McAlpine V33WM twin drain connector - what's inside?

I have a rather strange possible use for this (connecting two bilge pumps to a single outlet on a boat) and thus need to know a *little* bit about what's inside it.

In the description at

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it says 'an air break is incorporated within the connector", what does that mean exactly? In the installation description at

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it says there's an air-break and a non-return valve.

My major requirement is that water flowing into one of the two inlets won't tend to flow straight out of the other. As long as it's directed down the outlet that will be fine, it doesn't have to be totally isolated just not 'straight across'.

Any ideas anyone? Has anyone got one?

Basically all I need is a tee-piece with a divider down the 'leg' of the tee. The 'leg' will discharge direct into a long vertical pipe and the two bilge pumps will pump into two 'sides' of the tee piece. As long as the water can't go straight across all will be well, a little bit going across won't matter at all.