Technology Transfer, Development and Demonstration of an Oyster Grader Targeting Size (length) and Unit Specific to Grower’s Operations

Final Report
Jaillet Aquaculture Ltd
AIMAP 2012-G06

This project's primary objective was to source, purchase and test an oyster grading system for the New Brunswick oyster industry. The grading system was to include a washer, a singulating machine and a grader capable of sorting four sizes. The project was also conducted under the IRAP program 788102. The work was carried out by Atlantic Systems Manufacturing Ltd of Charlottetown, PE. The conclusion of this project: An oyster washer, singulator and grader designed to meet the needs of New Brunswick oyster growers and manufactured in Atlantic Canada. The direct result of this project is a technical advancement for Atlantic Canada's oyster industry and the local equipment manufacturing industry.

Introduction

The New Brunswick oyster industry is rapidly growing and requires mechanization to keep up to its expansion. The oyster growing operations are limited to further growth by the supply of labour in the area. The grading of oysters is a manual operation and thus is very labour intensive. An automated oyster grading system would decrease the time and labour required for grading and allow growers to expand their operations.

A number of companies manufacture oyster graders but are located in Europe and Australia. Most oyster graders are built for commercial scale operations with capacities beyond an oyster growers need. They are too large and their cost is not economically justifiable. This project's objective was to find a small oyster grading system that would meet the needs of a New Brunswick oyster grower and be cost effective. The machine will have to be adaptable to fit in smaller facilities, able to grade small to market oysters accurately, be user friendly and easy to maintain.

This report outlines the steps taken to find an acceptable oyster grader. The search was world wide but the final selection turned out to be a locally fabricated unit, custom manufactured to meet the growers requirements and within the budget of the project.

Phase #1 Technology adaptation and transfer

In August 2013 Donald Jaillet and Mike McKenna traveled to Australia to determine if an oyster grader manufactured by Oystek could grade New Brunswick oysters at an acceptable capacity and accuracy as required by the industry. The conclusion reached as a result of the trip was that the grader was not acceptable. The latest model was still in the prototype stage and not ready for the Australian industry let alone exporting to Canada. Another grader was investigated during the trip but it was a large commercial unit and did not meet the budget criteria and was physically too large a machine for most operations.

Phase #2 Plant layout and requirements for proposed oyster grading equipment

Mike McKenna traveled to Jaillet Aquaculture's facility in Bouctouche to obtain the building measurements, access existing utilities and determine connection locations. The building is a wood framed structure with aluminum outside cladding, shingled roof, insulated interior walls with painted plywood finish. The floor is smooth finished cement and is sloped to a central drain. Heating is by an oil fired forced air furnace. Lighting is ceiling mounted florescent fixtures. There are two overhead doors, 14' and a 10', a man door and three windows.

The electrical entrance is a 200 amp service 220 volt single phase located along the side wall. The water entrance is located below the electric and consists of a tank and pump. It is fed from a well that is shared with a residential building nearby. The conclusions of this phase were: The proposed oyster washer, singulation and grader equipment will fit in the Jaillet Aquaculture facility. The existing electrical supply will meet the equipment requirements. Since the equipment will need speed controllers which use three phase motors in order to do it economically, vari-frequency controllers that convert single phase power to three phase power will be required. The existing water service may not be adequate and will need to be determined after the oyster washer is running and washing results are examined. If the water supply is not adequate another water source will have to be found. The drain in the floor is not large enough to accept the discharge water from the washer and cannot deal with the silt. It is adequate for equipment wash down but the discharge water and silt from the washer will have to be piped out the side of the building into a small settling pool. 

Phase #3 Supply automated oyster grading machine

Once it was concluded that the Australian oyster graders did not meet the requirements for New Brunswick oyster growers, the search began for other potential oyster graders. Bain Blois from Blois Fish Processing Automation who represents a number of European companies that manufacture grading equipment was contacted. He emailed a quotation of a vision oyster grader manufactured by Marelec NV in Belgium. This machine had a greater capacity than what was required and an automatic singulation system was not available.

