Family-owned and operated since 1978, Sundre Contracting Co. understands the importance of delivering a quality product. The operation, located in Sundre, Alberta, Canada, produces more than 30 different product sizes—from 1/16-inch (1.6-mm) fine sand to 12-inch (305-mm) screened rock and everything in between. Whether its customer is an Alberta road builder, concrete plant or any of a number of golf courses in Alberta, British Columbia and Saskatchewan, its products must meet tight specifications or be rejected. Dealing with severe screen media blinding and pegging from clay material and a rainy climate, Sundre needed an advanced solution. After exploring several screen media options, the operation found one that helped eliminate the production-crippling effects of these conditions, ultimately saving them thousands while waiting for Mother Nature to cooperate.
One instance of Sundre’s success with this advanced screen media is evident in a challenging road job it accepted. Using two 6-foot x 20-foot (2-m x 6-m) ELRUS screen decks equipped with conventional woven wire screen media, the operation needed to screen the 3/4-inch (20-mm) minus aggregate from the customer’s own highly clay-contaminated pit. With the addition of rain every second day, the operation was quickly losing quality because screen media throughput was being compromised. In addition, production time was significantly reduced due to the need to frequently shut down and clean the screens.
“The wet, sticky nature of the material was causing severe blinding and pegging of the woven wire on our first screen deck,” stated Jason Harder, Manager of Operations at Sundre Contracting. “In order to meet customer material spec, we needed to dry the material, which took time away from producing new, profitable material.”
It was impossible to effectively screen while it was raining because it only added to the stickiness of the material, so Harder knew they needed another solution. The operation tried a variety of woven wire and self-cleaning screen media options, but all were still experiencing severe blinding and pegging. At the recommendation of Matt Armstrong, dealer representative at ELRUS Aggregate Systems, Harder installed Major Wire 7/8-inch (22-mm) Flex-Mat® 3 Series D Tensioned screen media and saw dramatic results.
“The operation went from not being able to produce at all in marginally rainy weather to being able to operate through heavy downpours,” commented Armstrong. “We’ve recommended Major Wire’s Flex-Mat 3 screen media before and knew it could stand up to the challenge of screening sticky, clay-ridden material.”
Major Wire’s Flex-Mat 3 self-cleaning screen media allows producers to increase open area, create more screening action and eliminate blinding and pegging problems to achieve more throughput of spec material. Its distinctive lime-green polyurethane strips bond individual wires, allowing them to vibrate independently at different frequencies.
An increase in screening action was just what the Sundre operation needed. More properly sized material fell through instead of sticking to the wire, increasing production by 100 percent on rainy days since the operation no longer needed to shut down and clean the screens. Using Flex-Mat 3 Tensioned screen media, Sundre screens between 250 and 300 TPH, depending on the product it is making. That is a savings of nearly 2,000 to 2,400 tons per day that the operation would be losing to rain delays. Harder estimates that using Flex-Mat 3 during this particularly rainy month saved the operation at least 100 hours of production time previously lost due to the need to shut down and clean the screens.
A Versatile Screening Solution
Sundre uses Flex-Mat 3 screen media on at least five of its six screen decks in a variety of positions, depending on the material being screened. The operation also utilizes several Flex-Mat 3 wire configurations and opening sizes—from 3/16 inch (5 mm) to 7/8 inch (22 mm)—to properly screen the wide range of products it offers customers. For example, the operation uses 7/16-inch (11-mm) Flex-Mat 3 Series D Tensioned screen media in its McCloskey mobile vibratory screener to prescreen various sand products. The Series D configuration provides Sundre with precise sizing of passing material so it can produce the spec material needed by various customers. To screen larger aggregate material, Sundre uses 3/8-inch (10-mm) stainless steel Flex-Mat 3 Series LFM Tensioned screen media.
“We love the versatility of Flex-Mat 3,” stated Harder. “We make more than 30 different products in our operation, from golf course sand, to concrete and road base aggregates and decorative stone. Flex-Mat 3 helps us screen and wash all products more efficiently and saves us thousands in lost production each year. In addition, we estimate that its increase in open area provides us with up to 30 percent more screening capacity than before.”
