Worker behind importing quiet device for summoning porter? (4-4)

I believe the answer is:

beer-pump

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'device for summoning porter?' is the definition.
I can't tell whether this definition defines the answer.

'worker behind importing quiet' is the wordplay.
'worker' becomes 'bee' (a worker bee).
'behind' becomes 'rump' (informal term for the buttocks).
'importing' indicates putting letters inside.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'rump' enclosing 'p' is 'rpump'.
'bee'+'rpump'='BEER-PUMP'

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I've seen this clue in The Independent.

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