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A fluid flow proportioning device including spool type valve elements (12,14,16) opposite end portions of which reciprocate in oppositely disposed and spaced apart valve block halves (100,102). So that the fluids being proportioned can never mix within the device despite the spool portions being dev

A fluid flow proportioning device including spool type valve elements (12,14,16) opposite end portions of which reciprocate in oppositely disposed and spaced apart valve block halves (100,102). So that the fluids being proportioned can never mix within the device despite the spool portions being devoid of sealing element within the cylindrical bores (13,15,17) in which they are slideable, central portions (21) of the valve elements are of smaller diameter than the diameters of the cylindrical bores (13,15,17) in which the valve elements are located, and resilient seals (105) encircle the portions (21) where they extend outwards from the valve block halves.

대표청구항 ▼

1. A fluid flow proportioning device including at least three spool type valve elements slidably located in respective cylindrical bores to which there is connected a common inlet passage for a first fluid flow under pressure, by way of respective inlet ports, a common inlet passage for a second flu

1. A fluid flow proportioning device including at least three spool type valve elements slidably located in respective cylindrical bores to which there is connected a common inlet passage for a first fluid flow under pressure, by way of respective inlet ports, a common inlet passage for a second fluid flow under pressure, by way of other respective inlet ports, respective outlet ports being spaced from the inlet ports and respective transfer ports being provided whereby, in response to sequential movements of the valve elements, one of a pair of pressure chambers at the opposite ends of each valve element is fed in turn with one of the two fluid flows under pressure admitted via one of the two transfer ports of the previously actuated element whilst a measured volume of the other fluid flow is discharged, by the movement of the respective valve element, from the other of the pair of pressure chambers via the other transfer port of the previously actuated element, the arrangement being such that as the valve elements are actuated in turn, the proportions of the two fluid flows being delivered for use are dependent on the number of pressure chambers for each fluid flow which are connected for use, the respective cylindrical bores in which the valve elements are slidably located being formed in oppositely disposed and spaced apart valve block halves, and central portions of the spool type valve elements being of relatively small diameter, that is to say smaller than the diameters of the cylindrical bores in which the spool type valve elememts are slidably located, and having resilient seals where they extend outwards from the valve block halves.