Description The COBRA single stage, directdriven rotary screw dry vacuumpumps are designed for difficult applications in the pharmaceutical and chemical processing industries.

The COBRA NC series, B version vacuum pumps incorporate a unique, monoblock, variable pitch screw design. The variable pitch design operates more efficiently, has a higher CFM to horsepower ratio, and lower operating temperatures than traditional dry screw vacuum pumps.

The COBRA NC series, B version vacuum pumps provide vacuum down to .0075 torr, and pumping speeds up to 225 ACFM. They will operate at any pressure from atmospheric down to ultimate pressure. Direct cooled and closed loop radiator cooled models are available. For higher pumping speeds and lower ultimate pres-sure, Busch offers COBRA/booster systems along with many other custom designed vacuum systems.

Standard Equipment

• NEMA C-face motor, explosion proof Class I, Groups C&D, Division 1, Service factor 1.15

• Cooling water flow control system (for direct cooled models)

• Cooling water temperature switch and gauge

• Exhaust gas temperature switch

• Stainless steel exhaust silencer

• Exhaust check valve

• Stainless steel inlet flange

• Oil lubricated, mechanical shaft seals on the inlet shaft end

• Oil lubricated, mechanical shaft seals with piston ring labyrinth seals on the discharge shaft end

• Purge regulator for discharge end labyrinth seals

COBRA

NC 0100 - 0300 B

Dry Screw Vacuum Pumps ®

COBRA NC 0200 B

Dry Screw Vacuum Pumps

Operating Principle

Operating Principle

Two counter rotating screw shaped rotors rotate inside of a common cylinder. As the screws rotate, they trap a volume of gas at the inlet of the vacuum pump, and convey that gas towards the vacuum pump discharge.

The variable pitch screw design compresses the gasses more efficiently compared to traditional screw designs. This design creates up to 50% higher efficiency (CFM per horsepower), and reduces the temperature rise by up to 50%.

The screws do not contact each other or the cylinder/end plates due

to precision manufacturing and gears that maintain rotor timing. Therefore, no lubricant is required in the pumping chamber.

Lubricants for the bearings and gears are sealed from the pumping chamber by mechanical shaft seals.

Cooling is achieved by either a direct (once through) water cooling system which utilizes an integral coolant pump and flow controlling valve or by an integral coolant recirculating system, utilizing an internal liquid pump and a fan cooled radiator.

1 Inlet

2 Exhaust

3 Water Jacket

4 Screw

5 Oil

6 Gas Path

7 Timing Gears

8 Bearings

9 Shaft Seals

10 Oil Seal

11 Recirculating Pump

Application

• Drying processes in the pharmaceutical industry demanding special product purity

• Recovery of solvents, from drying, filtration, crystallization, and distillation processes

• Degassing processes in the furnace, metal and coating industry

• Degassing processes in the food industry

• Impregnation processes

• Crystal growing for semiconductor and solar industries

• Extruder degassing

• Recycling of process gases without adding contamination

• Vacuum separation of azeotropic mixtures

• Industrial furnaces

• Evacuation of gas bottles prior to filling with high-purity gases

• Leak testing

• Central vacuum for laboratory and pilot plants

• Sinter processes

• Coating technology

• Vacuum processes in all applications where oil-free vacuum is required

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5

5

10

11

6

4

32

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Cooling Systems

Direct Cooling System

The water in the cooling jacket of this system is continuously recirculated by a magnetically driven water pump that is mounted on the end of the pump shaft. An adjustable thermostatic valve maintains the fl ow of water into and out of the system so as to achieve an ideal jacket temperature. This system leads to a very thermally stable water jacket, and eliminates the need for constant operator monitoring of the cooling system.

Radiator Cooling System

An optional radiator cooled system is available for applications where a water supply is not available. This system uses a magnetically driven water pump to continuously circulate the coolant mixture through the cooling jacket and heat exchanger. The heat exchanger uses a shaft mounted cool-ing fan to remove heat and maintain an optimal operating temperature of the cooling system.

Technical Data

Technical Data NC 0100 B NC 0200 B NC 0300 B

Nominal pumping speed ACFM 82 160 225

Ultimate pressure Torr .0075 .0075 .0075

Motor size HP 5 10 15

Motor rotational speed RPM 3600 3600 3600

Sound level rating* (direct cooled) dbA 74 76 77

Approximate oil sump capacity Qts. 2 2 2

Average water usage rate (direct cooled) GPM 1 1 1

Approximate weight as shown (direct cooled) Lbs 730 908 1160

Approximate weight (radiator cooled) Lbs 798 976 1228

All performance data is based on ambient conditions of 14.7 PSIA and 70º F, and has a tolerance of +/- 10%.*DIN EN ISO 2151

240

220

200

180

160

140

120

100

80

60

40

20

00.001 0.01 0.1 1 10 100 1000

Pumping Speed vs. Inlet PressurePumping Speed (ACFM)

Inlet Pressure (torr)

NC 0200 B

NC 0300 B

NC 0100 B

12

11

10

9

8

7

6

5

4

3

2

1

00.001 0.01 0.1 1 10 100 1000

Brake Horsepower vs. Inlet Pressure Brake Horsepower (BHP)

Inlet Pressure (torr)

NC 0200 B

NC 0300 B

NC 0100 B

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Dimensions (direct cooled)

All dimensions in inches unless otherwise noted.

Dimensions J K L M N O P Q

NC 0100 B 105/8 11 81/8 87/8 91/8 161/4 63/8 151/2

NC 0200 B 14 111/4 81/8 93/8 91/8 161/4 23/4 151/2

NC 0300 B 111/2 111/4 81/8 93/8 91/8 161/4 33/8 155/8

Dimensions A B C D E F G (ANSI) H I (NPT)

NC 0100 B 531/8 265/8 241/4 14 23/4 311/2 11/2 24 11/4

NC 0200 B 61 265/8 26 141/2 31/4 415/8 2 243/8 2

NC 0300 B 651/2 265/8 28 141/2 31/4 441/2 2 243/8 2

Dry Screw Vacuum Pumps

Dimensions (radiator cooled)

ISO 9001 Registered Company

www.buschusa.com1-800-USA-PUMP

Busch - all over the world in industry

Busch LLC 516 Viking Drive Virginia Beach, VA 23452

Phone (757) 463-7800 FAX (757) 463-7407

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Models and specifications are subject to change without notice 02-1/08

Dimensions A B C D E F G (ANSI) H I (NPT)

NC 0100 B 531/8 371/8 241/4 14 23/4 311/2 11/2 24 11/4

NC 0200 B 61 371/4 26 141/2 31/4 415/8 2 243/8 2

NC 0300 B 651/2 367/8 28 141/2 31/4 441/2 2 243/8 2

Dimensions J K L M

NC 0100 B 105/8 11 63/8 151/2

NC 0200 B 14 111/4 23/4 151/2

NC 0300 B 111/2 111/4 33/8 155/8

All dimensions in inches unless otherwise noted.

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