Thread structure as strength carrier

Stator reinforced by thread inlays Conventional tube stator
Elastomer Recycelingmaterial
without any outer shell for support 2 steel tube

Stators reinforced by thread inlays don´t need any outer shell for support. The thread reinforced stator, threads or mesh are embedded in the elastomer in one or more layers at defined angles in relation to the longitudinal axis. The thread / mesh structure forms the corset of the stator. Compared to common elastomers, the specific force transmission of technical threads is approximately 30-50 times higher, while the elongation is approximately 25-40 times lower

Fadenarmierte Stator

Both ends of the thread reinforced stator are flange like. Specially manufactured steel flanges with a 3D-design provide the necessary seal pressure and prevent the stator from rotating.

Depending on the manufacturing process, the outer shape of the thread reinforced stator can be circular or oblong hole shape with uniform elastomer wall thickness.

The latter is particularly suitable for larger dimensions, as up to 50 percent of the elastomer volume can be saved compared to conventional stators.


Thread reinforced stators can be specifically adapted to the corresponding customer application. There is a sheer endless variety of combinations in the selection of thread materials, thread designs, layer-dependent use of different elastomer qualities and layer structure, to name a few.

In this way, suitable combinations can be used, for example, to customise steering joint couplings for cars and trucks to the requested steering properties as specified by the customer.

SGF Coupling

For exhaust hangers, the thread reinforcement is also adapted to the respective vehicle according to customer specifications.

Modular stator concept

One- or two-stage stators can be combined to any n-stages stator.

Mehrstufigen Pumpe

Schematic example of a 2- / 3- or 4-stage stator assembled from 2 single-stage / 1x single-stage and 1x two-stage or 2x two-stage stators.

The design of the stator reinforced by thread inlays with its flanged connections on both sides enables two or more stators to be connected as a 2-, 3- or multistage pump for higher pumping pressures.

  • System advantages

The modular concept makes it possible to combine stators with different degrees of hardness, preload, stiffness, etc. For multistage pumps, there are thus many possibilities to find the best customer-specific design.

In addition, there are various possibilities to vary the preload manually or automatically – see “Control of preload ”.

Encapsulated stators with heating jacket, cooling jacket or pressure jacket (1) are also available as an option.

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  • Reduction of tooling costs

The modular stator concept reduces the variety of pressure related toolings to one and therefore it offers a good basis for automation at the same time

  • Assembly advantages
  • The modular stator concept considerably shortens the required installation space and ideally reduces it to the installation space of a single-stage stator.
    During assembly, one stator after the other is assembled onto the rotor and fixed in place, like wise a string of pearls.

  • Logistics advantages

Handling, storage and transport of long, bulky stators are a thing of the past. With the modular concept, the unpopular special warehouses and transport surcharges disappear.

Control of preload / overlap

Conventional tube stator

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1 Stator preload to rotor

With the appropriate alignment of the thread inlay, the preload to the rotor can be set specifically by the thread reinforced stator.
This can be used for:

  1. statically to compensate for wear to extend the service life, or
  2. temporarily to increase performance at certain operating points, or
  3. in a relaxed state to reduce the starting torque during the starting phase

Preload control options

1. Memory effect – physical

As can often be observed in nature, some mate-rials also store their original aggregate state and try to return to it when the temperature changes. Most plastic threads also exhibit this memory effect. It can be used to compensate for the loss of strength of the elastomer at applications with different temperatures of use. This process is also reversible and thus extends the range of application or improves the performance curve.

If the thread is selected appropriately, its hot shrinkage will increase the pretension if the operating point is in the temperature range where hot shrinkage occurs.

2. Mechanical
2.1 Longitudinal expansion

Elongation of the stator in the longitudinal direction automatically causes a reduction in diameter. This effect is enhanced by thread inserts if they are inserted at a suitable angle to the longitudinal axis. The spirally running threads move inwards when the stator is stretched longitudinally and thus increase the preload additionally.

2.2 Torsion

By twisting one end of the stator, the vulcanised threads move inwards and thus increase the pretension. Depending on the orientation of the thread inserts to the longitudinal axis of the stator, this readjustment effect is more or less intensified.

2.3 Pitch-neutral control of preload

This is the combination of longitudinal elongation in the axial direction and torsion analogously in the direction of the stator pitch.
The original stator pitch in the new state is not changed by the readjustment movement, i.e. it is readjusted specifically at the wear points. This is therefore the gentlest and most effective kind of adjustment to compensate for wear on the stator or to actively control the preload on the rotor.

3. Hydraulic

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Pitch-neutral control of rotor preload by pressurisation of the stator outer shell.
The design of the stator reinforced by thread inlays with its two flanged collars makes it possible to attach an outer casing (1). The completely encapsulated stator can be pressurised via a filling medium (2). By changing the filling pressure, the preload on the rotor also changes adequately. The hydraulic control can be realised entirely without mechanical components. It is completely wear and maintenance free. In addition, it can also be used in modular design i.e. for multi-stage pumps and can be individually adapted to each pressure stage, i.e. depending on the system pressure of the pump.


By actively controlling the temperature of the filling medium in encapsulated stators, the physical properties of the stator reinforced by thread inlays can be increased or reduced accordingly, regardless of the temperature of the pumped medium.

