• FMD small volume provers save space with a smaller overall footprint, not only does this allow other use of valuable real estate, but it provides more flexibility for prover placement and overall system design considerations.

Uncertainty:

• The American Petroleum Institute (API) requires a 0.02% uncertainty for custody transfer applications. Both FMD compact provers and ball/pipe provers can meet this requirement under most flow conditions. However, ball/pipe provers typically have an uncertainty of 0.01% to 0.02%, which can increase at high and low temperatures. A small difference in uncertainty can equate to significant gains and losses in custody transfer applications, especially over large flow volumes. FMD small volume provers have an uncertainty of 0.009% to 0.004%, which is significantly lower than ball/pipe provers. FMD provers provide a lower uncertainty allowing for more confidence in your measurement results.

Cost / Expenses:

• The cost of a Flow MD Small Volume Prover (SVP) is generally less expensive than that of a ball/pipe prover. The size and flow range capabilities of the prover dictate the cost. SVPs generally have flow capabilities from 100 to 24,500 gpm and ball provers range from 250 to 35,000 gpm. Pricing on all prover types varies by manufacturer and complexity.

• • Installation:
    • In addition to the initial purchase costs, to effectively compare the two prover types, installation costs and maintenance costs over the life of the prover need to be factored in as well. A Flow MD small volume prover (SVP) is less expensive to install than a ball prover from two perspectives. First, an FMD small volume provers take up very little real estate compared to a ball prover. Second, very little construction or site preparation is needed prior to installing an FMD Prover, which reduces overall installation costs.
    • Maintenance:
      • Serviceability Cost / Time: The SVP replaces the 4-way valve, ball, and launch chamber with a smooth retraction piston drive system using externally mounted optical detector switches and has internal piston seals and external piston shaft seals that are conveniently replaced in hours. With the conventional pipe/ball prover, even the slightest service issue can sometimes take a day or even a week to resolve depending on the size of the prover. Additionally, the prover must be drained prior to servicing which increases the service down time due to the larger amount of process fluid.
      • Self-Diagnostic Controller: The newer SVPs are equipped with controllers that monitor the system and allow for real-time visual knowledge of the condition of the proving operation. The controller also helps with system diagnostics capability and service notifications. This is option is not available for older model conventional pipe/ball provers.
      • Water Draw – Prover Calibration: Because of the smaller displaced volumes, the FMD Small Volume Prover can either be gravimetrically or volumetrically water drawn. This is not possible for a conventional pipe/ball prover in the dimensional sizes necessary to prove large bore meters. The water draw process for FMD SVPs can be completed quickly either offsite or onsite using a certified mobile water draw laboratory as opposed to the pipe/ball water draw process. (API Chapter 4, Section 9, and calculations per API Chapter 12, Section 2). The water draw process for larger pipe/ball prover requires the use of a SVP to confirm the master meter which is then used to verify the prover. Also, there are the large amounts of water and the disposal of that water that needs to be taken into consideration.

Fluid Compatibility:

• Both small volume provers (SVPs) and ball provers provide accurate measurement on most liquid hydrocarbon products. However, SVPs have more overall compatibility with a range of products and provide more flexibility when changing product runs. This is because ball provers use spheres which can have compatibility issues with different hydrocarbon liquid products. Balls may have to be changed out prior to switching product runs. This can cause additional downtime and maintenance issues over the long-term life of the ball prover.

  Flow MD SVPs are a great option for applications where compatibility with a wide range of products is important. Flow MD SVPs are compatible with most hydrocarbon liquid products, including crude oil, refined products, NGLs, and hot bitumen. Flow MD SVPs are also easy to change over between products, which can save time and money in the long run.

Meter Compatibility:

• Both ball provers and FMD Small Volume Provers (SVPs) can be used with most meter types. However, some older ball provers may need to be retrofitted to work with Coriolis and ultrasonic meters.

  Retrofitting can involve adding lengths of pipe to the prover, which can increase its footprint. SVPs and recently built ball provers both use pulse interpolation methodologies for proving of manufactured pulse meters.

Speed of Proving:

• FMD small volume meter provers utilize a smaller volume, in many cases, 80-90% less volume, which correlates directly to the speed of proving operations. FMD provers can be up to 80% faster than older proving technologies.

Field Service Needs – Prover Water Draw

• SVP systems Since SVP provers utilize less volume and occupy a smaller footprint, most field water draw operations can be completed in 1 to day.

In summary, FMDs Small Volume Meter Provers offer a reliable cost-effective solution for verification of all meter types in comparison to conventional, ball, or pipe proving technology.

Contact us to learn more about replacing your conventional provers.