Ulvac DIS Dry Scroll Vacuum Pumps

A scroll pump gives clean, oil-free rough vacuum with no oil to change and no oil mist at the exhaust. Ulvac DIS pumps use a double-wrap scroll design that reaches deep vacuum for a dry pump, down to about 1 Pa (7.5 mTorr) on the largest model.

Ulvac, a Japanese vacuum equipment maker, builds DIS pumps for analytical instruments, leak detectors and backing turbo pumps. At Provac Sales, we supply Ulvac scroll pumps and service them in our own shop.

Ulvac Scroll Pump Models We Carry

DIS Two-Stage Scroll Pumps

• DIS-90, about 90 L/min at 50 Hz and 108 L/min (3.8 CFM) at 60 Hz, ultimate about 5 Pa, 150 W single-phase, KF25 inlet and KF16 outlet, 14 kg
• DIS-251, about 250 L/min at 50 Hz and 300 L/min (10.6 CFM) at 60 Hz, ultimate about 1.6 Pa, 400 W single- or three-phase, KF25 inlet and KF16 outlet
• DIS-501, about 500 L/min at 50 Hz and 600 L/min (21.2 CFM) at 60 Hz, ultimate about 1.0 Pa, 600 W single- or three-phase, KF40 inlet and KF25 outlet

DISL Single-Stage Scroll Pumps

• DISL models, such as the DISL-102 and DISL-503, use a single-wrap version of the scroll design

Single-phase models run on 100/115 V or 200/230 V, and three-phase models on 200/230 V or 380/460 V. Some listings show a price and others are quote-based. Each product page lists pumping speed, ultimate pressure, voltage and connections.

Scroll Pump vs Rotary Vane and Diaphragm Pumps

• A DIS scroll pump reaches much deeper vacuum than a diaphragm pump while staying oil-free.
• A rotary vane pump can reach lower pressure, but needs oil changes and can backstream oil into the system.
• Choose a scroll pump when you need clean rough vacuum, such as for backing a turbo pump, a leak detector or an analytical instrument.

How a Double-Wrap Scroll Pump Works

A scroll pump uses spiral-shaped scrolls. In the DIS design, one orbiting scroll moves between two fixed scrolls, which gives two pumping sections in one compact pump.

The orbiting motion traps pockets of gas at the outer edge of the spiral and moves them toward the center, where they are compressed and pushed out through the exhaust. Tip seals on the scroll edges keep the pockets sealed. The pump can start from atmospheric pressure and runs with low vibration and noise.

Air Flush and Thermal Protection

Water vapor from the process can condense inside a scroll pump. The DIS air flush bleeds a small flow of air through the pump to keep moisture from condensing. A built-in thermal protector stops the motor if it overheats and resets automatically once it cools.

Key Features

• Oil-free dry pumping with no oil changes
• Double-wrap design for deep ultimate pressure in a compact size
• Air flush to stop moisture condensation
• Automatic-reset thermal protector
• Starts from atmospheric pressure
• Hour meter for tracking the maintenance cycle

Applications for Ulvac Scroll Pumps

• Backing turbomolecular pumps
• Helium leak detectors
• Mass spectrometers and analytical instruments
• Gas recovery systems
• Coating equipment
• Semiconductor manufacturing processes

How to Choose the Right Ulvac Scroll Pump

Before ordering, confirm:

• Pumping speed needed for your chamber or foreline
• The ultimate pressure your process or turbo pump needs
• Supply voltage, frequency and phase
• Inlet and outlet flange sizes, KF16, KF25 or KF40
• Water or solvent vapor load, and whether you need the air flush
• Whether acid gas or oil mist needs an inlet or exhaust filter

Maintenance Tips

• Replace tip seals at the interval in the manual, using the hour meter to track run time
• Use the air flush when pumping water vapor
• Fit an inlet filter on dusty processes, or an SGT filter for acidic gas and oil mist
• Keep the cooling fan and air paths clear
• Run the pump inside its 5 to 40 °C ambient range

Signs Your Scroll Pump Needs Service

• Ultimate pressure has risen above its rated value
• Longer pumpdown than before
• Fine dust at the exhaust, which comes from tip seal wear
• New grinding or rattling noise
• The thermal protector trips often

Tip Seal Replacement

Tip seals are the main wear part in a scroll pump. As they wear, gas leaks back between the pockets and ultimate pressure rises.

A new set of tip seals restores rated vacuum in most cases. Bearings, scored scrolls or corrosion call for a full rebuild.

Ulvac Scroll Pumps Repair

Provac Sales services Ulvac DIS scroll pumps, including tip seal and bearing replacement. Submit an RMA request and complete the contamination data sheet before shipping. See our pump repair page for more information.

Related Collections

• Ulvac diffusion pumps, ULK and PBL oil diffusion pumps
• Shimadzu turbo pumps, turbo pumps that a DIS scroll pump can back
• Welch scroll pumps, SCSpro dry scroll pumps
• All Ulvac products
• All scroll pumps from every brand we carry

Find the Right Ulvac Scroll Pump

Send us your application, required pumping speed and ultimate pressure, supply voltage and phase, and the vapors you pump. We will recommend the right Ulvac scroll pump, confirm availability or quote tip seal service and repair.

Browse our inventory above or contact our vacuum specialists at 831-462-8900.

Ulvac Scroll Pump FAQ

1. What ultimate pressure does an Ulvac DIS scroll pump reach?

The DIS-501 reaches about 1.0 Pa, the DIS-251 about 1.6 Pa and the compact DIS-90 about 5 Pa.

2. What is the pumping speed of the Ulvac DIS-251?

The DIS-251 pumps about 250 L/min at 50 Hz and 300 L/min at 60 Hz, with a KF25 inlet and KF16 outlet.

3. Does an Ulvac scroll pump need oil?

No. DIS pumps are dry scroll pumps. There is no oil in the pump, no oil to change and no oil mist at the exhaust.

4. Can an Ulvac DIS scroll pump back a turbo pump?

Yes. Backing turbo pumps is one of the main uses for DIS pumps. Check the foreline pressure and flow your turbo pump needs before choosing a model.

5. What does the air flush on a DIS pump do?

It bleeds a small flow of air through the pump to keep water vapor from condensing inside, which protects the tip seals and scrolls on wet processes.