Floating suction data sheet: the tank details we need to quote

A floating suction unit is made for one tank. The same product in a tall, narrow tank and a wide, low one needs a different arm layout, and the float has to be sized for the lightest product the tank will ever hold. A short list of tank and product details lets us design the unit correctly the first time.

Download the Vens floating suction enquiry data sheet (PDF), fill in what you know and send it with your tank drawing. The Vens floating suction units datasheet (PDF) describes the full range.

At a glance

• Tank geometry decides the layout: single arm, double arm, roller type or riser.

• Product properties decide float size, materials and seals.

• Outlet details decide the swivel joint and how the unit is installed.

• Options such as a position indicator and sample lines are chosen to suit how the tank is operated.

What we ask for, and why

Detail	Why it matters
Inside diameter and shell height	The arm swings in a vertical plane from the outlet. Whether one straight arm can reach the top level depends on how wide the tank is compared with how high it is filled.
Maximum filling level and lowest operating level	Set the arm travel, where the float rests at low level and the stops that stop the arm going past vertical.
Roof type and roof leg heights	Units under an external or internal floating roof need rollers, and a track under aluminium decks. The roof at its lowest position must clear the float.
Outlet nozzle size, height, orientation and projection	The swivel joint bolts to this nozzle. Its height and direction set the start of the arm.
Manhole size	In existing tanks every part has to pass through the manhole.
Product, specific gravity range and temperature	The float is sized for the lightest product so the inlet stays submerged; seals and metals are chosen for the product and temperature.
Internal obstructions	Roof columns, heating coils, mixers and ladders must stay clear of the arm through its whole swing.
Bottom shape, slope and lining	These decide the rest supports and the protective pads under the float and arm.
Flow rate	Sets the pipe and inlet size so the inlet does not draw air or disturb the surface.

Options to decide early

• Position indicator: a cable from the arm to a weighted pointer outside the shell shows from the ground that the unit is moving with the level. It is strongly advised under floating roofs.

• Check cable: lets operators raise the arm to confirm it is free.

• Sample lines: draw samples from set heights in the tank.

• Foot valve: keeps a riser pipe full in underground and horizontal tanks.

• Materials: carbon steel, stainless steel or aluminium. Jet fuel service has its own rules, covered in our aviation fuel floating suction unit page.

What you get back

A proposed layout showing the unit in your tank, the materials and options, and a quotation. Where a client specification or standard applies, tell us which one and we design to it.

See the full range: single arm, double arm, floating roof tanks, horizontal and underground tanks and the swivel joints they run on.

Vens floating suction units are designed by engineers who studied at MIT, Stanford, Cornell, the Indian Institutes of Technology, Arizona State University and the University of Cincinnati, and who have worked in the refineries, depots and power plants that use them. They size each unit for the tank, the product and the duty, choose materials and seals for the product, and design to proper factors of safety.

Questions

Can a floating suction be fitted to an existing tank?

Usually yes. The unit bolts to the existing outlet nozzle and is assembled inside through the manhole. Rest supports may need fixing to the floor, and normal tank entry and gas-free rules apply.

What if I do not know the specific gravity range?

Tell us every product the tank may store. We size the float for the lightest of them.

Do you need a drawing?

A tank general arrangement drawing with the nozzle orientation answers most of the questions on the sheet. Photos help for replacements.

Ready to send your tank details? Send us your details or e-mail the completed data sheet to venshydro@gmail.com, and we will come back with a proposed layout.