Muth Pumps Patented FARR Plunger

The Pinnacle of Artificial Lift Design and Performance

The FARR Plungers unique patented design allows it to pump when sand and other solids are present in the production fluid, without sticking. It is the obvious solution to maximize your pumps life while minimizing risks to personnel, environment, and budget.


  • 3-6x longer pump life
  • Patented design prevents sand erosion
  • Available in all standard pump sizes
  • Fits any API pump barrel
  • Can operate at depths of 15k ft. and deeper
  • Tapered leading edge catches loose sand
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Engineering Superiority

We’ve Been Here Since the Beginning, It’s Tried & Trued

A longer lifespan is just the beginning. 50+ years of industry experience has allowed us to push performance engineering to a new benchmark. The FARR Plunger outperforms, outruns, and flat out saves you valuable time and hard earned profit.

200%Increased Run Time

60%Reduction in Well Pulls

875kYearly Savings

Initial Field Study

Kern County

Midway-Sunset Oil Field

FARR plungers put to the test

The 33 FARR plungers installed in these 31 wells have run a total of 6,125 days as of January 23, 2001 for an average run time of 186 days. Most of these original FARR plungers are still in operation. This average run time will increase as these plungers continue to operate. (Later follow up showed the FARR Plunger averaged nearly 3 times the run life.)

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In-Depth Case Study

Coalinga, CA

Analysis of Coalinga FARR Plunger Data

The purpose of the Study
  • Analyze FARR Plunger performance based on data from the Coalinga field to compare the performance of the FARR plunger to other plungers used in the same wells.
  • Based on field observations, the FARR was suspected to provide longer runtimes on average and require fewer well pulls than other plungers used in the same wells.
  • Determine if the observations could be supported by quantitative analysis, and if so, see how much longer FARR runtimes were on average.
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Sand Facts

An Exploration of Different Sand Scenarios in the Field

Most down hole experts think, just because a well goes down and there was sand found in the pump, that the well sanded up. That is not true. There is a big difference between sand sticking the plunger in the pump barrel and the well actually sanding up. The difference is: if a small amount of sand is found in the pump, chances are it was just enough to stick the plunger in the pump barrel causing the well to go down. If there are several joints of tubing above the pump full of sand, then you have actually sanded up.

Down hole plungers with normal fits (-.002 to -.004) will stick in the pump barrel when very little sand is present, with the exception of the FARR plunger. Historically, the answer to stuck plungers is to loosen up the fit of the plunger (-.010 to -.015) to where the sand will fit between the plunger and the pump barrel without sticking. This gives the pump very poor pump efficiency (70% to 80%) right off the bat. Plus, this will introduce abrasive materials (sand) between the two metal surfaces which will further damage the pump. This gives the pump a very short pump life and causes the well to be pulled more often than necessary. This is a very costly solution to handling solids.

The FARR plunger is a revolutionary new design for down hole pumps which will allow the pump to pump tremendous amounts of sand without sticking, maintaining pump efficiency (97% to 99%) and generally giving the pump 3 to 5 times the life expectancy of a pump with a conventional pump plunger.

However, the FARR plunger will sand up (not stick) eventually if you do not have the velocity or viscosity of the produced fluid to carry the sand all the way to the surface. What happens is, the FARR plunger will pump the sand up into the tubing and the sand will reach a state of limbo to where the sand is settling out of solution (gravity pull) at the same rate as the produced fluid is pushing it up. Eventually you will pack so much sand up into the tubing that it will impede the performance of the rods to go up and down, causing the well to shut down. Then the sand will settle out of solution and fall on top of the pump, generally several joints of tubing full of sand. This is a true sanding up situation.

Most producers (oil companies) say they understand and that sanding up is bad news. However the good news is the overall life of the pump is so much longer. 3 to 5 well pulling jobs were avoided by the FARR plunger not sticking.

In conclusion, with FARR plungers in your pumps, you will receive the following benefits: far longer pump life (no pun intended), higher pump efficiency, less down time, more production, fewer well pulling, fewer pump repairs, thus higher profits.

