NETZSCH Pumps Universal Parts

Progressing cavity pumps is a member of positive displacement pumps. The pump name explains the pump type and how this type of pumps work. Progressing cavity pumps are also known as Progressive Cavity Pumps, PC Pumps, Cavity Pumps, Progg Pumps, Screw Pumps…

A rotating rotor and a stationary stator are the main components of the progressing cavity pump. The rotor is a helical and round-threaded shaft. It’s running inside and matching with the stator. The stator is a hollow tube and be with an elastic lining inside. Please be aware the pump stator has the same pitch length as the pump rotor. Based on this, it leaves conveying spaces between the hollow stator and the helical rotor. Then the viscous medium can move continuously from the inlet to the outlet side.

Well, when there is a problem with your progressing cavity pump. You need to firstly check what the problem is and which part caused the problem. Normally, you need a professional staff to disassemble, check and replace the damaged parts when the flow rate and pressure decrease, or there is abnormal noise in the pump or the pump fail to rotate, etc. When the damaged part is found, the professional staff would tell you the damaged part number or part name.

When you check the PC pump models, you will find an indication of the pump stage. To know the pump stage quantity, we have some suggestions.

For a screw pump in the off state, a simple way is to calculate the ratio between the length and diameter of the stator. The ratio will give you an indication. Generally, when the ratio is between 2 and 2.5, it’s probably a single-stage PC pump. When the ratio is between 3.5 and 5, it’s probably a two-stage cavity pump.

Of course, some types of PC pumps don’t follow this rule. For example, dosing pumps’ ratios can be somewhat different. And for the extended single-stage pumps, it is only possible to know the stage quantity by disassembling the pump and counting their cavity numbers. Let’s say one stage corresponds to 2 complete sinusoids or 2 cavities (one hollow and one hump).

To quote you good prices quickly, we need your help to share some necessary information. When you are interested in some replacement spare parts for NETZSCH/MONO/SEEPEX… Please don’t hesitate to let us know the PC pump brand, pump models and the replacement part numbers/names. For example: “Hi, I am interested in part number 3005 and 1999 for NETZSCH pump NM021-02S.” Another simple way, you can share with us a picture of your pump label. Then we can know the points from that label quickly.

A rotating rotor and a stationary stator are the main components of the progressing cavity pump. The rotor is running inside and matching with the stator. However, it’s not necessary to change the rotor each time when the stator is replaced. Generally, the progressive cavity pump rotor should be replaced after 3 or 4 stator replacements. Of course, please pay more attention to the replacement frequency when the PC pumps are used in very abrasive applications.

Although, it is advisable to change the rotor soon after you find marks on the rotor or when the rotor section is no longer circular. Because, once that happens, the rotor wear would decrease the pump performance or even may prematurely damage the stator and cause severe loss.

Frequent maintenance may mainly be caused by pumping system problem, improper pump model selection or incorrect material selection of the pump parts.

1. When the problem is from the pumping system, the most common fault it causes is pump dry grinding.
2. While improper PC cavity pump model would make the spare parts wear out quicker, or even fail to work sometimes.
3. When you select the improper raw materials for the pump parts, the spare parts may easy to corrode and wear quickly. Then they would have a much shorter service life.

Anyhow, please don’t hesitate to reach us and ask for a suggestion when you face the frequent maintenance problem. We would share with you a valuable solution before you buy the cavity pump replacements.

Before we decide the raw material for the progressive cavity pump rotor, we must consider the pump working conditions and the medium which go through the PC pump. That means we should take chemical compatibility and wear resistance into consideration.

When the medium is chemically corrosive, we normally suggest stainless steel (SS304/SS316/Duplex stainless steel) or titanium alloy. For example, stainless steel rotors are usually applied in food industry. For the specific stainless steel serial number, please feel free to EMAIL US for detailed suggestions.

When the medium going through the pump contains fine particles, we have to fully consider the wear resistance of the pump rotor. You can select a harder raw material such as hardened tool steel or add a hard plating layer to the rotor surface, for example HCP(Hard Chromium Plating). For further suggestions, don’t hesitate to CONTACT US.

The stator is one of the main parts of a single screw pump. A screw pump stator usually consists of two items: the external shell and the internal lining. Specifically, the shell material normally is metal. For example, carbon steel with painting or stainless steel. And the lining is made of elastomeric plastics. According to your pump application, you can select one from NBR, HNBR, KFM, EPDM, PTFE, etc.

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