Snyder Industries 275 Gallon Open Top Dish Bottom Tank with Cover

The cover is the difference, and so is the bottom

Two things separate this tank from an ordinary open top, and both are on the sheet. The first is the cover: this part is named with one, where plenty of open tops are not, and a cover is the difference between a vessel you can leave a batch in overnight and one you cannot. It keeps dust, rain, insects and dropped tools out, it slows evaporation, and it turns an open hole at chest height into something a passer-by cannot fall into. It is not a seal and this page does not call it one; the sheet lists no gasket, no latch and no vent, and none is claimed. The second is the bottom. A flat-bottomed open top leaves a heel of product sitting on the floor of the vessel at the end of every batch, and somebody has to pump it, scoop it or tip it out. A sloped bottom does not: the contents run toward the low point and keep running, which is what you want when the vessel is emptied between batches, when a product settles, or when the same tank has to change duty and go out clean. That is the reason to buy this one rather than a straight-sided tank of similar volume, and it is also the reason it needs something under it. A tank with a dished or coned bottom cannot stand on its own bottom, and this sheet publishes no stand, no legs and no cradle. Settle that before the tank is ordered, not after it arrives, because the stand is what sets the working height, the clearance for a container under the drain, and the footprint you actually have to find room for. Size the batch and the turnover in the tank sizing calculator, take the freeboard from the tank sizing guide, and remember that an agitator in an open vessel wants more freeboard rather than less.

Two open tops with covers: 90 gallons and 275

The sheet gives this tank one sibling and it is a straightforward step down: SII-569TDVOT-45 holds 90 gallons in a 30 by 30 inch plan at 43 inches tall and 50 pounds, named on the sheet as a 15 degree vertical open top cone bottom tank with a cover. The two are the same idea at two sizes, and the choice is made on batch size and on reach. The 90 gallon vessel is small enough that one person can move it empty, low enough to work over comfortably, and cheap enough in floor space that a shop can keep two or three for different products. This one holds 275 gallons against 90, stands 58.5 inches against 43 and is listed at 85 pounds against 50, which puts the rim above a comfortable working height for most people once it is on a stand. That is the real trade: volume against the height you have to reach over and the structure you have to build under it. Where the same job could be done in two smaller batches, the 90 is often the better buy and we would rather say so. Where the batch is the batch and it has to be made in one vessel, this is the one. Both need a stand and neither sheet publishes one.

Need two of them? Request a written quote for the pair with freight to your ZIP, or call 866-418-1777 and we will price the truck once.

A 47 inch opening, an unsupported bottom and no published outlet

• The opening and the cover: the sheet gives 47 inches in its lid and manway field and names a cover on the product. It is a cover, not a seal: no gasket, no latch, no vent and no pressure or vacuum device is listed, and none is claimed. Lift it off to work, put it back to store, and do not treat it as a lid that will hold anything in.
• Because it is open under the cover, the vessel breathes as it fills and empties without any vent hardware, which is one fewer thing to get wrong. It also means the contents are exposed to the room whenever the cover is off, and to evaporation, dust and anything above the tank.
• Access for mixing and cleaning: 47 inches of opening is the argument for this shape. An agitator, a heater, a wand or a whole arm goes in without a fight, and the vessel can be washed out and inspected by eye rather than through a hole.
• Outlet and drain: the sheet publishes none. No outlet size, no bulkhead and no valve appears on it, so none is stated here. The sloped bottom is what makes the discharge worth specifying properly: the bulkhead size sets the drain time and, with solids in the product, decides whether the bottom empties or plugs. The bulkhead sizing and drain time article runs the arithmetic, and the high solids against low solids outlet sizing guide takes it further into particle size and bridge-free geometry.
• The stand: none on the sheet, no legs and no load rating. The bottom is not flat, so the vessel is carried by a structure that has to be specified, levelled and anchored before the first fill. Above it sits 2,294 pounds of water, and 3,440 pounds at the rating.

Whatever carries the tank has to bear on a flat, continuous, level surface itself: a finished floor or a poured pad, never rails with an unsupported middle. The concrete pad sizing guide covers how that slab is worked out for an above-ground polyethylene tank and where the boundary between the two frameworks sits.

Mixing, settling and drawing off the bottom

The duties are the ones that need a bottom that empties: batch mixing and make-up in plating, printing, coatings, food and beverage work; settling and decanting where solids have to be drawn off rather than stirred back in; slurry and suspension handling in small volumes; parts washing and quench duty; hatchery, aquaculture and live haul holding; and any bench or pilot process that changes product in the same vessel and has to leave it clean. The open top is what makes all of that practical to work with, and the cover is what makes it practical to leave. Where the vessel is doing plain water storage on a remote site with a fire reserve to hold, the fire-water reservoir design guide covers the sizing discipline and the cold-climate engineering an open vessel needs.

Fifty-nine inches shipped, 85 pounds, Arkansas

This tank is molded at Marked Tree, Arkansas and ships from Arkansas as the sheet says. The freight class is given as LTL, a mode rather than a numeric class, under NMFC 156600-02. Price the lane to your ZIP with the freight cost estimator; the listed price is before freight. At 85 pounds it is a two-person lift, taken under the body and never by the rim or the cover, and it must be set down on something flat: a tank with a sloped bottom parked on a concrete floor is standing on a point and will rock. Keep it on its pallet until the stand is built, levelled and anchored, then set it, fit the discharge, and water-fill it once while you read the bottom, the discharge joint and the floor beneath the stand. Take the cover off and look inside with a light before the first batch; it is the last moment the vessel will ever be that clean. Photograph the outlet fitting from below before the pipe goes on; a slow weep is easier to compare against than to describe.