PD top discharge centrifuges

Principle of Operation

PD series top discharge centrifuge is a new type of centrifuge designed and manufactured according to the conditions in China. Its driving motor can be not only started by a clutch, but also controlled by a variable frequency drive so it can start smoothly. The power is transmitted to the basket by means of a v-belt, causing the basket to rotate at high speed around its own axis, forming a centrifugal force field. The suspension to be separated is fed into the centrifuge basket at high-speed through the feed pipe installed on the cover. Under the centrifugal force, the feed is evenly distributed on the basket wall for centrifugation, the liquid phase in which permeates through the voids of solid particles and the pores of a filter sack and the basket into the housing and is discharged from the liquid outlet of the base plate, while the solid phase is intercepted in the filter sack. After stopping the machine, the cover is opened (by means of a specially designed balance device), the locking bolts of the cover are pulled out, and the filter cake is lifted out by a special filter sack lift-out device to the predetermined location outside the machine for discharge, with completing a operating process cycle. The cover is equipped with a wash tube via which the solids can be washed.

Main features

The design is innovative, using a quick-action filter sack lift-out device to discharge solids whose operation is convenient, fast, and labor-saving. The fully sealed design improves the working environment, avoids the separated products from cross-contamination, and meets GMP requirements. The nitrogen protection inside the centrifuge housing fully meets the sealed and explosion-proof requirements. With adopting a large cover, it is easy to discharge products and the process areas in the centrifuge can be thoroughly flooded with liquid. The cover is equipped with a mechanical balancer so that its opening is labor-saving and does not require the power. With a variable frequency device and the programmable control system, the startup is smooth, and the dynamic (feedback) braking is set by the program (feeding, filtration, washing, and other steps are fully automated) so there are no dust pollution and heat generated due to the mechanical braking friction, which makes the machine operation safer. The centrifuge process and outer surfaces have been polished without any dead zones all of which are large radius smooth transition connections with cleaning in place (CIP, filter cake cleaning, machine cleaning) to achieve the optimal washing effect. The machine is highly versatile and finds wide applications, with the crystal particles being not easily broken.

Designs options

The housing is a cylindrical and integrated to the base plate by welding. The machine is not equipped with variable frequency control system and started by a clutch with a manual braking mechanism. The basket is machined from stainless steel. An exhaust outlet and nitrogen filling inlet are opened on the housing and other design options according to customer requirements.

Constructure materials options

Due to the need for anti-corrosion, other materials can be available according to customer requirements, such as SUS316, 316L, 321, 304, titanium material, Hastelloy alloy, plastic lining, rubber lining, F46 spraying, Halar spraying, etc.

Standard configuration

PLC+variable frequency control, dynamic braking are provided. The machine is equipped with a standard filter sack，a vertical ordinary (or explosion-proof) motor and an on-site operation box (or button box). The motor is equipped with a protective hood, and a set of lifting tools is provided.

Standard design

The machine adopts traditional design, removable housing, the housing fixed onto the base plate with fasteners, the cover connected with the housing by flanges with a sealing strip, and the quick opening cover by means of a balance cylinder. The cover is equipped with the feed pipe, wash pipe, sight glass, illuminated lamp, air vent, etc. The basket body and its brim adopt a quick disassembly design, and the filter sack is installed on the removable basket brim that is connected to the basket body with locking bolts, which is safe and reliable under the centrifugal force. All components in contact with the slurry are made of stainless steel. The base plate is made of Q235, with 304 stainless steel lining on the top and sides, and paint spraying on the bottom surface.

Optional configuration

Oxygen content detection and ventilation system; Nitrogen protection system (automatic monitoring of pressure inside the machine and nitrogen filling); Liquid sealing device at the liquid outlet; PLC program control and feed level detection; Inclined feed disk, CIP device; Variable frequency drive and feedback (dynamic) braking system; Movable installation; Vibration isolators, etc.; Other configuration requirements.

Main constructure materials

The material of the base plate is Q235 lined with stainless steel. All other parts of the basket are made of stainless steel except for the HT basket bottom lined with stainless steel. The housing and cover (including its accessories) are all made of stainless steel. The bearing housing is made of cast steel or cast iron with lining of stainless steel. The balance spring cylinder is made of Q235.

PD top discharge centrifuge Standard Sizes and Technical Data