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Claw Type Dry vacuum pump v/s Coated Horizontal Dry screw vacuum pump

 

Introduction

 

The Dry Vacuum Pumps are gaining prominence in the Process Industries owing to the high quality of Vacuum, lower maintenance and Clean Process with a minimal environmental footprint. Since they are engineered to handle a robust environment, they have been proven as a trustworthy and optimum solution for the pharmaceutical industries and those dealing with chemical processing.

 

Let us understand what a Dry vacuum pump is, and why is it preferred?

 

As the name suggests, dry vacuum pumps do not require any fluid to create a vacuum, and hence the chances of product contamination are zero. The pumps have an integral cooling jacket to offset the heat generated during the pumping process.

The dry vacuum pumps are mainly categorized as under:

 

1. Screw vacuum pump

2. Claw vacuum pump

 

Let us understand each one in brief.

 

1. Screw vacuum pump

 

It is a kind of suction and exhaust instrument that uses a pair of screws to make a high-speed reverse rotation in the pump housing. In this, two screw rotors rotate in opposite directions in the pump shell with high speed to draw in vapours and then are discharged out. The screw vacuum pump is an advanced and improved design of a vacuum pump that results in lower electric energy consumption and maintenance-free advantages.

 

2. Claw vacuum pump

 

In this type of pump, multi-stage rotors are used wherein each stage comprises two rotors. The two rotors rotate in opposite directions to create compression and expansion. In this pump, two compression cycles are completed through a full rotation of claws. As they rotate, the claws take in Vapour through the inlet, and the pump compresses the vapour. 

 

What is a coated dry vacuum pump?

 

To protect the base metal against the chemical attack, a coating is provided to the vacuum pumps. It is a chemically inert layer, made up of polymer applied for protection on metallic surfaces. The main drawback of coating is that it cannot protect against abrasion.

 

We are giving a detailed comparison of our four-stage Vertical uncoated Dry vacuum pump against the Screw coated Dry vacuum pump.

 

COMPARISON OF OUR DRY VACUUM PUMP WITH OTHER COATED DRY VACUUM PUMP

 

Sr No

Selection Parameter

Vertical Uncoated Dry Claw type Vacuum Pump

Horizontal Coated Dry Screw Type Vacuum Pump

 

 

Origin

India (100% Made in India)

Korea/Germany/China/Japan

 

Application point of view

1

Suitability  for Low boiling  solvent

Yes

Yes

 

2

High Boling solvents like Toluene/ Xylene

 

Yes

No Condensation take place in pump causing damage to coating

Coated pump suitable up to 80 Deg C & hence not suitable

3

Permissible  Temp

120 Deg C

80 Deg C

 

4

High compression ratio

Yes. Pump alone work for 1 torr distillation.

No. High compression ratio increase temp in pump beyond  80 Deg C. Reducing life of coating

 

5

Higher Gas inlet temp

Yes .Allowed  55 Deg C

As pump suitable for 120 Deg C working temp.

NO. At higher gas temp, coating  will be  damaged & screws will be  seized

 

6

Can Handle condensate?

Yes. 60 LPH handling capacity.  The Vertical design enables the condensate to drain out

No Only 10 LPH Handling capacity. Due to a Horizontal design, the condensate remains inside. Damage to coating, bearings & mechanical seal

 

7

Can handle Particulate in case of  sublimation

Yes. The Particulate can easily drain out. Uncoated & hence no damage & No costly maintenance

No. The Coatings on the Screw might face erosion. Coating life will be shortened.

 

8

Can handle carbon particles in case of gas cracking at High temp?

Yes. Not affecting pump performance

No. The PEEK/PFA/Ni+ PFA/Ni + PEEK Coating will be damaged resulting in long drawn and expensive maintenance of the Screws and the Coatings

 

9

Can handle corrosive gases, acidic vapour?

Yes. Our pumps  are  working for Thionyl Chloride and other Acidic Vapours

Yes so long coating is intact. Once coating damaged/eroded, the corrosion will be faster.

 

Pump  performance

11

FAD Capacity@2900 RPM

300 M3/HR

250-267 M3/HR

 

12

Ultimate vacuum

0.06 Torr

0.5 to 1 torr

 

13

Capacity @ 10 torr

300 m3/hr

250-267 m3/hr

 

14

Capacity @ 1 Torr

300 m3/hr

240 m3/hr

 

15

Capacity @0.1 torr

100 m3/hr

Zero 

 

16

Permissible discharge pressure

1300 mbar

1013 mbar

 

17

Can we install  a scrubber in discharge ?

