550 Gallon 20 Degree Cone Bottom Tank: Complete Buyer's Guide
The 550-gallon 20-degree cone bottom tank is a mid-size full-drain process vessel — 72 inches across and 47 inches tall, with a 20-degree cone steep enough to shed settling product cleanly. Rated to a 1.5 specific gravity, it's a versatile mixing and batch tank for chemical work that needs a more aggressive drain than a shallow cone provides.
Specifications at a Glance
Every figure below is pulled straight from the live product record for this exact tank — the same data on the product page, so what you read here and what you buy never disagree.
Standards & Materials
- ASTM D1998 — Standard Specification for Polyethylene Upright Storage Tanks. Governs wall-thickness and hydrostatic design for vertical rotomolded poly tanks of this class.
- FDA 21 CFR 177.1520 — Olefin polymers. The food-contact regulation the FDA-grade resin in this tank is compounded to meet.
- Specific gravity rating 1.5 — the tank is engineered for liquids up to 1.5× the density of water (water is about 8.34 lb/gal). Confirm your fluid’s SG before storage.
Product Overview
Five hundred fifty gallons is a practical batch size — large enough to be productive, small enough to handle and clean easily — and the 20-degree cone is the middle-ground angle. Steeper than a 15-degree cone, it sheds slurries, settling solids, and somewhat viscous products more reliably down to the apex; shallower than a 30-degree, it keeps the tank's overall height manageable. That balance makes the 550-gallon 20-degree a go-to for general process and chemical mixing.
Norwesco rotomolds it as a single seamless piece of virgin linear polyethylene rated to a 1.5 specific gravity, handling process liquids up to 12.5 pounds per gallon. As a mixing vessel the seamless construction pays off: nothing for an agitator to abrade, no crevice to trap product between batches. The 72-inch diameter gives a workable surface for a top-entry mixer, and at 47 inches the tank body itself is compact.
The cone tank rule is absolute here as everywhere: with no flat base, the tank must be carried in a stand rated for the full loaded weight, cradling the sidewall and transferring load through the legs — the apex is never to bear weight. Empty, the tank weighs 129 pounds; filled with a 1.5-SG product it carries roughly 7,010 pounds, all of which a properly rated stand must support. This particular listing is the tank alone — you'll need to provide a compatible stand.
The bottom outlet is a 2-inch NPT fitting at the apex, factory-installed and leak-tested for complete gravity drainage. The 16-inch lid serves filling, venting, mixer mounting, and inspection, and the translucent natural-white wall lets you watch the level and mixing. Maximum service temperature is 120°F. Norwesco's 3-year warranty applies, and the tank ships LTL freight — allow a couple of weeks, with liftgate available.
Technical Drawing
Official Norwesco technical drawing — 550 Gallon 20 Degree Cone Bottom Tank
Key Features and Specifications
- 550-gallon capacity — sized for full-drain mixing and batch processing
- Constructed from virgin linear polyethylene (HDPE) with 1.5 specific gravity rating — handles liquids up to 12.5 lbs/gal
- 47" tall x 72" diameter — compact vertical footprint
- 129 lbs empty, approximately 7,010 lbs when full at rated specific gravity
- 2" NPT outlet fitting — factory installed and leak-tested
- 16" lid opening for fill, venting, and interior access
- FDA approved for potable water and food-grade liquid contact
- 3 Year Warranty from Norwesco against manufacturing defects
- Translucent white walls allow visual level monitoring without opening the tank and reflect sunlight to keep contents cooler
- Rated for continuous service up to 120 F / 48 C
- Seamless one-piece rotational molding — no seams, no welds, no leak points
- Manufactured by Norwesco — a leading name in rotomolded polyethylene tanks
- Must be installed on the manufacturer-supplied or compatible stand rated for the full loaded weight. Never rest a cone bottom tank directly on its apex
- Ships via LTL freight — allow 2-3 weeks for delivery. Lift gate and residential delivery available at additional cost
Installation and Setup Guide
The 550-gallon installs around its stand like any cone tank, but at this manageable size the practical focus is matching the 20-degree cone's steeper drain to your process and getting the valve clearance right under a modest stand.
Stand and Foundation
Support the tank in a stand rated for the full loaded weight — roughly 7,010 pounds at 1.5 SG — that cradles the sidewall and carries the load through its legs to a level, load-bearing surface, preferably concrete. Use a stand designed for this tank; never improvise or rest the cone on its apex. The 20-degree cone is steeper, so the apex sits a bit lower for a given diameter — account for that when choosing stand height to leave room for your valve and discharge.