On August 30 during a conversation with Scott Linkletter of PEI Oyster Company, he mentioned that John MacKenzie, a PEI oyster grower from Baltic had built a vision oyster grader. John was contacted on September 4 and a meeting was scheduled at his oyster plant to see the machine operating. The initial observation was this was a grader that could meet the required objectives. John advised that his nephew Chris Pickering had designed the electronics and had a local welder build the conveyor. Chris works for a Frontier Power Systems, an electrical engineering company and designed the grader with assistance of his employer. Chris was contacted to discuss the grader and he suggested setting up a meeting with the company's owner, Carl Brothers. During the meeting on September 13, Carl stated he was interested in developing the oyster grader and wanted to partner with a manufacturing company to build more machines. On September 18 Donald Jaillet, Ronda Dillon, Florence Albert, Marcel Léger and Marie-Josée Maillet traveled from New Brunswick to meet with Chris Pickering, Carl Brothers and Mike McKenna. They visited John MacKenzie to see the oyster grader in operation.All were impressed with the design of the grader and felt it had the potential to meet the objectives of the project. Atlantic Systems Manufacturing Ltd (ASM) and Frontier Power Systems (FPS) agreed to put together a proposal on the supply of a grader incorporating requirements of the project's objectives and submit a quotation to Donald Jaillet.
On October 4, Frédéric Lhotellier from Adexia Inc, in Montreal who represented Hardouin Joel Sarl, an oyster equipment manufacturing company from France contacted Mike McKenna and wanted to meet to discuss the Canadian oyster industry and possible sales in the Atlantic area. Frédéric stated that the French company manufactured an oyster grader. He explained that Joel Hardouin was planning a visit to Canada and would like to meet on October 25. After the meeting with Frédéric and Joel, Hardouin Joel Sarl submitted a quotation on their oyster grading system but it also exceeded the capacity and budget of the project.

In the meantime ASM and FPS continued to work on their oyster grader proposal. On November 21, ASM submitted to Donald Jaillet, a quotation for an oyster grader and singulating system. Their proposed grader will use vision technology to determine an oyster's specific size and deposit it into the proper designated container while keeping count on the number of oysters graded. The operator will set the grade sizes and count required prior to feeding oysters to the machine. When the target number of oysters for a certain grade has been reached a light will signal that the count has been met. The grader design incorporates a camera, a computer and a central conveyor with four plow off paddles. The oysters are placed on the conveyor and pass under the vision camera that is connected to a computer which determines the oyster size according to preset values. The oysters travel down the belt and are removed from the belt by pneumatically operated paddles at the appropriate grade onto a chute that feeds the oyster container. The chute will have a pneumatically operated door to hold oysters after the count has been met and the container is being replaced. The operator will hit the switch once the empty container is in position, then the door will open and the accumulated oysters will empty into the container. This sequence will allow continual operation of the grader. A computer display will show oyster pictures as they pass under the camera and allow the operator to re-program for different oyster sizes. The grader camera will be activated when an oyster on the conveyor belt passes through a light beam which sends a signal to take a picture.

Some design features had to be incorporated into the grader. The conveyor belt cannot have any visible flaws or a mechanical splice so the belt must be made endless. The grader must be constructed so an endless belt can be installed easily. The conveyor section of the grader must be bolted and no air hoses or wire can impede installing the belt. Since the overall length of the grader must be kept to a minimum, there is only room for the four size discharge chutes. The grader must run continuously so a door was added to hold oysters in the chute after the count was reached and the operator was replacing the container. The grader also has to feed two types of containers; ship to shore tote boxes and oyster grow out bags. A drawer shelf supports the boxes and is moved in to allow a bag to sit on a formed angle, rest against the shelf and slide over the size chute. The software had to be developed to meet Donald's current requirements while allowing for future additions.

Jaillet Aquaculture accepted their proposal and ordered the equipment. On December 5 Donald traveled to Charlottetown, PE to sign a contract with ASM and met with Carl and Chris to further develop the criteria of the computer software. FPS began designing the grader's electronic components and ASM began the grader design. On December 14 Donald shipped oysters to ASM for design purposes and for FPS vision development. 

The construction of the grader began in January. On February 20 Donald and Ronda visited ASM to inspect the progress of equipment and discuss the project completion. On March 12 Donald, Ronda and Florence traveled to ASM and brought market oysters to test on the grader. Further tests and modifications were made in the following weeks. The oyster grader was completed on March 21, 2013. At the conclusion of this phase, an oyster grader designed and manufactured in Atlantic Canada has been produced that meets the requirements of the New Brunswick oyster growers.

The next step will be to run the grader at full production at Jaillet Aquaculture. Various size oysters must be tested to determine the minimum size oysters that can be graded and any modifications needed for these smaller oysters. These tests will be carried out this spring and summer in phase 7 of this project.

