Metering pump

An apparatus for pumping fluid at a substantially constant flow rate, wherein said apparatus is comprised of:

• (a) a first fluid transducer means for hydraulically coupling a hydraulic fluid to another fluid while preventing said hydraulic fluid from contacting said other fluid;
• (b) a second fluid transducer means for hydraulically coupling a hydraulic fluid to another fluid while preventing said hydraulic fluid from contacting said other fluid;
• (c) a third fluid transducer means for hydraulically coupling a hydraulic fluid to another fluid while preventing said hydraulic fluid from contacting said other fluid;
• (d) means for delivering said hydraulic fluid to said first fluid transducer means, said second fluid transducer means, and said third fluid transducer means so that the sum of the flow rates of said hydraulic fluid delivered to said first transducer means, said second transducer means, and said third transducer means is substantially constant;
• (e) timing means for continuously and sequentially repeating a timing cycle, wherein said timing cycle is comprised of the steps of:
• 1. withdrawing said hydraulic fluid from said first fluid transducer means while simultaneously delivering said hydraulic fluid to said second fluid transducer means while none of said hydraulic fluid is delivered to said third fluid transducer means;
• 2. thereafter, withdrawing said hydraulic fluid from said first fluid transducer means while simultaneously delivering said hydraulic fluid to said second fluid transducer means and simultaneously commencing delivery of said hydraulic fluid to said third fluid transducer means, wherein:
• (a) said hydraulic fluid is initially delivered to said third transducer means at a substantially zero flow rate which thereafter increases;
• (b) when said hydraulic fluid has been initially delivered to said third fluid transducer means, the flow rate of fluid delivered to said second fluid transducer means decreases;
• and
• (c) the total flow rate of fluid delivered to both said second fluid transducer means and said third fluid transducer means is substantially constant;
• 3. thereafter, withdrawing said hydraulic fluid from said first fluid transducer means while simultaneously commencing withdrawal of said hydraulic fluid from said second fluid transducer and simultaneously delivering said hydraulic fluid only to said third fluid transducer, wherein:
• (a) said hydraulic fluid is initially withdrawn from said second fluid transducer means at a substantially zero flow rate which thereafter increases;
• and
• (b) when said hydraulic fluid has been initially withdrawn from said second fluid transducer means, the flow rate of hydraulic fluid withdrawn from said first fluid transducer means decreases;
• 4. discontinuing the withdrawal of said hydraulic fluid from said first fluid transducer means and thereafter withdrawing said hydraulic fluid only from said second fluid transducer means while simultaneously delivering said hydraulic fluid only to said third transducer means;
• 5. withdrawing said hydraulic fluid from said second fluid transducer means while simultaneously delivering said hydraulic fluid to said third fluid transducer means while none of said hydraulic fluid is delivered to said first fluid transducer means;
• 6. thereafter, withdrawing said hydraulic fluid from said second fluid transducer means while simultaneously delivering said hydraulic fluid to said third fluid transducer means and simultaneously commencing delivery of said hydraulic fluid to said first fluid transducer means, wherein:
• (a) said hydraulic fluid is initially delivered to said first transducer means at a substantially zero flow rate which thereafter increases;
• (b) when said hydraulic fluid has been initially delivered to said first fluid transducer means, the flow rate of fluid delivered to said third fluid transducer means decreases;
• and
• (c) the total flow rate of fluid delivered to both said first fluid transducer means and said third fluid transducer means is substantially constant;
• 7. thereafter, withdrawing said hydraulic fluid from said second fluid transducer while simultaneously commencing withdrawal of said hydraulic fluid from said third fluid transducer and simultaneously delivering said hydraulic fluid, only to said first fluid transducer, wherein:
• (a) said hydraulic fluid is initially withdrawn from said third transducer means at a substantially zero flow rate which thereafter increases;
• and
• (b) when said hydraulic fluid has been initially withdrawn from said third fluid transducer means, the flow rate of hydraulic fluid withdrawn from said second fluid transducer means decreases;
• 8. discontinuing the withdrawal of said hydraulic fluid from said second fluid transducer means and thereafter withdrawing said hydraulic fluid only from said third fluid transducer means while simultaneously delivering said hydraulic fluid only to said first transducer means;
• 9. withdrawing said hydraulic fluid from said third fluid transducer means while simultaneously delivering said hydraulic fluid to said first fluid transducer means while none of said hydraulic fluid is delivered to said second fluid transducer means;
• 10. thereafter, withdrawing said hydraulic fluid from said third fluid transducer means while simultaneously delivering said hydraulic fluid to said first fluid transducer means and simultaneously commencing delivery of said hydraulic fluid to said second fluid transducer means, wherein:
• (a) said hydraulic fluid is initially delivered to said second transducer means at a substantially zero flow rate which thereafter increases;
• (b) when said hydraulic fluid has been initially delivered to said second fluid transducer means, the flow rate of fluid delivered to said first fluid transducer means decreases;
• and
• (c) the total flow rate of fluid delivered to both said first fluid transducer means and said second fluid transducer means is substantially constant;
• 11. thereafter, withdrawing said hydraulic fluid from said third fluid transducer while simultaneously commencing withdrawal of said hydraulic fluid from said first fluid transducer and simultaneously delivering said hydraulic fluid only to said second fluid transducer, wherein:
• (a) said hydraulic fluid is initially withdrawn from said first fluid transducer means at a substantially zero flow rate which thereafter increases;
• and
• (b) when said hydraulic fluid has been initially withdrawn from said first fluid transducer means, the flow rate of hydraulic fluid withdrawn from said third fluid transducer means decreases;
• 12. discontinuing the withdrawal of said hydraulic fluid from said third fluid transducer means and thereafter withdrawing said hydraulic fluid only from said first fluid transducer means while simultaneously delivering said hydraulic fluid only to said second transducer means;
• (f) means for synchronizing said timing means with said means for providing a substantially constant flow of hydraulic fluid;
• (g) means for allowing flow of said other fluid into said first fluid transducer, said second fluid transducer, and said third fluid transducer through a first conduit means;
• and
• (h) means for allowing flow of said other fluid out of said first fluid transducer, said second fluid transducer, and said third fluid transducer through a second conduit.