| 摘要 |
<p>This invention relates to pumps. It is well established that the ease or difficulty of pumping materials or admixes of materials is directly related to the viscosity and/or the flow characteristics of the material or mixture, it being generally accepted that the higher the viscosity and/or the lower the flow characteristics the more difficult does it become to pump the material. The object of the invention is to provide an effective pump (1) for such materials which objective is met by a construction comprising a cylinder (2), a piston (3) within the cylinder (2), an inlet (5) to the cylinder part-way along its length, said inlet (5) being opened and closed by reciprocation of the piston (3) within the cylinder (2), an outlet (6) from the cylinder (2) and valve means (7) at the outlet (6) from the cylinder (2) that is open during a drive stroke and closed during a return stroke of the piston (3).</p> |