Settling and Lifting Velocities

Determine the sand grain size(s) in millimeters of the sand, which is found in your problem well(s). Check chart "A" below to determine the settling velocity of that particular sand grain size. Check chart "B1" for the size of rods and tubing in your problem well(s). Then move to the right under the production rate associated with the problem well(s). Determine the upward (lifting) velocity associated with that rod, tubing & production combination. If the upward velocity does not exceed the settling velocity for that grain size, then the sand is accumulating in the tubing and not being produced to the surface. This will cause rod and tubing wear, wells to sand up and pulling wells wet (striping job). Now check chart "B2". Find the upward velocity that exceeds the settling velocity for the sand grain size(s) at the production rate of the well(s). Move to the left to determine the tubing size needed to produce the sand to the surface for a given production rate.

Chart A:

Settling Velocity of different size sand grains in water.

Grain Sizes (mm)   Settling Velocity (ft./sec.)
1mm = 0.3281 ft./sec.
2mm = 0.6562 ft./sec.
3mm = 0.9843 ft./sec.
4mm = 1.3124 ft./sec.
5mm = 1.6405 ft./sec.
Chart B:

Upward velocity of different size tubing's at different production rates.

Tubing Size - Rod Size = 250 bls./day 500 bls./day 750 bls./day
2-3/8" - 7/8" = .672 ft./sec. 1.345 ft./sec. 2.018 ft./sec.
2-3/8" - 3/4" = .648 ft./sec. 1.296 ft./sec. 1.944 ft./sec.
2-7/8" - 1" = .601 ft./sec. 1.202 ft./sec. 1.803 ft./sec.
2-7/8" - 7/8" = .573 ft./sec. 1.146 ft./sec. 1.719 ft./sec.
2-7/8" - 3/4" = .552 ft./sec. 1.104 ft./sec. 1.656 ft./sec.
3-1/2" - 1-1/8" = .387 ft./sec. .774 ft./sec. 1.161 ft./sec.
3-1/2" - 1" = .374 ft./sec. .748 ft./sec. 1.122 ft./sec.
3-1/2" - 7/8" = .364 ft./sec. .728 ft./sec. 1.092 ft./sec.

Production tubing (side string) without rods at different production rates. (ft./sec.) Dual string pumping system.

Tubing Size = 250 bls./day 500 bls./day 750 bls./day
1-1/4" = 1.564 ft./sec. 3.280 ft./sec. 4.692 ft./sec.
1-1/2" = 1.149 ft./sec. 2.298 ft./sec. 3.447 ft./sec.
2" = 1.068 ft./sec. 2.136 ft./sec. 3.204 ft./sec.

Satisfied Customers

“A while ago Spindletop had 2 wells they could not get the rig off of before they would sand up. The Hynes #25 had a ring plunger, we converted it to a FARR Plunger and she’s still pumping!! The Hynes #19 had a PA plunger, we converted it to a FARR Plunger and she’s also still pumping! Metal plungers DID NOT WORK in these wells either. The FARR Plunger kicked !@# in this case.”

Ricky Huey - CDI - Freer Texas

“ Green Country Supply, Inc. in Ratliff City, Oklahoma has a great appreciation and respect for the FARR Plunger. The FARR Plunger has solved the pump problems we have had with flow restriction caused by sand. We have run 12 plungers in the last year without any failures. No sticking of plungers. No grooving of plungers. No packing off of traveling valve due to sand. The unique funnel design of the plunger’s top, allows the sand to fall into the plunger away from the barrel I.D. The FARR Plunger has proved itself in the Pilfield of South Central Oklahoma. These wells are approximately 6,500’ deep. These wells make a lot of gas, give up a lot of sand and are pumped very hard! The pumping unit stroke lengths run from 86” stoke to 168” stroke. The FARR Plunger has performed well in these tough conditions. I, Jamie Griffin would recommend the FARR Plunger to anyone having sand problems down hole.”

Jamie Griffin - Pump Shop Manager - Green Country Supply, Inc.

“To Garold,

The following is a testimonial from Sutton Pump & Supply, Inc. for you to include on your website, etc.

After experiencing sticking problems with conventional plungers in Pennsylvania coal bed methane fields, we switched to the FARR Plunger. We noticed immediate results with moving solids (coal fines) and few stuck pumps followed by longer runs and less expensive repairs.


Kyle A. Williams - President - Sutton Pump & Supply, Inc.