The rod pump is connected to sucker rod after being assemblied on the surface then it is pulled down to the well bottom through the tubing. Thus it is convenient for the inspection and workover because they can be pulled up and down through the tubing and suitable for deeper well. The life span of tubing can be prolonged for decreasing the times of the thread of the tubing being turned on and off and the time of the workover. The rod pump can be classified into two types of mechanical seating and cup seating. Also it is divided into three types as RHA (stationary heavy well barrel top anchor rod pump), RHB (stationary heavy well barrel bottom anchor rod pump) and RHT (travelling heavy well barrel bottom anchor rod pump).
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| Model | Nominal Dia. mm(in) | Plunger Length m(ft) | Stroke m | Pump Constant m3/d | In Sucker Rod |
| 20-125TH | 32(1.25) | 1.2-1.8 (4-6) |
0.6-7.3 | 1.14 | ¾ |
| 25-125TH | 32(1.25) | 0.6-7.3 | 1.14 | ¾ | |
| 20-150TH | 38(1.50) | 0.6-7.3 | 1.64 | ¾ | |
| 25-150TH | 38(1.50) | 0.6-7.3 | 1.64 | ¾ | |
| 20-175TH | 44(1.75) | 0.6-7.3 | 2.24 | ¾ | |
| 25-175TH | 44(1.75) | 0.6-7.3 | 2.24 | ¾ | |
| 25-225TH | 57(2.25) | 0.6-7.3 | 3.69 | ¾ | |
| 30-275TH | 70(2.75) | 0.6-7.3 | 5.50 | ? | |
| 35-325TH | 83(3.25) | 0.6-7.3 | 7.70 | ? | |
| 40-375TH | 95(3.75) | 0.6-7.3 | 10.26 | 1 |
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Main parts process and material:
Pump barrel: plain carbon steel plating (A1), ordinary carbon steel carbonitriding (B1), ordinary carbon steel carburizing (B2), low alloy steel nitride (B5).
Barrels shall be additionally inspected, with a frequency of 100 %, according to the following:
Barrel inside surface finish shall be visually inspected on all barrels per manufacturer’s specifications.
The inside diameter sealing surface of barrels shall be inspected with appropriate equipment, and in such a manner, that assures the specified tolerances are maintained through the entire length of the barrel.
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Plunger: 1045 steel spraying (B1), 1045 steel spraying (B2), 1045 steel chrome plating (A1), 1045 steel double chrome plating (A2).
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Valve ball and seat: stainless steel (A1), cobalt chromium (B2), tungsten carbide (C1), nickel and carbon compounds (C2), titanium carbide (C3).
Ball and seat assemblies shall be additionally inspected, with a frequency of 100 %, according to the following:
All ball and seat assemblies shall be vacuum tested, with dry sealing surfaces, at 19 in. (483 mm) Hg minimum vacuum with no leakage for a minimum of
3 seconds after vacuum source is isolated. Ball shall be randomly rotated in the seat during the test.
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Other accessories: