Posts Tagged ‘food manufacturing’

The Depositor’s Pneumatic Actuator

Thursday, June 21st, 2018

    Last time we learned that a fruit jelly depositor in a food manufacturing plant is an example of a positive displacement pump at work.  Today we’ll see how pieces of equipment on the depositor, known as a pneumatic actuators, work.   Pneumatic actuators do not come in contact with the jelly flowing through the depositor.   In other words, no jelly flows through the actuators.   The jelly only flows through the transfer valve and positive displacement pump as we saw last time.  The pump and valve can’t move by themselves.   So, they need some device to set them in motion.   That’s where the pneumatic actuators come into play.   They impart movement to the pump and transfer valve to get the jelly flowing from the hopper and down through the nozzle and onto the pastry.

    A pneumatic actuator is a device that operates using compressed air.   Compressed air, from an external air compressor, enters into a tube in the actuator known as a cylinder.   Inside the cylinder is a piston that can move along the length of the tube.   Attached to the piston is a piston rod which extends to the outside of the cylinder.

    When compressed air is introduced into the cylinder on the left side of the piston, it forces the piston and piston rod to move towards the right side of the cylinder.   But, air must be vented out to atmosphere from the right side of the piston for this movement to occur.   If no venting took place, trapped air to the right of the piston will get squeezed between the piston and the right end of the cylinder.   When the air gets squeezed, it becomes pressurized.  The pressure will impede the movement of the piston.

    Likewise, when compressed air is introduced into the cylinder on the right side of the piston, it forces the piston and piston rod to move towards the left side of the cylinder.

 The Depositor’s Pneumatic Actuator

The Depositor’s Pneumatic Actuator 

 

    So, depending on which end compressed air is admitted to the pneumatic actuator’s cylinder, the piston rod will move to the left or the right.   In engineering terms, the actuator imparts linear motion to machines.   In other words, the piston rod moves back and forth in a straight line.

    Next time, we’ll see how the pneumatic actuator is connected to the depositor’s pump to impart the linear motion that draws jelly from the supply hopper and sends it streaming out of the nozzle onto a passing pastry.

Copyright 2018 – Philip J. O’Keefe, PE

Engineering Expert Witness Blog

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A Jelly Depositor is a Positive Displacement Pump

Thursday, June 7th, 2018

    Our last blog introduced a project I oversaw while acting as a design engineer in a food manufacturing plant.   The objective was to deposit fruit jelly into raw pastry dough as it whizzed along a production line conveyor belt before being sent off for baking.   A special piece of equipment known as a depositor would be required to meet this challenge, and we’ll take a look at how one functions today.   In fact, a jelly depositor acts very much as a human heart, as they’re both examples of positive displacement pumps.

    A depositor is a device specifically made for the food industry.   It consists of a hopper to hold the product to be deposited, in this case fruit jelly, which is discharged by the hopper into a rotating diverter valve and then on to a positive displacement piston pump.   See below.

A Jelly Depositor is a Positive Displacement Pump

A Jelly Depositor is a Positive Displacement Pump

   

    When the diverter valve rotates, a passageway opens to allow jelly to flow from the hopper into the piston pump.   A pneumatic actuator, a device we’ll discuss in more depth next time, moves the pump’s piston to the left, away from the diverter valve, which allows the filling to be released into the pump from the hopper.   At the end of the piston’s travel a set quantity of fruit jelly filling is drawn into the pump’s housing, just enough to fill one pastry. See below.

The Depositor Draws Filling Into The Pump

The Depositor Draws Filling Into The Pump

   

    When the diverter valve rotates in the opposite direction, a passageway opens inside the valve that allows jelly filling to move from the pump to the nozzle.   As the piston moves back toward the diverter valve the filling is forced out of the pump, through the nozzle, and into the pastry dough.   The pump’s piston moves back and forth, that is, away from and then towards the transfer valve, ushering a set quantity of jelly filling through the mechanism each time.   See below.

The Depositor Deposits The Filling

The Depositor Deposits The Filling

   

    Now that we know how the depositor works, next time we’ll discuss the pneumatic actuator’s role in the filling process.

