AGC News

Category: General

PHE101 Course Continuing Education

Knowledge is Power

PHE101 CourseEmpower your staff with a working knowledge and appreciation of your facilities plate heat exchanger

 or PHE’s. An educated team will help to reduce equipment downtime, prevent costly mistakes, promote team work and increase equipment longevity.


AGC PHE101 Course

· Course participants will learn the basics of gasketed plate heat exchanger components, proper assembly, troubleshooting, and reading/understanding the manufacture’s drawings.

· Develop confidence and understanding by working with specific PHE’s (plate heat exchangers) in your plant.  

· Confidently verify CIP (clean-in-place) effectiveness.

· Knowledge verification test is given to satisfy proficiency training guidelines.

· Convenient on-site sessions available.

PHE101 Course Outline

· Plate Heat Exchanger Frame Basics -Hydraulic, manual, tie-bolt styles

· Plate Basics – Plate and gaskets, identification and function

· Plate arrangement and fluid flow -Understanding your specific unit flow drawings.

· Proper assembly and Troubleshooting -leaking or blowing plates, plate wear

· Inspection of PHE – Frame, Plates & gaskets as well as CIP (clean-in-place) response.

· Hands on Training – using a tabletop Plate unit and/or one of your production units.

· Knowledge Verification – Testing

*Note: course outline can be adjusted to satisfy specific plant needs and objectives. Training course approx. 4 hours in length per session.

Category: Service/Plate Checks

Field Leak Testing of Plate Heat Exchanger Plates

Plate CheckPotential problems with shelf life and product quality are reduced by a fast and reliable field leak check procedure called PlateCheck–Seeing is Believing!

By: John C. Bohn- Founder AGC Heat Transfer, Chairman 3-A WG5 -Heat Exchangers

In the last 20 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. 

Years ago plate manufacturers 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, individually inspecting each plate for pin-holes often times with mixed results.   Other methods have proven ineffective or incomplete 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 has been employed recently but it doesn’t check all the plates and is 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.  Recent 3A standards recommend annual inspection using only tests that are not dependent on the size or volume of the unit.  this eliminates the conductivity, helium and bubble tests as they are dependent on the size of the unit and do NOT treat all the plates the same.

PlateCheck™ Food Grade Circulate Dye Method –

This method was developed and perfected by AGC Heat Transfer over 20 years ago to accurately test a complete unit (large or small) in a matter of hours.  Dean Foods 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 confidential 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 field inspection using PlateCheck™ testing call AGC Heat Transfer at 800-825-8820 (Eastern Factory) or 800-715-8820 (Western Factory) or see the website at www.agcheattransfer.com 

Category: Parts/Upgrades

Plate Material – Getting Your Money’s Worth

Things to consider when comparing sanitary heat exchanger plates.
By: Corbin Behnken, Sr. Sales Engineer, B.S. in Mechanical Engineering

Plate MaterialThe 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 above). 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. 

Category: General Process Applications

Latent Heat and Cream Cooling

Knowing the characteristics of cream can aid in understanding how to store and/or ship cold cream.

By George Tholl, B.S.ChemEng. P.E.-Director of R&D- AGC Heat Transfer, Inc.

Latent Heat and Cream CoolingCream 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.

Temperature rise

 

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

Category: General Parts/Upgrades

90% HTST Regeneration: The “Gold” Standard, or “Old” Standard?

Plant Engineers and Plant Managers should consider upgrades to maximize profits.

It is estimated that over 65% of the Nation’s bottled milk plants are operating their pasteurizers at only 90% efficiency.  While 90% seems like a “responsible” level of regeneration, it is not at a level that is cost effective.  Increasing the regeneration from 90% to 92.6% will save 26% in utility costs.  With the current escalating cost of energy, it is critical to evaluate your existing HTST regeneration amounts.  The regeneration section of your pasteurizer determines the amount of energy that is recovered when the product is heated to pasteurization temperature and cooled prior to packaging. 

HTSTRegeneration is expressed as a percentage and calculated by the heat load recovered in the regeneration section divided by the total heat load required.

In the past, plate heat exchangers were designed with regeneration percentages of 89% to 90%. Nowadays, new pasteurizers are typically sized for 92% and above. An increase in 2% to 3% in regeneration can reduce operating costs and increase plant profitability.

The costs for electricity (kWh) varies by region; you can find the true cost per Kilowatt hour in your area by taking the total amount on your bill and dividing by the total kilowatts used – this will include all taxes, fees and surcharges. Some areas on the West Coast pay 12 to14 cents per kilowatt hour while other areas of the country are paying 6 cents per kilowatt hour. 

One thing is certain, the cost for electricity and natural gas will increase and it is desirable to increase your regeneration to optimize profitability.

Fact: Given any pasteurizer heating from 38-178 deg.F and cooling from 178-38 deg.F if the  regeneration is increased from 90% to 92.6% (only 2.6%) processors will realize a 26% savings in utility costs.

PlateSOLUTION- Upgrade to the Pro5Plus™ plate.  If you have a pasteurizer model CR5, R51, R56-S, R51T or similar models made by APV or Crepaco with the old style R5 plate, or if you have previously installed the AGC Pro5 upgrade in these units, you could increase your regeneration percentage from 89/90% to greater than 92% at your next scheduled maintenance by installing the AGC Pro5Plus™ plate. 

The Pro5Plus™ plate is designed with an optimized (slightly reduced) gap which allows the user to install approximately 30% more Pro5Plus™ plates in the same space thereby increasing the performance and regeneration without piping changes.

Category: General

Product Viscosity and the Plate Heat Exchanger

Knowing the product characteristics especially whether a product is Newtonian or not is key to process design.
By George Tholl – Director of R&D, (Chemical Engineering B.S., M.S), PE

Product ViscosityThe 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 Heat Transfer, Inc. at 800-825-8820 (Eastern Factory) or 800-715-8820 (Western Factory).