Downhole Pump Fittings

  • The standard parts of the sucker rod pump produced by our company are well-selected, precision-made, stable in quality and excellent in performance, .
  • exported to the United States, Europe, Asia and Asia,
  • and we establishes cooperative relationships with international customers such as Shell, GE, Schlumberger, and JOHN CRANE.

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Downhole Pump Fittings Manufacturers and Suppliers

Pump Barrels

Sanjack’s pump barrel can be up to 146mm in diameter with various materials such as low carbon steel, SS, Brass.

Pump Plungers

Pump plungers are made from cold-drawn, seamless-steel tubing, which is machined to size and spray-metal coated.

Valve Ball & Seat

Sanjack ball-and-seat valves are made to meet or exceed the international standard Specification.

Valve Rods

Valve rod materials include steel, alloy steel, stainless steel and brass.

Pump Barrels
  • Maximum diameter 146mm.
  • low carbon steel, SS, Brass.
Pump Plungers
  • Spray welding
  • Chrome plated
Valve Ball & Seat
  • Vacuum tested
  • Meet or exceed the international standard Specification.
Valve Rods
  • Steel, alloy steel.
  • stainless steel and brass.

Sanjack sucker rod pump workshop was established in 1964, which has more than 50 years of history. We have rich experience in production and a strong ability in research and development. Our products include various series of tubing pumps, rod pumps, and special sucker rod pumps. We obtained 32 national technology patents in the downhole pump. The machining workshop for sucker rod pumps is equipped with more than 200 sets equipment, including CNC lathes, milling machines, grinding machines and etc. The electroplating workshop of the sucker rod pumps enjoys countrywide advanced chrome plating equipment for well type deep hole pump barrel, which can process pump barrels ranging from 1 1/4 in (31.75 mm) to 5 3/4 in (146.05 mm) and with a length up to 34 ft (10363 mm). The sucker rod pump assembly workshop has honing machines and complete pump pressure testing devices and other equipment. Sealing performance tests must be carried out 100% after finishing the assembly of the whole pump to fully guarantee the quality of our sucker rod pumps.

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How to improve the service life of the sucker rod pump by improving the standing valve?

The standing valve test (SV test) is used to check the standing valve for leaks and is conducted with the dynamometer in place on the polished rod. At the start of the testing procedure, the pumping unit is stopped well into the downstroke (at about three-quarters of the way down) by switching off the motor and applying the brake.

The unit must be stopped gently to eliminate any dynamic load effects. The actual polished rod load is immediately recorded on the dynamometer chart by pulling the cord of the dynamometer. As shown in Fig. 6.15, the standing valve is in a closed position, whereas the traveling valve is open. Since liquid load is completely carried by the standing valve, the polished rod load recorded at the commencement of the test represents the buoyant weight of the rod string only.

In case the standing valve is in perfect condition and holds well, the polished rod load remains steady. Thus, a repeated recording of the load by pulling the dynamometer cord again results in a line that falls on the first measurement. After repeatedly pulling on the cord at regular time intervals, no changes in polished rod load occur.

If the standing valve is defective, then it will leak fluids from the tubing due to the high-pressure differential across its seat. As fluids leak from the space between the standing and traveling valves, the pressure immediately below the traveling valve will decrease, causing the traveling valve to close slowly. As time progresses, the traveling valve finally assumes the fluid load, which was originally carried by the standing valve. This transfer of fluid load will entail an increase in polished rod load, which is recorded at regular intervals (usually every second) on the dynamometer chart. As seen on the example card in Fig. 6.15, the original polished rod load (long horizontal line) increases as time progresses (indicated by the shorter lines), the rate of load increase being directly proportional to the severity of the standing valve leak.

In case of leaking standing valves the valve test should be repeated several times to check for consistency. If the same results are obtained, then the seat of the standing valve is cut, whereas a damaged valve ball is indicated if the valve seems to hold on some trials. Usually, a leaking standing valve shows a load increase in about 20 s. In no case should the measured load decrease; this indicates an invalid test, usually caused by stopping the unit before the traveling valve could open.

The standing valve of the sucker rod pump is a component that has a significant impact on the pump efficiency and service life of the sucker rod pump. The existing valve cage of the standing valve is limited by the OD of the pump barrel or the ID of the tubing, and the valve ball and valve seat are also installed inside. The small space makes the rigid wall of the valve cage thin.

Moreover, the valve cage always bears the alternating load and at the same time, it is frequently impacted by the valve ball during work. Therefore, with the extension of working time, under the repeated action of alternating load, the thin-walled part is elongated and hit and becomes thinner and thinner. Eventually caused the valve cage to suddenly break from the thin wall.The valve cage is broken due to the thin wall of the valve cage, low mechanical strength, alternating load and impact by the valve ball.

In order to improve the impact resistance of the valve cage and extend the service life of the sucker rod pump. Sanjack Group has developed a high-strength, anti-collision, wear-resistant standing valve assembly for sucker rod pump. The new type standing valve assembly is composed of valve cage assembly, valve ball, valve seat, and valve seat joint. Its structure is as follows:

2 Anti-collision sleeve
3 Valve Cage Assembly
4 Valve Ball
5 Valve Seat
6 Valve Seat Joint


The anti-collision sleeve is lined in the valve cage. The anti-collision sleeve is made of a polymer material based on high-density polyethylene.The anti-collision sleeve is pressed by the pressure cover and has axial and radial clearances between the valve cage body and the pressure cover of the valve cage assembly. When pumping oil, the crude oil pushes the valve ball of the anti-collision standing valve assembly to flow to the ground.

Because the oil well has a certain inclination, the sucker rod pump also has a certain inclination after going down the well, which causing the valve ball to open first when the valve ball is opened and closed. It also causes the valve ball to rotate and hit the side wall of the valve cage. The anti-collision sleeve of the valve cage assembly can effectively improve the anti-collision ability of the valve cage and prolong the service life of the sucker rod pump.


The new type standing valve assembly has a reasonable and compact structure. The anti-collision sleeve lined in the valve cage has excellent physical properties such as elasticity, flexibility, and abrasion resistance, which effectively improves the anti-collision ability of the valve cage, extends the service life of the sucker rod pump and reduces the cost of oil well operations.


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