drug Administration (FDA), the U.S. Department of Agriculture (USDA), and the 3-A Steering committee. Workgroup 5 (Heat Exchange) is currently working on a draft (T-11-10) that includes recommended practices for Plate Heat Exchange leak testing and physical inspection. This revised standard is a great improvement over the previous standard which had no standards for testing.