Flex-Mat 3 screen media has also helped Sundre cut costs in other areas. For example, previously, when screening its coarser products, such as 3/4-inch (20-mm) minus aggregate material, the operation was using a wash plant to screen off the sand that was causing blinding and pegging issues in the dry screening process. This required a large volume of water usage. Flex-Mat 3’s vibrating wire technology has virtually eliminated this blinding and pegging problem—which means most of the sand does not need to be sent through the wash plant, helping Sundre reduce its annual water usage. While the wash plant deck is still used to clean many different products, this has immensely reduced the quantity of silt heading to their settling pond. Before, it was necessary to clean and drain the settling pond many times a season. Now that Flex-Mat 3 has reduced the amount of silt in the product when it reaches the wash plant, they are able to spend more valuable time screening instead of cleaning.
“We’ve not seen any type of screen media work better than this,” says Harder. “Major Wire seems to have this technology wrapped up and it will remain a staple in our operation.
Install It Right The First Time
Sundre Contracting solved its screening challenges using Flex-Mat 3 Tensioned screen media, but noted that—no matter what brand you choose— if screen media is not installed properly, it will slow down an operation and hurt product quality, production and profit.
“Matt Armstrong came out to our plant the first time we ordered Flex-Mat 3 from ELRUS,” said Harder. “He helped us install the new screen media correctly so we could get the best results possible, and showed our team how to do the same, so when our next order arrived we would know what to do.”
The two most common types of tensioned screen media are Flex-Mat-type and woven wire. Here are some installation tips Major Wire and Matt Armstrong recommend for each:
Prior To Installation:
Check for proper tensioning system and correct installation of tension bar
Ensure that crown bar is fully engaged in “U” channel rubber and is consistent in height
Ensure clamp rails are not worn thin, bent or deformed
Ensure clamp rails are the same length as the screen media
In bolt-type tensioning systems:
Check the rail design and height of bolt holes
Check for missing bolts (replace if broken or missing)
Clean the rail and hook edge thoroughly
Check for cracks, broken welds and loose bolts on screen box or deck (fix if necessary)
Ensure clamp rails are not overlapping multiple panels, but fit each panel
Side-tension systems: Ensure there is a .750 inch space between the wall and the outside of the hooks
Align polyurethane strips perfectly on all crown bar supports, making sure they lie flat on the bars when tightened
If equipped with overlaps, place overlaps on top of preceding screen media starting at the discharge end
Stretch Flex-Mat-type screen media “tight as a drum”
Do not over-tighten when using an impact wrench on wire diameters less than .148 inches
Check tension: the heavy end of a screwdriver or hammer should bounce easily on the screen media
Before You Install:
Look for significant damage to crown bars and screen decks
Inspect the crown bar rubber for damage and wear (replace if necessary)
Ensure the crown bar rubber is the same type and height and covers all of the crown rails
Make sure side clamp rails are not worn thin, bent or have curves or “dimples” where the clamp rail bolts come through
Ensure the side clamp rails equal the length of the screen media or they will cause uneven tensioning
Check crown bar height by doing the string test
Remove all material build-up from the hook ledge on the pan side of the screen box and/or the crown bar rubber
For Proper Installation:
Make sure the screen media has the correct outside and inside hook width for the deck
Ensure that the ends of the screen media panels fit together tightly to prevent the passing of oversize material
Make sure the lengths of all screen media “tail ends” don’t exceed more than 50% of the opening size where they meet
Side-tension screen boxes: position the screen media so clearance from the pan side to the hook is even on both sides
Tension your screen media by tightening the bolts intermittently from both sides
Once installed, make sure all screen media is seated properly on all crown bar tops and the side clamp rails match the length of the screen mediaConduct Frequent Inspections
Once you have properly installed your screen media, conduct daily inspections before startup and after shutdown. Make sure that your screen media and screen boxes are free of unnecessary wear, breakage or damage. Catching problems ahead of time can save thousands in costly fixes later.