Copyright 2018 – Philip J. O’Keefe, PE

Engineering Expert Witness Blog

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Positive Displacement Pumps Are Used in Industry

Tuesday, May 29th, 2018

    Last time we learned that the human heart functions as the greatest of all positive displacement pumps, moving a set quantity of blood through it at precise intervals during its operating cycle.   Today we’ll begin our exploration into how positive displacement pumps are used in industry, specifically within a food manufacturing plant.

    At one point in my career I was employed as a design engineer in a food manufacturing plant.   The plant was owned by the leading manufacturer of bakery products in the United States, responsible for supplying restaurants, bakeries, and grocery stores with finished and partially finished pastry goods that they would then resell.   The plant produced vast amounts of puff pastry dough products, all of which were formed and filled with various fillings while zipping along on a production line conveyor belt.   One of the products was a fruit filled pastry in which the belt moved so quickly, depositing fruit fillings into the dough by hand would be impossible, resulting in a frenzied mess similar to what Lucy encountered when she worked in a candy factory.

    Clearly, an automated machine would work better in this and other scenarios.   We’ll see how one known as a depositor functions on a food pastry line next time.

Copyright 2018 – Philip J. O’Keefe, PE

Engineering Expert Witness Blog

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Master of All Pumps, the Human Heart

Monday, May 21st, 2018

    We couldn’t do without pumps. They serve up water from the tap, circulate our car’s coolant, and the master of all pumps, the human heart, keeps us alive.   Pumps are essential in countless areas of our lives, and they’re of two major types, positive displacement or centrifugal.   We’ll start our discussion with a focus on positive displacement pumps.   Our hearts belong to this category.

Master of All Pumps, the Human Heart

Master of All Pumps, the Human Heart

As their name implies, positive displacement pumps displace, that is to say they move or circulate, a set quantity of liquid with each operating cycle.   Your heart moves 2 to 3 ounces of blood with every heartbeat and up to 2,000 gallons of blood per day!

Next week we’ll introduce an industrial application for a positive displacement pump when we install one in a food manufacturing plant.   You didn’t think those jelly pastries filled themselves, did you?

Copyright 2018 – Philip J. O’Keefe, PE

Engineering Expert Witness Blog

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Determining Patent Eligibility – Part 7, Process

Sunday, May 26th, 2013

      We’ve been discussing hurtles which must be jumped in order for an inventor’s creation to be considered for a patent.   Federal statutes, namely 35 USC § 101, define the bases of patentability, including providing definitions on key terms, such as what constitutes a machine, an article of manufacture, and a composition of matter.   Today we’ll wrap up our discussion on determining patent eligibility when we explore the final hurtle by defining process.

      To get an understanding of what is meant by process, we must look to the lawsuit of Gottschalk v. Benson, a case involving patentability of a mathematical algorithm within a computer program.   In this case the US Supreme Court held that a process is a series of steps or operations that transform substances or came about by way of a newly invented machine.

      Based on the Court’s definition, a process can be many things, from a production line that transforms corn into corn chips within a food manufacturing plant to a mathematical algorithm running within software on the platform of a newly devised type of computer.   However, the term usually pertains to a series of operations or steps, most frequently manufacturing in nature, where physical substances are transformed into useful products, that is, they possess the quality of utility, as discussed earlier in this blog series.   A “physical substance” is anything of a physical nature existing on our planet.

 

Engineering Expert Witness Patent Infringement

 

      Before I end this series I’d like to mention that under 35 USC § 101 an invention can be eligible for a patent if it makes a useful and beneficial improvement to an existing machine, article of manufacture, composition of matter, or process.   That is to say, something may have already been patented which performs a specific function, but if that is improved upon in any significant way, it may receive a new patent.

      For example, suppose an improved process for manufacturing food products was developed by adding additional steps to an existing patented process.   If this improvement results in benefits such as lowered production costs, increased production rate, or reduced health risks to consumers, then this improved process may be eligible for a patent under 35 USC § 101.

