Section 7. Liability for advance payments, collusive mortgages and incumbrances

Any payment by the owner, contractor or subcontractor upon
  a contract for the improvement of real property, made prior to the  time
  when,  by  the  terms of the contract, such payment becomes due, for the
  purpose of avoiding the provisions of  this  article,  shall  be  of  no
  effect  as  against the lien of a subcontractor, laborer, or materialman
  under such contract, created before such payment actually becomes due. A
  conveyance, mortgage, lien or incumbrance  made  by  an  owner  of  real
  property,  for  the  purpose of avoiding the provisions of this article,
  with the knowledge or privity of the person to whom  the  conveyance  is
  made  or  in  whose  favor the mortgage, lien or incumbrance is created,
  shall be void and of no effect as against a  claim  on  account  of  the
  improvement of such real property, existing at the time of the making of
  the conveyance or the creation of such mortgage, lien or incumbrance.
    Nothing in this chapter shall subject the title of a purchaser of real
  property for value whose conveyance is recorded prior to the filing of a
  lien  pursuant to this chapter to any such lien, provided the instrument
  of conveyance contains the provisions mentioned in subdivision  five  of
  section thirteen.