An 18 inch vented threaded manway lid from Snyder, in polypropylene
SII-34300012 is Snyder's 18 inch vented threaded tank manway: the screw-on lid that closes the main top opening of a tank and lets it breathe. It is moulded in polypropylene, weighs 3 lb, and ships in a package 18 by 18 by 3 inches. It is the part people order when the original lid has cracked, gone brittle in the sun, lost its vent, or simply gone missing, and the part a tank builder orders when fitting out a new opening.
Replacing a lid on an existing tank? Call 866-418-1777 with the tank's make and part number and we will confirm this is the right lid, or get freight to your ZIP and add it to your cart above.
What the vent does
Every time liquid is pumped into a tank, the same volume of air has to get out, and every time liquid is drawn off, air has to get in. A vented lid gives that air a path. Without one, a tank being filled fast pushes air out wherever it can, and a tank being drained fast pulls a vacuum that can draw the walls in. Temperature does the same thing more slowly: a tank in the sun breathes out during the day and in at night. A vented manway handles normal breathing for water and most stored liquids. If you fill or empty at a high rate, or the tank holds something that gives off fumes, talk to us about a dedicated vent as well, because the lid vent is not sized for every job.
The 18 inch opening is also the way into the tank. It is wide enough to look inside with a light, to drop in a float or level sensor, to get an arm and a brush in for cleaning, and on many tanks to fill from a hose without an extra fitting.
What to check before you buy
- The opening. Measure the threaded opening on the tank, not the old lid. This lid is 18 inch.
- The thread. Manway threads are not standard from one maker to the next. Give us the tank make and part number and we will confirm with Snyder that SII-34300012 matches before it ships.
- Vented or sealed. This is the vented version. If the tank must not breathe through its lid, ask us for a non-vented lid and a separate vent.
- The material. Polypropylene handles water, most fertilizers and many common chemicals. If the tank holds something aggressive, check it in our chemical compatibility guide.
Shipping and installing
At 3 lb in an 18 by 18 by 3 inch package it is a small shipment. The listed price is before freight; the freight cost estimator gives the cost to your ZIP. If you are ordering it with a tank, put both on the same order. To install, clean the threads on the tank opening, start the lid by hand so it does not cross-thread, and turn it down snug. Do not force it with a tool, and check that the vent is clear before the tank goes back into service.
Ready to order? Add it to your cart at the top of this page, get LTL freight to your ZIP, or call 866-418-1777. The listed price is before freight.
Freight
LTL freight is quoted to your ZIP with the freight cost estimator or by phone at 866-418-1777. The listed price is before freight.
See this tank
Product video. Watch the 18" Vented Threaded Tank Manway video (59 seconds) with dimensions, fittings and shipping notes.
Ready to order?
Add it to your cart at the top of this page, get LTL freight to your ZIP, or call 866-418-1777. The listed price is before freight.
