Circulating pump for high pressure and high temperature applications
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Circulating pump for high pressure and high temperature applications

A high pressure high-temperature magnetic circulating pump is described. The design is based on the concept of contactless bidirectional pumping action. This pump can deliver a continuous flow at temperatures up to 175 °C and pressures up to 2000 bars. Wetted parts are fabricated from stainless steels, there are no elastomeric seals or lubricants required, and the pump can be physically mobile during operation. Tests with toluene at ambient temperature and pressure showed that volumetric flow rates of up to 320 cm3 min−1 and pressure heads of up to 2.2 bars could be achieved.
Magnetically coupled reciprocating pumps have long been recognized as the best option for liquid and/or gas circulation in closed-loop high pressure systems. A number of interesting and innovative designs have appeared over the years, each aiming to overcome a particular challenge or limitations of previous designs. The pump described here was designed and fabricated as a part of a project involving physical-property measurements on synthetic hydrocarbon mixtures. The mixtures resembled petroleum-reservoir fluids and were tested under varying conditions of temperature and pressure, up to 175 °C and 1400 bars. The pump was used both for periodic circulation of the mixtures inside a test loop to promote mixing and to permit testing of physical property sensors under conditions of controlled flow. Other than being rated for the aforementioned temperature and pressure conditions, the pump was also required to deliver a continuous and reasonably smooth flow, to be mobile within the testing environment during operation, and to be easy to run and maintain. Mobility was required because, in use, the pump was attached to a plate that was rocked back and forth to energize an agitator device installed in another piece of high pressure equipment. A review of the published circulating pump designs revealed that none fulfilled all of these requirements.
The greatest limitation for most of the previous designs is that they deliver fluid in only one stroke direction, resulting in a highly intermittent flow.  Only a few published designs offer continuous pumping.  Many also utilize an electric motor for the pump drive. Since electric motors are not usually compatible with the desired maximum operating temperature, this approach would require the motor to be placed outside the tempera