Screw vacuum pumps

Features and Function

The screw vacuum pump is oil-free and exhausts means is a combination of two helical rotors with different directions of thread. Compressor housing and screws form a special form of the compression chamber for gas transportation.

Advantages of this type of pumps:

• high pumping speed
• the absence of oil vapors in the work area
• limiting pressure below 10 ^-2 mm Hg
  
• work on the atmospheric pressure
• resistance to liquid and vapor content in the pumped medium.

Pumped volume is connected to port 1. Both screws 3 rotate and redirects the gas through the chamber formed between the screws. Moving the camera 2 to the outlet, where the pumped gas is released. During the pump requires a cooling water flow of 5 l / min or more, depending on the model. In the illustration: 4 - seals, 5 - 6 bearings - drive -val 7, 8 - the case of cooling.

Screw vacuum pumps Screwstar (South Korea)

Through a series of "know-how" and technical solutions in the construction of housing and screw pair distinguishes the operation of these pumps from other types on the market of mechanical pumps, also known as "dry": three-blade, claw and screw pumps.

Become familiar with the company's model range ScrewStar in English you can on the official website of the company. Key benefits of this manufacturer of pumps, we list below. SS series pumps are reliable in operation and safety in the dry mechanical vacuum pumps are screw type, suitable for most industrial processes, including chemical industry, medical industry and pharmaceutical industry.

The main feature is a hybrid form of the screw rotor with variable pitch thread rotor. As a consequence, the compression mechanism of the gas stream occurs evenly along the entire length of the rotor, and the heat released as a result of the compression work, does not accumulate in the same point on the surface of the rotor or in the end caps. In operation, the two rotors form a hybrid with a variable pitch screw thread arranged horizontally and rotate the pump body without any mechanical contact towards each other in the clockwise and counterclockwise, respectively, by timing gears.

Another distinguishing characteristic compared to other products on the market is a mechanical pump housing material and rotor pump - used ductile iron that ensures stability, mechanical precision of the linear dimensions of the pump during the entire period of operation.

Also not unimportant that the interior of the pump, as the housing and rotors treated Teflon coating. This gives additional advantages to the use of these pumps when pumping process gases with high humidity and / or content of chemically aggressive components.

Grease double row angular contact ball bearings ensures oil cooking spray while rotating clock gears. For reliable sealing on the pump shaft from the oil sump and atmospheric pressure using high-lip seals and mechanical seals. 
Visual comparison of the pumps claw and screw type:  

Comparison of the screw and claw pumps

Claw pump consists of approximately 500 parts	Screw pump - of about 150 parts

Basic specifications Screwstar screw pump are shown in the table.

Characteristics of vacuum screw pumps

Model	SS150	SS300	SS 400	SS800	SS1500
Pumping speed 50/60 Hz, m3/h	110/130	250/300	330/400	660/800	1250/1500
Limiting residual pressure, mmHg	7.5 X 10 -3
Drive power 50/60 Hz, kW	2.2 / 3.7	5.5 / 5.5	7.5 / 11	15/15	30/37
The noise level in dB	79/85
The maximum rotational speed of 50/60 Hz, rev / min	2900/3500				1450/1750
Nominal diameter inlet / outlet flange, mm Standard flange JIS B2220	40/40	50/40	65/50	100/65	125/80
Oil volume, l	1	2	2	2.5	8
Type of gear oil	Shell Turbo Oil T-46 Mobil SHC629 (Heavy Duty)
Type of bearing lubrication console	Mobile 1 Grease (for industrial applications) Fomblin RT15 (for chemical applications)
Gas flow to purge the shaft seal, nl / min	5 ~ 15				15 ~ 25
Purge gas pressure, atm	1.3-1.5
Type of connection for connecting the purge shaft seals	Thread G1 / 4
Cooling water consumption, nl / min	5 ~ 10	10 ~ 15	10 ~ 15	15 ~ 20	30 ~ 40
Cooling water temperature min / max, ℃	5 ~ 35
Maximum allowable pressure water bar. huts.	10
The nominal loss of water pressure, atm.	2
Connection type to connect the cooling water	Thread G1 / 2
Recommended warm-up time of the pump, min	40
Type of shaft seal	HV (on the side of the vacuum): Double lip seal LV (on the side to the exhaust): Lip + Mechanical seal (with a nitrogen purge). Under the order can be double lip seal (with a nitrogen purge) DE (by resulting in a shaft): oil seal
Weight, kg	200	300	380	600	1200

Possible non-standard design of the pump, with the use of external control equipment directly to the needs of your process.

Additional elements for the pump

Meter inlet temperature of the vacuum pump: the thermal converter Pt10 0-24VDC, 0-20 mA, 0-200 o C
Temperature meter on the output of the vacuum pump: the thermal converter Pt10 0-24VDC, 0-20 mA, 0-200 o C in the protective performance
Temperature gauge in the case of the vacuum pump: the thermal converter Pt10 0-24VDC, 0-20 mA, 0-200 o C in the protective performance
The temperature sensor at the inlet end of the vacuum pump: PTC thermal switch two-threshold (the default threshold of 88 o C and 95 o shutdown threshold C) in the protective performance. On request thermal switch can be replaced with any other device thresholds.
Pressure gauge at the outlet of the vacuum pump: the strain SP400 converter 0-24VDC, 0-20 mA, 0-200 o C Type of protection
Panel mounting - 1 set, consisting of: Visual indicator coolant flow Pressure switch purge gas flow Manual valve cooling water supply Manual drain valve cooling circuit Valve manual feed nitrogen