Placement and Connections
Plumb the 2-inch apex outlet with a full-port valve at the cone to keep the complete-drain advantage. The steeper 20-degree slope drains more aggressively, which is ideal for settling products — just make sure the discharge line below can accept the flow without backing up into the cone. Use flexible connections to absorb flex and mixer vibration, and match all wetted materials to the process chemical.
Venting and Mixing
Fit a vent in the 16-inch lid sized to your fastest fill or draw; the steeper cone can empty quickly, pulling vacuum if the tank can't breathe. If mounting a mixer, verify the impeller geometry suits the 47-inch tank height and the 20-degree cone so it sweeps the steeper cone effectively, and support the mixer on the stand or a bridge rather than the lid. Use a chemical-rated pressure/vacuum vent for off-gassing products.
Maintenance and Long-Term Care
At a manageable 550 gallons, this cone tank is easy to inspect and clean, but the chemical-service discipline is the same: watch the stand, keep the steeper drain clear, and clean thoroughly between batches.
Quarterly Inspection Checklist
- Stand: Inspect for corrosion, cracked welds, loose fasteners, or a settled leg, and confirm it's level for even drainage. The stand carries the entire seven-thousand-pound load — any weakening is the most serious finding.
- Cone and apex: Check the 20-degree cone and apex area for stress or distortion, and verify the tank is cradled with no weight on the apex.
- Outlet valve: Inspect the 2-inch apex fitting and valve for weeping or product buildup — the steeper cone helps keep this clear, but verify it.
- Vent and mixer: Confirm the vent is clear and the mixer mount secure.
Cleaning and Changeover
The 20-degree cone's steeper slope makes complete drainage especially effective for settling and semi-viscous products — open the apex valve and the batch, solids included, runs out cleanly. Between products, drain fully, then flush per the outgoing chemical's procedure, confirming through the 16-inch lid that the cone and outlet are clear. Verify polyethylene compatibility with the incoming chemistry, and manage rinsate per the label.
UV and Heat
If the tank is outdoors, inspect the wall yearly for chalking; many process cone tanks live indoors, where ventilation for off-gassing chemistry takes priority over UV. Stay within the 120°F service limit, particularly when mixing or reaction adds heat to the batch.
Alternatives and Comparisons
The 550-gallon 20-degree sits at a useful intersection of size and cone angle:
20-degree versus a 15-degree cone: the steeper 20-degree sheds settling solids and semi-viscous products more reliably, at the cost of a slightly lower apex and a bit more stand height. For thin, free-flowing liquids a 15-degree cone suffices and saves height; for products that settle or cling, the 20-degree is worth it.
Tank-only versus a tank-and-stand package: this listing is the tank by itself, so you'll source a compatible rated stand. If you'd rather buy a matched, ready-to-install package, a cone tank sold with its poly stand removes the guesswork of stand selection.
Other 550-Gallon Options
Frequently Asked Questions
How long will the 550 Gallon 20 Degree Cone Bottom Tank last?
Fifteen to twenty years is realistic with a properly rated, level stand and use within the 1.5-SG and 120°F limits. The stand is as important as the tank — an inadequate or unlevel stand is the main risk — while the seamless wall, free of seams to abrade under mixing, reaches the upper range when supported correctly.
What chemicals can I store in this tank?
Rated to a 1.5 specific gravity, it handles process chemicals, blends, slurries, and treatment solutions up to 12.5 pounds per gallon — the steeper 20-degree cone particularly suits settling products. Not for fuels, solvents, or flammables. Verify polyethylene compatibility against a chart for each chemical, since poly is attacked by certain hydrocarbons and strong oxidizers.
What kind of foundation does a 550-gallon tank need?
It requires a stand rated for the full loaded weight (roughly 7,010 pounds here) that cradles the tank and carries the load through its legs — never resting on the cone apex. The stand's legs sit on a level, load-bearing surface, ideally concrete. This listing is the tank only, so plan to provide a compatible rated stand.
Does this tank come with a warranty?
Yes — Norwesco's 3-year warranty covers factory material and workmanship defects. It excludes over-spec products, improper support (apex resting or an inadequate stand), incompatible-chemical attack, and impact damage. Document your rated stand and level setup for any claim.
Can I install this tank underground?
No — this is an above-ground process vessel that drains through a bottom cone while supported in a stand; it cannot be buried. For below-grade storage, use a purpose-built underground cistern engineered for soil load.
Buying Considerations
First decide on the stand: this listing is the tank alone, so you'll need a compatible stand rated for the full loaded weight before the tank is usable. Then confirm the 20-degree cone angle suits your product — choose it if you handle settling or semi-viscous chemistry, a 15-degree if your liquids are thin. Verify your process liquid is at or under 1.5 SG, and plan the bottom-valve clearance and overhead for any mixer. It ships LTL on a pallet — allow a couple of weeks and request a liftgate if you lack a dock or forklift.
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