Product Name. Quantity: 2. Continue shopping. Product Gallery. Accepted at Checkout. Last 5 Products Reviewed. Be sure to call Welch technical service prior to start-up at if you have any questions. Review the power source and the motor rating to be sure they agree in voltage, phase and frequency.
On threephase applications the direction of rotation of the motor must be considered. Make a momentary check rotation at the time of power installation and wiring. Momentary backward rotation of the pump is not harmful. Check the layout drawings for proper direction of rotation. Make certain the power settings on the pump match your power source before attempting to operate the pump.
Motor thermal overload protection is made available by the motor manufacturer as an aid to minimizing motor failure. Overload protection is a standard feature on all single-phase 60Hz motors. Single-phase motors will normally have automatic overload protection. Installations of such equipment must comply with local electrical codes which dictate appropriate starter and protection devices. It is strongly suggested that you familiarize yourself with the protection supplied with your motor so that you may react accordingly in the event of an emergency.
Automatic reset protection is designed to reset itself after a predetermined cooling period. If the fault to the drive remains unaltered, the motor will cycle on and off until the fault is corrected. The motor data plate will indicate the presence of thermal protection.
It has been shown that the conductance of a tube is proportional to the cube of its radius and inversely proportional to its length. Therefore it is imperative that the connecting lines be as large in diameter and as short in length as practical. For best results the diameter of the connecting tube should be at least as large as the diameter of the pump intake.
To avoid a large reduction in pumping speed at the vacuum chamber, it is clear that the conductance of the line must be considerably greater than the speed of the pump. If metal piping or tubing is used, it is preferable to solder or braze all of the connections. Flanged connections with elastomer gaskets make excellent demountable joints. Where metal tubing is used between the system and the pump intake, joints can be make by butting the ends of the two sections together in a short section of vacuum hose.
Worm-screw band clamps are useful for securing the hose to the tubing. Whatever the joint you choose to use, cleanliness should be of utmost importance.
Metal valves or stopcocks may be used in the connecting line between the system and the pump to provide a means of isolating the pump from the system. Where corrosive vapors or large quantities of condensable vapors are evolved from vacuum processing, a cold trap may be used in the connecting line to the pump.
It will help prevent damage to the pump mechanism and reduce oil contamination. Commonly used refrigerants are liquid nitrogen or dry ice and acetone.
The refrigerant to be used depends upon the freezing point of the contaminations. A variety of cold traps are available from Welch-Ilmvac. If the trap is re-warmed it may allow re-evaporation of the condensate. The refrigerant add tube on the liquid nitrogen trap should not be obstructed as the refrigerant boil-off can produce dangerously high pressures.
If the trap becomes saturated it should be disconnected from the system, drained and cleaned. An increase in pressure in the vacuum system will normally indicate that the trap has become saturated. To clean the trap, remove the trap from the system, allow the trap to warm up and rinse off the condensate with a suitable solvent in a fume hood.
Thoroughly clean and dry the trap before reinstalling in the system. Before attaching the pump to a system it is well to familiarize yourself with the function and action of the pump which you have now required.
Remove the intake and exhaust port plugs and temporarily provide a stopper for the intake and a dust cap for the exhaust. Review the power requirements as described in Section 1. The pump will overheat, excessive oil mist will be emitted from the exhaust and the pump will eventually seize. Take every precaution to prevent foreign from entering the pump. Fill the pump until the oil level falls half way of the oil level window.
If after a short period of operation the level should fall, it is likely the result of oil entering some of the interior pockets of the pump. Shut off pump, then drain oil down to proper level. If a gurgling sound occurs, additional oil must be added. Mechanical pumps will gurgle in varying degrees under four conditions of performance: [a] when operating at high pressure as in the beginning cycles of evacuation of a chamber; [b] when the oil level in the pump reservoir is lower than required; [c] when a large leak is present in the system; and [d] when the gas ballast is open.
Awareness of the possibilities will save time in setting up a system. The pump is designed to remove air from a vacuum system at atmospheric pressure to a deep. When the pump is operated at elevated pressures up to about 10 Torr for long periods of time, the pump will run hotter.
At elevated ambient temperatures under these conditions, the thermal protection switch on single phase motors may cut out. Do not run this pump for prolonged periods of time at or above 10 Torr. Quantity: 2. Continue shopping. Product Gallery. Accepted at Checkout. Last 5 Products Reviewed. Vacuum 0.
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