Yes

No

 

18

Will increase in back pressure create problem in pump performance?

No

Yes. Motor may trip & condensation take place

 

19

Connected Load?

15 HP

10 HP

 

20

Absorbed power @ 10  torr?

12 Amps

12 Amps

 

21

Motor Tripping

Never

Some times when condensation take place in pump or particulates are trapped between two screws.

 

From Maintenance point of View

22

Need  to replace motor

No

Yes

 

23

Do we need to send pump outside of the Plant for maintenance & Coating?

No

`

 

24

Opening of bearing  & Assembly

Easy

Easy

 

25

Dismantling of Pump?

Easy at site

Send to work shop.

Takes long time

 

26

Assembly of pump

Easy at site  with filler gauge

Not easy. Takes long time. If clearance are not maintained blank off vacuum cannot be achieved.

 

27

One year non interrupted  services

Yes. We have many installations running for more than 1 year without service break down.

No. Coating & Mechanical seal may fail any time at the cost of Production losses & Expensive maintenance cost

 

28

Maintenance  cost

Negligible. Cost for consumable like grease &oil. No other maintenance cost

Very high coupled with long production losses.

 

29

In case of Pump Jamming/Seizure?

Pump will be free after pouring diesel or suitable solvent.

Will take 2-3 hours.

No damage to pump internals in absence of coating

If coating damage than recoating will cost close to INR 4.0 Lac & pump will be out of service for Two months.

Recoating may not reliable

 

30

Oil bath / Grease chamber sealed by?

By Lip Seal which is Economical & reliable takes  very less time

Fitment  1 hours

Cost of lip seal not more than 10K

By Mechanical seal. Expensive time consuming & skilled person required.

Repair time   2 days.

Cost of  Mechanical seal INR 50K - 1.0 Lac

 

31

Cost of consumables

Like oil, grease , bearings?

Economical since indigenous parts. Readily available in market

Imported grease & Oil.

Not easily available in market

 

32

Can dry vacuum pump work in Multiple applications?

Yes

No. Suitable   for low boilers like Methanol, Acetone, Ethyl acetate. But not suitable for Toluene/Xylene & other  high boilers

 

33

Solid Foundation

Not Required

Required

 

34

Foot Print 

1200 X 1100 MM

2000 X 500 MM

 

35

Vibration

Normal. No solid foundation needed.

Solid foundation needed to protect mechanical seal & proper height needed to install post condenser & receiver for solvent recovery & to reduce back pressure.

 

 

 

Coated Horizontal Dry Screw Vacuum Pumps are not suitable for following Solvents

Solvent

Boiling  Point

(°C)

Solvent

Boiling  Point  (°C)

Solvent

Boiling  Point

(°C)

Acetic Acid

118.0

Benzene

80.1

tert-Butanol

82.5

Acetic Acid Anhydride

139.0

Iso-Butanol

107.7

Chlorobenzene

131.7

Acetonitrile

81.6

n-Butanol

117.7

Cyclohexane

80.7

Dimethyl Acetamide

166.1

Ethylene Dichloride

83.5

Hydrochloric Acid

84.8

Dimethyl Formamide

153.0

Ethylene Glycol

197.5

Iso-Propanol

82.3

Dimethyl   Sulfoxide

189.0

Heptane

98.4

n- Propanol

97.2

Pyridine

115.3

      Xylene

140

Toluene

110.6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Today our dry vacuum pump is a preferred choice in the chemical & Pharmaceutical segment.

Zero maintenance & less repair cost, and less downtime, are significant factors for our pumps' success.

 

Conclusion

 

The Vertical Claw type dry vacuum pumps offer a hygienic and fluid free vacuum solution for the pharmaceutical and chemical industries. They are best in handling the fluids, causing corrosiveness. The design of a dry vacuum pump offers a low operation and maintenance cost with no major impact on the environment.

 

About HIS Pumps & Systems Private Limited

HIS Pumps and Systems is a Solution Provider for Claw Type Dry Vacuum Technology to the Process Industries. With over 120+ Installations and with a combined experience of more than 25 Years, we have a proven track record of providing Premium, Proven and Reliable Vacuum Solutions to Pharmaceutical, Chemical, Agro Chemical and Fertilizer Industries.

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