High performance technology

The thread elastomer composite technology changes the direction of action for force application and absorption. The thread inserts provide the necessary strength. They transfer the forces and thus reduce the stress on the elastomer. Established products – e.g. hoses, belts, tyres etc. – are evidence of high performance of this composite technology.


To produce a thread reinforced stator, only two components are needed. These are technical threads and elastomer (rubber).

Production of technical threads Elastomer (unvulcanized rubber)
Elastomer Recycelingmaterial

Nowadays, the economical use of natural resources is a matter of course. This is precisely where the thread reinforced stator offers immense potential thanks to its layered structure. For example, only the inner layer in contact with the medium could be made with a thin wear layer of the required elastomer quality. For everything else, cheaper elastomer qualities could be used, or possibly even products made partly or entirely from recycled material.

Depending on pump or stator size, the quantity of elastomer can be reduced up to 50 % compared to conventional stators. With a market share of approximately 10%, 700 tonnes of steel and 400 tonnes of elastomer could be saved annually. Additionaly carbon footprint would improve by 80% because of lower weight by transportations.

Vergleich Stratorgewicht

Worn, thread reinforced stators can be recycled more easily and in a wider variety, as they do not have a metal casing and are not fixed by chemical bonding system to it.


Stators reinforced by thread inlays for progressing cavity pumps offer many advantages

  • best cost-benefit ratio
  • lower operating costs
  • retrofittable
  • longer stator life
  • for some application longer rotor life
  • easy to assembly
  • up to 80% less weight
  • can be connected arbitrarily to form n-stage stators
  • saving of resources
  • better recyclability

Design advantages of stators reinforced
by thread inlays compared to state of the art stators.


In principle, thread reinforced stators can be adapted and retrofitted to any existing progressing cavity pump using a conversion kit. The conversion kit can be used as often as required and is designed in such a way that the pump can be returned to its original condition at any time. Ideally, two 3D flanges with the corresponding hexagon nuts, washers and lock washers are sufficient.

Conversion kit for initial assembly


Divisible 3D steel flanges with fastening material


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Get in touch with me. There are many possibilities for cooperation. Together we can forge a business model for our future.

Process steps required for stator production

State of the art stators

All kind of stators available on the market are equipped with a rigid outer shell consisting mainly of metallic materials. In most cases, the elastomer is firmly bonded to this outer shell via a chemical compound. This outer shell essentially performs the following functions:

  1. Sealing function on both sides via the sealing surfaces vulcanized to the end faces.
  2. Absorption of the clamping forces applied via the outer tie rods to prevent the stator from rotating.
  3. Support of the rubber inner contour

Hereafter the most commonly types of stators with their relevant properties and design features are listed.

  1. Conventional stators with tubular shell make up the vast majority of stators used. The elastomer thickness across the cross section varies greatly. At higher speeds, so called hot spots can occur in the thickwalled areas. These occur due to insufficient heat dissipation to the stator outer shell and lead to premature failure.
  2. Schnittdarstellung Schnittdarstellung
    Cross sectional view of a conventional tube stator with different elastomer wall thickness (smax smin) Cross sectional view of a stator with constant elastomer wall thickness (smax = smin)
  3. Stators with constant wall thickness or helical stators are more efficient than conventional stators. They have better heat dissipation because the elastomer thickness is constant over the entire cross section. Stators made of special materials are manufactured from solid material. More economical, however, are preformed tubes that are used as outer shells.
  4. Manually readjustable stators with tubular shell are offered with milled segments or as a longitudinally slotted version. With both versions, the service life can be extended by a manually adjustment mechanism. At these systems, the elastomer of the stator is firmly connected to a metallic outer shell.
  5. Automated adjustment mechanisms to regulate the stator preload increase the pressure on the separately manufactured, inserted elastomer stator. The elastomer stator is not connected to the supporting outer shell
  6. Wobble pumps are progressing cavity pumps whose rotating unit is designed with only one joint. The stator is flexibly connected.

Properties of the stator reinforced by thread
inlays compared to state of the art stators.


The “Global Progressing Cavity Pumps Market” forecast a sales volume of approximately US$ 742 million, round about 668 million Euro, for this pump industry in 2019.

The aftermarket for stators is estimated to amount to approximately 107 million Euro worldwide in 2020. Hereof the German / European market share is estimated at approximately 15 / 64 million Euros.


Progressing cavity pumps

Progressing cavity pumps or progressive cavity pumps colloquially also known as worm pumps or screw pumps.


PCP is the English abbreviation for Progressing Cavity Pump or Progressive Cavity Pumps, also known as PC Pump.

Reinforced by thread inlays

Does also include reinforcement by thread mesh. Rubber thread compound technology makes the stator much more stronger.

Technical threads

Technical threads are especially developed for industrial application. Common raw materials are e.g. Nylon, Polyester, Aramid, Rayon

Hot Spots

Hot spots are locally limited areas in the stator elastomer which has significantly higher temperatures during operation due to insufficient heat dissipation which could cause damage to the stator.

Fadenarmierte Stator

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Vergleich Stratorgewicht

Vergleich Stratorgewicht

Vergleich Stratorgewicht

Vergleich Stratorgewicht