      Next time we’ll begin an exploration of the growing presence of 3D animations within the courtroom, specifically how they bring static 2D patent drawings to life.

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Determining Patent Eligibility – Part 5, Manufactured Articles

Monday, May 6th, 2013

      Imagine having freshly baked pastries available to you all day long, every day, while at work.   I’m not talking about someone bringing in a box of donuts to share, I’m talking about baked goods on a massive scale.   This is what I experienced in one of my design engineering positions within the food industry.   These baked goods constituted the articles of manufacture of the food plant, and they presented a constant temptation to me.

engineering expert witness food manufacturing

      Just what constitutes an article of manufacture is another aspect of the second hurtle which must be passed to determine patent eligibility.   It is addressed under federal statutes governing the same, 35 USC § 101, and is contained within the same area as the discussion of what constitutes a machine, a subject we took up previously in this series.

      Why bother defining articles of manufacture?   Well, while hearing the patent case of Diamond v. Chakrabarty regarding genetically engineered bacterium capable of eating crude oil, the US Supreme Court saw fit to define the term so as to resolve a conflict between the inventor and the patent office as to whether a living organism could be patented.

      The net result was the Court declared that in order to be deemed a patentable article of manufacture the object must be produced from either raw or man-made materials by either hand labor or machinery and must take on “new forms, qualities, properties, or combinations” that would not naturally occur without human intervention.   In other words, a creation process must take place and something which did not previously exist must be caused to exist.

      The court’s definition of articles of manufacture encompasses an incredible array of products, much too vast to enumerate here.   Suffice it to say that the defining characteristic is that if it should consist of two or more parts, there is no interaction between the parts, otherwise it could be categorized as a machine.   In other words, the relationship between their parts is static, unmoving.   An example would be a hammer.   It’s made up of two parts, a steel head and wooden handle.   These parts are firmly attached to one another, so they act as one.

      Next time we’ll continue our discussion on the second hurtle presented by 35 USC § 101, where we’ll discuss what is meant by composition of matter.
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Food Manufacturing Challenges – HACCP Design Principle No. 6

Sunday, November 20th, 2011
     My daughter’s boy friend stayed for dinner recently and was impressed with our after-dinner cleanup.  He watched as each of us carried out our individual assigned tasks, my wife putting away leftovers and condiments, my daughter rinsing and stacking plates into the dishwasher, and me at the sink hand washing.  To him we seemed a model of efficiency.  It didn’t take long to return the kitchen to its usual state of pristine evening cleanliness.  “Our kitchen is always a mess,” he complained, “probably because we’re so disorganized.”

     You can imagine what would happen if a food manufacturing plant operated like a disorganized household kitchen.  Although employees may know they are responsible for delivering safe products to consumers, without the right procedures in place an unsafe chaotic mess may result.  To get everyone moving in the right direction we look to guidelines established in HACCP Design Principle No. 6.

     Principle 6:  Establish procedures for ensuring the HACCP system is working as intended. –   In large part this Principle acts as a report card.  It follows up on the guidelines established in Principles l through 5, organizing activities into written procedures. 

     For example, design engineers must routinely analyze important identified stages within a design project, then write procedures, that is, a step-by-step instruction guide, which encompasses them.  In this way personnel involved in the design process make best use of the safeguards put in place by HACCP Design Principles 1 through 5.  These steps include things like preparing design proposals, analyzing risks and hazards, creating preliminary designs, conducting design reviews, building prototype equipment and tooling, running tests, collecting test data, and analyzing test results.  For each step, responsibilities of key individuals involved must be clearly defined and sequentially ordered.

     But writing department procedures is only part of Principle 6.  Procedures are no good if they’re just thrown into a file cabinet and no one ever looks at them.  What good are guidelines without a full understanding of how to use them?  Training may be necessary, and management must decide what form that educational process takes to be most effective.   

     Engineering management must verify that established procedures are adequate to the task.  This typically involves taking a hard look at finished design projects and checking critical factors.  Was an adequate risk analysis performed?  Were sufficient critical control points established and critical limits monitored for effectiveness? 

