PP Liquid Surface Cover Ball · Technical Reference & Specifications

1. How a Floating Cover Layer Works

A liquid surface cover ball is a polypropylene ball placed on the free surface of an open tank, basin or reservoir. The balls float and pack into a continuous layer, so the liquid that was exposed to air is covered by a layer of plastic instead.

Three losses scale with exposed surface area: evaporation of the liquid itself, heat carried away with the vapour, and the mist and fume released from the surface. Covering the surface attacks all three at the same point. The cover does not seal the tank and it is not a lid — it reduces the free surface to the small gaps between balls, while still allowing the liquid to be sampled, pumped or agitated.

The cover also moves with the liquid. Because the balls are only loosely packed, they part around anything entering the surface and close up again afterwards, which is why the technique is used on tanks that are operated rather than stored.

2. Ball Forms

(1) Hollow ball with rim

A hollow polypropylene sphere with a flat rim moulded around its equator. The sealed air inside the shell provides the buoyancy, and the rim lets neighbouring balls sit closely against each other in the layer. Because the body is hollow, the weight added to the tank surface stays low, which matters when a large open area has to be covered.

(2) Foamed ball

A solid polypropylene foam body, also supplied with a rim. There is no internal cavity, so a ball that is damaged does not take on liquid and sink, and the solid body is not punctured by the normal handling it sees in a working tank.

Choosing between them

Both forms are used for the same duty — evaporation, heat loss and mist control on open liquid surfaces. The right choice depends on the liquid, working temperature and how much surface movement the tank sees, so tell us the duty and we will confirm the form and size rather than assume one.

3. Specification Fields

Item	Value
Product	PP liquid surface cover ball (floating cover ball)
Material	Polypropylene (PP)
Standard ball size	Φ40 mm
Other ball sizes	On request — confirm the diameter your duty calls for
Ball forms	Hollow ball with rim; foamed ball
Service temperature	On request
Density / specific gravity	On request
Coverage per m²	On request — depends on ball diameter and layer thickness
Packing	On request — confirm bag, carton or bulk, and export marking
MOQ / price	On request — confirm size, quantity & destination

Fields marked On request are confirmed for the specific ball you order. They are not estimated here, and no performance figure is quoted without a confirmed basis.

4. Applications

• Pickling and acid pickling lines — covering the acid surface to reduce acid mist above the tank and cut acid consumption.
• Electroplating and anodising tanks — limiting evaporation and fume release from heated process baths.
• Chemical storage and dosing tanks — holding in the liquid where the tank stands open for long periods.
• Open clear-water reservoirs and storage basins — reducing evaporation loss and keeping heat in the stored water.
• Water and wastewater equalisation basins — covering large open areas where evaporation and surface emission matter.
• Aeration basins and open channels — where the surface is exposed but agitation is moderate.

Where a tank is violently agitated or has a high continuous overflow, part of the cover will be pushed aside; tell us the flow conditions and we will confirm whether a cover ball layer is the right approach.

5. Installation and Maintenance

1. Deploy — pour the balls onto the liquid surface from the tank edge or from a light mesh basket. No frame, anchor or tank modification is required, and no lifting equipment is needed for normal quantities.
2. Cover the whole free surface — in most duties the aim is a single complete layer across the open area. Exposed area is what drives the losses, so a complete layer matters more than adding a second layer on top of a partial one.
3. Watch the edges and inlets — the cover parts where liquid enters, where a pump suction sits close to the surface, or where there is an overflow weir. Allow for extra balls in these zones.
4. Top up as needed — balls can be carried off at an overflow, blown by strong crosswind on outdoor basins, or lost during tank cleaning. Keep a small stock of spares; the layer is restored by adding balls, not by rebuilding it.
5. Keep them out of pump suctions — fit the usual suction screen or guard where a pump draws from a covered tank, as you would for any floating material.

6. Ordering Notes

To quote on request, send us:

• Tank or basin dimensions, and the open area to be covered
• The liquid and its working temperature
• The problem you are solving — evaporation, heat loss, mist or fume release, or a combination
• Whether the surface is still, agitated, or has a continuous overflow
• Quantity required and the receiving port

Prices, minimum order quantities and export packing are quoted against those details. Φ40 mm is the standard ball size; other diameters and both ball forms are confirmed per order.

Compiled from our own product records and standard practice for floating cover layers. No textbook figure or third-party test result is reproduced for this product, and no parameter is carried over from a different ball type.