Description

Busch COBRA NC A series vacuum pumps feature our unique one-piece, fi xed-pitch, screw profi le rotors. Ideal for harsh applications in the chemical and pharmaceutical industries, COBRA pumps are also well suited for any application requiring oil-free compression along with high suction capacity at low operating pressure.

All pumps have a single-stage, dry-running, non-contacting design, are water-cooled standard (air-cooled optional) and are direct-driven by explosion proof motors. For applications requiring higher pumping speeds and/or lower end pressures, combination booster/pump systems are available.

Quiet running, COBRA pumps are easy to install and maintain, are suitable for variable speed operations and feature an overall low cost of ownership.

Dry screw vacuum pumps

COBRA NC 0250 A

Features

•Single-stage design

•One-piece screw casting

•100% dry compression

•Non-contacting internal components

•Protective coating on internal components

•Low vibration and noise Levels

•Small footprint

•Suitable for variable speed control

COBRA

NC 0070 - 0250 A

Standard Equipment

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

•Purge regulator for discharge end seals

•Cooling water fl ow 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 fl ange

•Pump stand

•Fully assembled and tested

®

Operating Principle

Two counter rotating, non-contacting screw shaped rotors rotate inside of a common cylinder. As the screws rotate, a volume of gas is trapped at the inlet of the vacuum pump, and the gas is conveyed towards the vacuum pump discharge.

Due to non-contacting screws, no lubricant is required in the pumping chamber. Lubricants for the bearings and gears are sealed from the pumping chamber by shaft seals.

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

Operating Principle

Dry screw vacuum pumps

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

Applications

• Chemical

• Pharmaceutical

• Solar

• Metallurgy

• Vacuum packaging

• Food processing

• Plastics

• Renewables

• Laboratory

Accessories

• Inlet filters

• Liquid separators

• Knock-out pots

• High volume bag filters

• Control valves

• Gauges

• Switches and transmitters

• Motor starters

• Variable speed drives

• Gear oils

• Vacuum receivers

2

1

5

5 10

6

4

3

2

7

8

9

8

*Performance based on ambient conditions of 14.7 PSIA and 70o F, and have a tolerance of +/- 10%. ** DIN EN ISO 2151

Technical Data

Technical Data

Nominal pumping speed*

Ultimate pressure

Motor size

Motor rotational speed

Sound rating**

Approx. oil capacity

Average water usage rate

Approximate weight

Pumping Speed vs. Inlet Pressure

ACFM

Torr

HP

RPM

dB(A)

Qts.

GPM

Lbs.

NC 0070

50

.075

5

3600

75

2

1

850

NC 0160

115

.075

7.5

3600

82

2

1

1000

NC 0250

180

.075

15

3600

82

2

1

1200

0.01

200

150

50

0

Inlet Pressure (Torr)0.1 1 10 100 1000

100

NC0250 A

Pumping Speed (ACFM)

NC0160 A

NC0070 A

®

Direct Cooling System

The water in the cooling jacket of this system is maintained at a constant temperature through the continuous exchange of cooling water entering and leaving the pump water jacket. A manually operated needle valve and water outlet temperature gauge are installed on the system to allow for precise water fl ow adjustment in order to achieve an optimal pump operating temperature.

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 cooling fan to remove heat and maintain an optimal operating temperature of the cooling system.

Cooling Systems

Dimensions (direct-cooled)

Dimensions

NC 0070 A

NC 0160 A

NC 0250 A

Dimensions

NC 0070 A

NC 0160 A

NC 0250 A

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

57 34 431/2 183/8 40 75/8 441/8 11/2 11/2

66 34 437/8 175/8 401/2 7 44 2 2

66 34 44 143/4 401/2 7 44 2 2

J K L M N O

50 11/4 27 243/4 83/4 377/8

59 0 271/4 26 101/2 377/4

59 0 271/4 251/8 101/2 377/8

All dimensions in inches unless otherwise noted.

32"

AB

1" J

C

E

G

26 1

/ 4"

22 1

/ 4"

16"

3 1/2"

O

NM18 1/4"

F

L

30 7/8"

D

DischargeI

InletH

K

4 x o 5/8"

21"

®

Busch LLC 516 Viking Drive Virginia Beach, VA 23452

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

COBRA NC-07-07/10

Busch - all over the world in industry

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www.buschusa.com1-800-USA-PUMP

Models and specifications are subject to change without notice

Dry screw vacuum pumps

ISO 9001 Registered Company

Dimensions (radiator-cooled)

All dimensions in inches unless otherwise noted.

Dimensions

NC 0070 A

NC 0160 A

NC 0250 A

Dimensions

NC 0070 A

NC 0160 A

NC 0250 A

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

57 34 523/4 183/8 40 75/8 441/8 11/2 11/2

66 34 53 175/8 401/2 7 443/8 2 2

66 34 531/8 143/4 401/2 7 44 2 2

J K

307/8 50

307/8 59

31 59

32"1"

AB

K

C

E

G

26 1

/ 4"

21"

16"

3 1/2"

18 1/4"

D

F

4 x o 5/8"

InletH

DischargeI

J

®