     Next time we’ll wrap up our discussion on HACCP Design Principles by examining No. 7.  It’s the last of the Principles and it’s concerned with establishing record keeping procedures.

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Food Manufacturing Challenges – HACCP Design Principle No. 4

Sunday, November 6th, 2011
     Imagine going on a diet and not having a scale to check your progress, or going to the doctor and not having your temperature taken.  Feedback is important in our daily lives, and industry benefits by it, too.

      Generally speaking, feedback, or monitoring, is a tool that provides relevant information on a timely basis as to whether things are working as they were intended to.   It’s an indispensable tool within the food manufacturing industry.  Without it, entire plants could be erected exposing workers to injury and consumers to bacteria-laden products.  It’s just plain common sense to monitor activities all along the way, starting with the design process.  Now let’s see how monitoring is applied in HACCP Design Principle No. 4.

     Principle 4:  Establish critical control point monitoring requirements. – Monitoring activities are necessary to ensure that the critical limits established at each critical control point (CCP) established under Principle 3 discussed last week are working as intended.  In other words, if the engineer identifies significant risks in the design of a piece of food processing equipment and establishes critical limits at CCPs to eliminate the risk, then the CCPs must be monitored to see if the risk has actually been eliminated.

     Monitoring can and should be performed in food manufacturing plants by a variety of personnel, including design engineers, the manager of the engineering department, production line workers, maintenance workers, and quality control inspectors.  For example, engineering department procedures in a food manufacturing plant should require the engineering manager to monitor CCPs established by the staff during the design of food processing equipment and production lines.  Monitoring would include reviewing the design engineer’s plans, checking things like assumptions made concerning processes, calculations, material selections, and proposed physical dimensions.

     In short, monitoring should be a part of nearly every process, starting with the review of design documents, mechanical and electrical drawings, validation test data for machine prototypes, and technical specifications for mechanical and electrical components.  This monitoring would be conducted by the engineering manager during all phases of the design process and before the finished equipment is turned over to the production department to start production. 

     To illustrate, suppose the engineering manager is reviewing the logic in a programmable controller for a cooker on a production line.  She discovers a problem with the lower critical limits established by her engineer at a CCP in the design of a cooker temperature control loop.  You see, the time and temperature in the logic is sufficient to thoroughly cook smaller cuts of meat in most of the products that will be made on the line, however the larger cuts will be undercooked.  The time and temperature settings within the logic are insufficient to account for the difference.  

     This situation illustrates the fact that monitoring does no good unless feedback is provided with immediacy.  In our example, the design engineer who first established the CCP and the critical limits was not informed in a timely manner of the difference in cooking times that different size meats would require, resulting in the writing of erroneous software logic.  Fortunately, continued monitoring by the engineering manager caught the error, leading her to provide feedback about it to the design engineer, who can then make the necessary corrections to the software.

     Next week we’ll see what design engineers do with the feedback they’ve received, as seen through the eyes of HACCP Principle 5, covering the establishment of corrective actions. 
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Food Manufacturing Challenges – HACCP Design Principle No. 1

Sunday, October 16th, 2011
     Imagine a doctor not washing his hands in between baby deliveries.  Unbelievable but true, this was a widespread practice up until last century when infections, followed by death of newborns, was an all-too common occurrence in hospitals across the United States.  It took an observant nurse to put two and two together after watching many physicians go from delivery room to delivery room, mother to mother, without washing their hands.  Once hand washing in between deliveries was made mandatory, the incidence of infection and death in newborns plummeted.

      Why wasn’t this simple and common sense solution instituted earlier?  Was it ignorance, negligence, laziness, or a combination thereof that kept doctors from washing up?  Whatever the root cause of this ridiculous oversight, it remains a fact of history.  Common sense was finally employed, and babies’ lives saved.

     The same common sense is at play in the development of the FDA’s Hazard Analysis Critical Control Point (HACCP) policy, which was developed to ensure the safe production of commercial food products.  Like the observant nurse who played watchdog to doctors’ poor hygiene practices and became the catalyst for improved hospital procedures set in place and remaining until today, HACCP policy results in a proactive strategy where hazards are identified, assessed, and then control measures developed to prevent, reduce, and eliminate potential hazards.