Phase #4 Supply automated oyster singulating system

The oysters must feed onto the grader one at a time at a fixed separation distance in order for the vision camera to take a picture of individual oysters and then place them in their appropriate size container. ASM began the design of the oyster singulating system in December 2012. Using the experience it had gained in the mussel industry for the singulation feed of X-ray grading equipment, a general concept was created. Tests were carried out on some existing mussel singulating equipment which highlighted problems. Unlike mussels, oysters are not uniform in shape, vary in size and their exterior shell surface is rough. These differences lead to flow, bridging and transfer difficulties. Modifying, testing and developing a new style of singulation led to the final design and manufacture of the system.

The oyster singulating system consists of an elevating conveyor, rotating tube singulator, and an accelerator conveyor. The oysters discharge from the oyster washer into the hopper of the elevating conveyor. The hopper is lined with a food grade rubber to cushion the oysters. The oyster are conveyed up and empty into a hopper that feeds the rotating tube singulator. This machine forms the oysters into a single file and empties them onto the accelerator belt one at a time. The accelerator conveyor separates the oysters and feeds them onto the grader belt which is traveling at a higher speed and further separates the oysters. All three pieces of the singuating system have vari-frequency controllers to allow the operator to change the speed independently to optimize oyster spacing.

The construction of the singulation equipment began in late January 2013 and the system was ready for testing with the grader and washer in early March. A few modifications were made and the result was a singulation system capable of feeding the oyster grader at the required rate for the grader. Tests were carried out only with market size oysters since smaller oysters are not available during the winter.At the conclusion of this phase, an oyster singulation system that meets the requirements of the new oyster grader was designed and manufactured in Atlantic Canada.

The next step will be to run the system to meet the grader capacity at full production at Jaillet Aquaculture. Also various size oysters must be tested to determine the minimum size oysters that can be singulated and any modifications needed for smaller oysters. These tests will be carried out this spring and summer in phase 7 of this project.

Phase #5 Development of an oyster washer for the grading line

When the oysters are harvested there is a coating of silt that must be removed prior to grading. Existing washers consist of a conveyor running through a wash tunnel with pipe header above and under the belt that spray water at the oysters. The dirt and water drain out the bottom of the washer and the oysters then go to a manual grading table. An oyster washer needed to be developed to integrate into the new oyster singulating and grading system.

ASM began design of the oyster washer in December 2012. First a search was carried out of existing washing methods for various food products with an emphasis on living products. The use of rotating or oscillating brushes commonly used for vegetables was examined but the operating cost of a series of brushes and potential damage or mortality of oysters ruled this method out. Using air to remove dirt proved futile. The best method remained a water spray system. Thus the design concept was to use the fundamental spray washer design but to add improvements to meet the requirements of the grading system.

On existing washers, oysters occasionally sit on top of each other as the travel through the wash tunnel with only the top of one oyster being washed and the bottom of the other being washed. A bar is sometimes placed over the belt to try and keep the oysters only one layer deep but they cause some damage, clog up and are difficult to adjust. ASM's solution was to use a rotating brush to keep the oyster single layered. The brush is driven by a shaft mounted gearmotor with a vari-frequency controller to change the rotational speed. The brush is mounted on an adjustable frame so changing the height setting is easily accomplished.

A persistent problem with oyster washers is the choice of the belt used to convey the oysters through the wash tunnel. The belt must be corrosive resistive, have openings to allow washing of the oysters through it and able to withstand the grit of the oyster shell and dirt. The standard washing belt is a stainless steel flat wire belt that has 1" x ½" openings and is ½" thick. This belt is rugged enough to handle the grit but its thickness limits the ability to wash the bottom of the oysters. Plastic modular belting has been used but wears out quickly with the grit. Mesh belts have been used but most are very expensive and wear out due to the grit.
A search for a suitable belt resulted in the discovery of a recently developed belt manufactured by Wire Belt Company of America. Their Compact Grid™ stainless steel wire belt met the washer requirements, plus it uses small diameter drive sprockets and was flexible enough to allow a small diameter back flex roller. These belt designs made it possible to turn the belt under itself and then back forward to form a small drop in the wash conveyor. This drop will cause the oysters to flip over thus allowing washing both sides of the oysters from the top. Using top and bottom sprays ensures the oysters are completely washed. The drop also helps remove some of the dirt. This concept was incorporated into the washer.

