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Underwater Pelletizer

Under water pelletizer is widely used in plastic granulating industry, it can process almost 90% of different plastics compounding & granulating. The automatic cutting and complicated controlling, alarm sytem allow customer to save manpower and waste material, moreover, the final granule is in better shape and uniform size which is easier to be accepted on the market.

CWT40-plus+Underwater Pelletizer_

As a professional producer of underwater pelletizing systems, Cowell has extensive knowledge and expertise in various polymer processing techniques that can help you get better products. With our unique heat insulation and die plate design, it can process a wide range of polymers, such as thermoplastics, hot melt, masterbatches, engineering plastics etc.


Sample Applications



Color Masterbath
Filler Masterbatch
Additive Masterbatch





Hot Melt

EVA hot melt, TPU hot melt, PA hot melt, Etc.


Biodegradable Materials

PLA, PBAT, etc.

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Under Water Pelletizer Features

Optimized die head flow channel design enables stable outlet & uniform spherical pellets.

Unique heat insulation design to avoid melt frozen and block the hole, meanwhile can reduce the heat loss as well.

Uniform temperature heating system.

Automatically knife feed system.

Customized design.

HMI one key operation.

Under Water Pelletizer

●Specifications of Under Water Pelletzer

No. of Holes(holes)2-612-1818-3642-7260-10072-120
Hole Diameter(mm)0.5-3.20.5-3.20.5-3.20.5-3.20.5-3.20.5-3.2
Heating Power(kw)

Composition Of The Underwater Pelletizer

1. Diverter

The diverter is used to confirm the polymer melt is well melted in the extruder or reactor, etc. The diverter will be switched to the discharge position, and the polymer melt will be discharged into a box under the diverter. Operator can check the polymer melt there.   If the polymer melt is fully melted, then the operator will switch the diverter driven by the hydraulic station to the working position, and the polymer melt will go through the diverter to the under water die head for extrusion.

2. Underwater die head

The core part of the underwater pelletizer is the die head.  COWELL has unique technology to design the die head according to different polymers and applications.  The flow channel and hole is smoothly manufactured without dead corner. The special insulation technology guarantees the melt coming from the upstream can be properly heat-insulated here to make sure the melt could not be frozen at the die head, which blocks the die hole and affects the cutting. There are different ways to heat the die head, cartridge heaters, oil heating, and electromagnetic heating. The ways to chose the heating depend on the raw materials and the capacity.

3. Pelletizer

The pelletizer is to cut the materials coming from the die head. The pelletizer runs at high speed to cut them quickly in the water. The pellets/granules will go with the water flow. The knife contacts the die head face tightly driven by the compressed air or hydraulic station.  Both ends of the knife is alloyed steel made which could be used to cut the polymer.

4. Tempered water system

The tempered water system gives the properly heated water to the die head chamber to make sure the polymers could be cut perfectly.

The heating temperature could be preset via the HMI. And with efficient heat exchanger, and filtering system, guarantees fluent cutting.

5. By-pass pipe

The by-pass pipe unit is also an important part of UWG. The diameter of the pipe decides the water flow rate that is need for the material and the capacity. With different circulation designs, the whole system could be operated perfectly.

6. Centrifuge dryer

The centrifuge dryer, as is known, main function is to separate the water from the pellets/granules. The system adopts European experience and technology, further more, we have upgraded the design, making it more suitable and stable during operation.

7. Smart controlling system

The whole system is controlled by PLC and HMI. With one key start/stop. Interlock with upstream equipment. Temperature, rotation speed, pressure, flow rate display, data storage, alarm analysis, one key reset, etc.
Typical Applications:
Thermoplastics: TPE, TPR, TPV,etc
Hot melt: EVA, TPU, PA etc
Biodegradable materials: PLA, PBAT, etc


COWELL team is extraordinary experience in various applications based on their rich working experience in the past decades. We could give perfect solutions to your requirements with our know-how on extruder design and material processing.
The most important is that a customized solution on your extruder project is available for you from our team. Any difficult process could be done on our lab extruder and analyse the possibility to make it succeed on the scale production extruder. Some special design which helps to make the qualified product are available here from us.
We not only provide extruder, but we provide the whole turn-key system for you. Making your product more competitive on the market. We create value for you.

Definitely, we can design our underwater pelletizer to match your extruder, including connection, capacity and controlling interlock. We can provide a full replacement proposal for your application.

Our underwater pelletizer does not need additional operators since it is an automatic operation designed with a one-key start/stop.  So you can keep your current operators to run it together with your main machine.

The change over time depends on the size of the die plate. The average change over time is 1-2 hours.

COWELL has large quantity of standard parts in stock, we can send them very fast via Express. Meanwhile, we will give you some spare parts for emergency use as free spare parts and also will give suggestions for the fragile spare parts purchased during the quotation and order.


Color Masterbatch Compounding Line

Twin Screw Compounding Line

COWELL has launched its CWT52-Mega twin screw compounding line for our Russian customer, the largest masterbatch manufacturer in Russia.

Additive Masterbatch Extruder Line

Additive Masterbatch Extruder Line

UV-stabilized masterbatch, optical bright masterbatch, anti-oxidant masterbatch and anti-block masterbatch mostly used for the film industry like BOPET film. Meanwhile, those additive masterbatches are proved a good result for the textile industry like PSF, PSY POY.

PVC Compounding Line

PVC Compounding Line

COWELL CTS65-180 cascade extruder ordered by Zhongtai Chemicals, the largest PVC resin supplier in China. In order to expand their products range,they initiated a 350000 T annual production plan for PVC compounds since 2019. COWELL was selected as the extruder supplier among their various equipment suppliers.


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