     In this article, we’ll begin to explore how engineers design food processing equipment and production lines in accordance with the seven HACCP principles.  You will note that here, once again, the execution of common sense can solve many problems.

     Principle 1:  Conduct a hazard analysis. – Those involved in designing food processing equipment and production lines must proactively analyze designs to identify potential food safety hazards.  If the hazard analysis reveals contaminants are likely to find their way into food products, then preventive measures are put in place in the form of design revisions.

     For example, suppose a food processing machine is designed and hazard analysis reveals that food can accumulate in areas where cleaning is difficult or impossible.  This accumulation will rot with time, and the bacteria-laden glop can fall onto uncontaminated food passing through production lines.

     As another example, a piece of metal tooling may have been designed with the intent to form food products into a certain shape, but hazard analysis reveals that the tooling is too fragile and cannot withstand the repeated forces imposed on it by the mass production process.  There is a strong likelihood that small metal parts can break off and enter the food on the line.

     Next time we’ll move on to HACCP Principle 2 and see how design engineers control problems identified during the hazard analysis performed pursuant to Principle 1.

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Food Manufacturing Challenges – Cleanliness

Monday, October 3rd, 2011
     My wife and I have an agreement concerning the kitchen.  She cooks, I clean.  Plates and utensils are easy enough to deal with, especially when you have a dishwasher.  Pots and pans are a little more challenging.  But what I hate the most are the food processors, mixers, blenders, slicers and dicers.  They’re designed to make food preparation easier and less time consuming, but they sure don’t make the clean up any easier!  Quite frankly, I suspect the time involved to clean them exceeds the time saved in food preparation.

     Food processors on a larger scale are also used to manufacture many food products in manufacturing facilities, and being larger and more complicated overall, they’re even more difficult to clean.  For example, I once designed a production line incorporating a dough mixer for one of the largest wholesale bakery product suppliers in the United States.  A small elevator was required to lift vast amounts of ingredients into a mixing bowl the size of a compact car.  Its mixing arms were so heavy, two people were required to lift them into position.  It was also my task to ensure that the equipment as designed was capable of being thoroughly cleaned in a timely and cost effective manner.

     Food processing machinery must be designed so that all areas coming into contact with ingredients can be readily accessed for cleaning.  And since most of the equipment you are dealing with in this setting is far too cumbersome to be portable, the majority of the cleaning must be cleaned in place, known in the industry as CIP.  To facilitate CIP, commercial machinery is designed with hatches and special covers that allow workers to get inside with their cleaning equipment.  Small, portable parts of the machine, such as pipes, cutting blades, forming mechanisms, and extrusion dies, are often made to be removable so that they can be carried over to an industrial sized sink for cleaning out of place, or COP.  These potable machine components are typically removable for COP without the use of any tools and are fitted with flip latches, spring clips, and thumb screws to facilitate the process.

     Everything in a food manufacturing facility, from production machinery to conveyor belts, is typically cleaned with hot, pressurized water.  The water is ejected from the nozzle end of a hose hooked up to a specially designed valve that mixes steam and cold water.  The result is scalding hot pressurized water that easily dislodges food residues.  Bacteria doesn’t stand a chance against this barrage.  The water, which is maintained at about 180°F, quickly sterilizes everything it makes contact with.  It also provides a chemical-free clean that won’t leave behind residues.  Once dislodged, debris is flushed out through strategically placed openings in the machine which then empty into nearby floor drains.

     As a consequence of the frequent cleanings commercial food preparation machinery requires, their parts must be able to withstand frequent exposure to high pressure water streams.  Parts are typically constructed of ultra high molecular weight (UHMW) food-grade plastics and metal alloys such as stainless steels, capable of withstanding the corrosive effects of water.  And since water and electricity make a dangerous combination, gaskets and seals on the equipment must be tight enough to protect against water making its way into motors and other electrical parts.

     Next time we’ll look at how design engineers of food manufacturing equipment use a systematic approach to minimize the possibility of food safety hazards, such as product contamination.

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