The water spray system was also examined. A typical washer has a series of pipes with holes or spray nozzles to wash the oysters as they pass though. The possible use of rotating spray arms was throughly investigated but the water pressure required to turn these arms is too high and could harm the oysters. The alternative was improving the existing spraying method. The spray headers were redesigned to maximize their cleaning ability with properly sized and positioned spray nozzles. A total of 10 pipes run across the wash tunnel (6 on top, 4 underneath). The top pipes consist of two headers of 3 pipes with the bottom pipes in headers of 2 pipes. A set of top headers and bottom headers are positioned opposing each other to form a wash section. There are two wash sections to accommodate for the belt drop midway through the wash tunnel. The belt bed support rails were positioned to allow maximum coverage of water spray trough the belt. Each header is attached to a valve to allow the operator to control the amount of water needed depending on the dirtiness of the oysters.

The spray nozzles can become plugged or damaged, so they may have to be cleaned or replaced. A hinged cover over the wash tunnel allows access to the upper header spray nozzles. The bottom headers can be removed for nozzle access. All the spray header pipes have threaded end caps to allow for draining and cleaning.

All the water from the washers is collected by sloped drip pans under the conveyor belt and flow to a central drain. This water could be filtered and reused if the oysters are not too dirty and water supply is limited. An opening near the idler end of the conveyor belt allows access of any dirt caught in the return side of the belt.

The oyster washer is to feed the incline conveyor of the singulation system. Since the capacity of the grader is fixed the washer must be able to supply oysters at the required rate. Also the grader works on the count of oysters and smaller size oysters will have a larger number per square foot of belt. Thus the washer must have the ability to vary its speed to meet the grader's capacity, so a vari-frequency speed controller is required.

The layout of the grading system at Jaillet Aquaculture requires the washer to feed the incline conveyor at 90E because of the building size. When the grading system is not in use the washer will sit across the building and limit use of the area. To solve this problem the washer was equipped with casters to allow the washer to be moved when not in use. The casters are fitted with locks and brakes to hold in place when required. The electric supply will have a twist lock plug to allow quick disconnect. The water and drain connections will also have quick disconnects.

The construction of the oyster washer began in late January 2013 and it was ready for testing with the singulation system and grader in early March. Since the oysters available were already cleaned only the conveying and feed to incline conveyor could be observed. The tests were carried out only with market size oysters since smaller oysters are not available during the winter. At the conclusion of this phase, an oyster washer that meets the requirements of the new oyster grader system was designed and manufactured in Atlantic Canada. The next step will be to run the washer at Jaillet Aquaculture and evaluate its cleaning ability. Also various size oysters must be tested to determine conveyor speeds, water requirements and any modifications needed for smaller oysters. These tests will be carried out this spring and summer in phase 7 of this project.

Phase #6 Installing, commissioning and personnel training of the grader equipment

On March 27 the washer, singulator system and grader were delivered to Jaillet Aquaculture in Bouctouche Bay and set up in their facility. ASM technicians installed the equipment in place and then familiarized personnel from Jaillet Aquaculture on the operation and maintenance of each item. Oysters were not available due to the time of year, so a small number of glued together test oysters were run over the equipment. At the conclusion of this phase, the oyster washer, singulation system and grader have been installed and commissioned at Jaillet Aquaculture in Bouctouche Bay NB. The personnel from Jaillet Aquaculture have been trained in the operation and maintenance of the equipment. The next step will be to run the equipment with oysters at Jaillet Aquaculture and resume the training of the Jaillet Aquaculture personnel. Technicians from ASM and FPS will return later in the year when oyster are available to complete the commissioning and personnel training. This will be carried out in the spring and summer in phase 7 of this project.

Conclusions & Recommendations

At this point in the project an oyster grading system that is capable of washing, singulating and grading oysters into four separate grades has been sourced, ordered, manufactured, tested and installed at Jaillet Aquaculture Ltd In Bouctouche Bay in New Brunswick. This grading system will allow oyster growing operations to expand by diverting their precious labour resources previously used on grading, to working on the water to increase their oyster holdings.

The oyster grading system was completed in the winter of 2013 when only a few market size oysters were available. The next phases of this project are to test the grading system this spring at its maximum capacity and to validate its accuracy in size and count with various size oysters. Modifications to the equipment and software may be required to improve the operation of the grading system and if so then be retested and evaluated.