How to Check a Sweco Vibratory Separator Before You Accept Delivery: A 6-Step Checklist

I'm the person who has to sign off on every piece of separation equipment that comes through our facility. If it's a Sweco vibratory separator, a replacement screen deck, or a set of finishing machine components, it goes across my bench before it goes into production. I've been doing this for about 14 years, and I review roughly 200 unique items a year. Last year, I rejected about 6% of the first submittals—not because anything was broken, but because the documentation didn't match the machine.

This checklist is for anyone who's about to receive a vibratory separator, new or used, and needs to know what to look for before the freight company leaves. There are six steps. It'll take about an hour if you're methodical, maybe less if you're not. Don't skip the last one.

Step 1: Read the Nameplate Like It's a Contract

Start with the nameplate, not the paint job. The nameplate tells you the model, serial number, build date, motor horsepower, voltage, phase, frequency, and maximum RPM. If any of that doesn't match the purchase order, stop. Not "check later." Stop.

I made the classic rookie mistake in my first year: I assumed "standard" meant the same thing to every vendor. A motor spec that was "standard" for us turned out to be a 60 Hz motor on a 50 Hz machine. Cost me a $600 redo and a late shipment.

Here's the thing about company names, too. Sweco's equipment brand has its own history, and older project files can reference names like Grontmij Sweco on the engineering side. That's a different business from the one that builds separators, but it's still a good reminder to verify who actually issued the drawing. On the equipment side, I've seen import documents with "RBM Sweco Productions" on them, and the actual manufacturer stamp inside the frame was different. It might be perfectly legitimate, but it's not something you want to discover after you've paid.

• Model and serial number on the order match the plate.
• Motor data (HP/kW, voltage, phase, Hz) matches your site power.
• Design code or revision number is shown, not just a trademark.
• Country of origin matches the certificate of origin, if required.

Step 2: Measure the Screen, Don't Just Look at It

The most common failure I see is a screen deck that looks right but isn't. A "60 mesh" screen from one supplier can be a completely different opening from another supplier if the wire diameter is different. You need to measure it.

Take a magnifying glass and a pocket scale, or an optical comparator if you have one. Count the openings over a known distance. Measure the wire diameter. Compare that to the drawing or the part number. The tolerance is normally around ±0.0002 inch on the wire, and the mesh count should be within ±1 count over 1 inch. If it's off, the separation cut point changes—maybe by a lot.

A customer in Lincoln, Nebraska, called me about a replacement deck that was wearing out in about 400 hours instead of the 800-hour life they'd been getting. The screen looked identical in photos. When I measured it, the wire was one gauge lighter. The supplier saved about $11 in material and caused five weeks of extra downtime. That's the kind of difference you can't see until it's too late.

If you're buying a used separator, ask for the original screen spec and verify it before the machine is loaded on the truck.

Step 3: Check the Welds and the Frame—Before It's Painted

If the machine is already painted, you're at a disadvantage. It's much easier to inspect a bare frame. If you can get to the shop before paint, do it.

I look for three things:

• Weld continuity around the screen box and support members.
• No pitting or porosity in welds that hold the vibratory assembly.
• Proper radius at stress points. Sharp corners are cracks waiting to happen.

On a round separator, the most important weld is the one that holds the upper and lower frame sections together, if it's a two-piece design. A poor weld will show up as a fatigue crack after a few thousand hours. That's not a cosmetic issue.

I have mixed feelings about used equipment, for what it's worth. On one hand, I've seen 20-year-old Sweco units that still run beautifully. On the other, I've seen "refurbished" machines that were just painted and relabeled. You can't tell the difference from a photo. You need a mechanic's report, or better yet, inspect the machine yourself.

Step 4: Run It Dry Before It Goes In

This is the step that gets skipped the most because it requires power. If the machine is in a warehouse, that's your problem to solve. Make the power available. I say this because I skipped it once myself.

I knew I should have gotten a written test record for a separator we bought in 2022, but I thought, "What are the odds? It's a new machine, it's basically the same as the last one." The odds caught up with me: the unit vibrated at the wrong amplitude because the counterweights were set for a different screen weight. It didn't fail the no-load run, but it shook the discharge chute to pieces on day one. That was a $1,200 mistake, and it was on me.

What to do during a dry run:

• Listen for rubbing, scraping, or uneven bearing noise.
• Measure vibration amplitude at each side. It should be within 10% side to side.
• Check the direction of rotation against the arrow on the machine.
• Let it run for at least 30 minutes, then feel the motor and bearing housing temperatures. If you can't keep your hand on them for 5 seconds, that's a problem.

Should mention: we always check rotation direction before bolting anything down. It's easier than switching leads later.

Step 5: Confirm the Drawings Match Your Existing Installation

A separator can be perfectly built and still be wrong for your site. I've seen this more times than I'd like to admit.

Get the GA drawing—the general arrangement drawing—and compare it to your actual floor space, chute positions, and bolt holes. Check the discharge spout orientation. Check the overall height with the base and spring mounts. Check the distance from the center of gravity to any nearby wall or column.

My biggest regret in this area: not verifying the center distance before a machine was placed. The separator fit in the bay, but the discharge spout didn't line up with the collection chute. We had to build an adapter, which took a week and cost about $3,500. On paper, the "cheaper" unit was $2,000 less than the alternative. By the time we added the adapter, it was $1,500 more.

If you're buying a separator with a screen deck that's supposed to be a drop-in replacement for an older unit—especially one built around the millennium—do not trust the part number alone. Part numbers get reused in other industries, and "compatible" doesn't mean "identical." Measure the old screen frame. Compare the dimensions with a tape measure if you have to.

Step 6: Read the Documentation Before You Sign

This is the last step, but it's the one I'd never skip. The paperwork is part of the product.

What I need to see:

• Operation and maintenance manual with the serial number printed on it.
• Certificate of conformance, or declaration of conformity if CE/UKCA applies.
• As-built GA drawing with a revision stamp.
• Test report from the final run, including vibration amplitude and bearing temperatures.
• Spare parts list with part numbers and quantities.
• Warranty terms in writing, including what happens if a component fails in the first year.

If the supplier can't provide the as-built drawing, that's a red flag. It suggests they don't actually know what they sent you. I also want the warranty terms in the English language version of the contract, not just a verbal promise from the salesperson.

I still kick myself for not documenting a vendor's verbal promise on response times a few years ago. They said they'd be there within 48 hours if we had a breakdown. When we had one, it took five days. I had nothing in writing, so I couldn't hold them to it. That's on me.

What I'd Tell You Before You Compare Quotes

Here's where I sound like the grouchy quality guy: the cheapest quote is not the cheapest machine.

In my experience managing 40+ acceptance inspections, the lowest quote has cost us more in roughly 60% of cases. Not because the machine was defective every time, but because of the time we spent fixing the small things: wrong documentation, a missing certificate, a chute that didn't line up, a screen that was one gauge off.

That $200 saving turned into a $1,500 problem when the "standard" mesh we were promised turned out to be off. The $4,000 savings on a used separator turned into $8,000 of rework when the bearing housing was worn. I don't mean to insult people who care about price—I understand why price matters. But I would rather pay a little more for a supplier who sends the right drawings and answers the phone when something doesn't look right.

If you're the one who skipped the dry run because you were in a hurry, trust me, I've been that person. It's a $1,200 mistake I don't want you to make.