1400
WELCH-
I
L
MV
A
C
OWNER’S MANUAL FOR
DUOSEAL® VACUUM PUMP MODELS:
1400B-01 & 3Z654
WARNING
Never block the Exhaust Port.
If the exhaust port is blocked, pressure will build-up in the pump
with the potential of the pump body bursting and causing possible
injury to personnel in the area.
Part No. 67-2065 R1.0
Printed in USA
Welch-Ilmvac
5621 W. Howard Street
Niles, IL 60714
Phone: (847) 676-8800 (Technical Support)
Fax: (847) 677-8606
E-Mail: gdwelchvacuum@gardnerdenver.com
Web-Page: www.welchvacuum.com
2
INSTRUCTION
WARNING AND CAUTION
PLEASE READ BEFORE OPERATION
While reading your manual, please pay close attention to areas labeled:
WARNING AND CAUTION.
The description of each is found below.
WARNING
Warnings are given where failure to observe instruction could
result in injury or death to people.
CAUTION
Cautions are found where failure to observe the instruction could
result in damage to the equipment, associated equipment and
process.
These units conform to the SI International system of units of measurement.
The following symbols (with recommendation of IEC1010 ) of warning will be found on the pump.
Caution - Refer to accompanying documents
Caution - Risk of electrical shock
Caution - Hot surface
WARNING
Motor includes a self resetting thermal cutout and the pump could
restart without actuation under fault condition.
3
TABLE OF CONTENTS
Section Page
Section 01 - Installation
1.10 Introduction 4
Section 02 - Operation
2.10 Starting Procedures 6
2.20 Operation and System Optimization 6
2.21 High Pressure Operation 7
2.22 Gas Ballast Principles and Usage 7
2.23 System Leaks - Impact and Detection 8
2.30 Shutdown Procedure 8
Section 03 - Maintenance
3.10 Vacuum Problems 9
3.20 Oil Changes and Oil Level 10
3.30 Shaft Seal Replacement 10
3.40 Repairing Oil Leaks 11
3.50 Repairing Vacuum Leaks 11
3.60 Drive Problems 11
Section 04 - Trouble Shooting Guide
4.10 Poor Vacuum Readings 12
4.20 Noisy Pump 12
4.30 Excessive Oil Mist 12
Section 05 - Quick Reference Chart
Chart 1 13
Chart 2 13
Section 06 - Dimenional Drawings (with rotation)
Vacuum Pump 14
Section 07 - Pumping Speed Curves
Speed Curves 15
Section 08 - Exploded Views and Parts Lists
Vacuum Pump 16
Oil Case 18
Section 09 - Accessory Section
Chart 1 19
Chart 2 20
Section 10 - MSDS - Sheets for DUOSEAL® OIL
MSDS-Sheet for 1407K 21-27
4
Section 1: INSTALLATION
1.10 Introduction
This manual has been complied not only for the care and maintenance of the DUOSEAL pump now in your
possession but as a helpful reference and guide for many problems which are usually associated with mechanical
vacuum pumps. Take time to read these instructions carefully and preserve this manual for future reference; we
think it will be useful to you.
1.11 Unpacking
Carefully remove the pump from the shipping case and unfasten and remove the wooden skid. Preserve all
paper work and inspection tags for future reference. If damage has occurred from shipment a claim must
be fi led with the carrier immediately; preserve the shipping container for inspection by the carrier. If you are
required to communicate with your dealer or with Welch Vacuum be sure to include your order numbers for quick
identifi cation. Do not return the pump to the factory without fi rst completing the on-line request form for returned
goods authorization at www.welchvacuum.com.
1.12 Pump Mounting
1.121 Mounted Pumps
Rubber bumpers are supplied with most of our mounted pumps, either loosely or attached. Bumpers are
excellent for applications involving a semi-fl exible surface such as a bench top; they help to isolate noise and
eliminate creeping. For more rigid requirements, the pump base may be bolted directly to a fi rm foundation with
or without the bumpers. All DUOSEAL pumps should be mounted in a horizontal plane.
1.122 Unmounted Pumps
If you have purchased an unmounted pump, refer to parts list for information concerning the motor, motor pulley
and belt necessary to drive your particular pump at the recommended speed.
1.13 Pump Location
The pump should be located preferably in a clean and well ventilated area and adequate space should
be provided wherever possible for routine maintenance such as changes of oil and belt adjustments and
replacements. Above all, the pump should be located as closely as possible to its system in order to utilize it most
effi ciently. Its location should include such determining factors as the length and size of connections, the number
of bends and the type of exhaust connections.
1.14 Exhaust Provisions (See Accessory section in back of this manual.)
Exhaust connections will be determined by the type of system to be exhausted and the desired cleanliness of
the atmosphere surrounding the pump. Under normal conditions of mild evacuation nothing more than the dust
cap will be necessary to cover the port. Where relatively high gas fl ows are involved or where the presence of oil
vapor is objectionable an exhaust fi lter may be fastened to the exhaust port in place of the dust cap. The exhaust
fi lters used on our pumps are capable of absorbing and restricting any vapor particle larger than 0.1 micron.
WARNING
Never block the Exhaust Port. If the exhaust port is blocked,
pressure will build-up in the pump with the potential of the pump
body bursting and causing possible injury to personnel in the area.
Where extreme exhaust conditions are encountered it is best to pipe the exhaust direct out of the building. Welch
recommended wire reinforced PVC, metal pipe or thick walled rubber hose be used as exhaust lines to avoid
potential of line becoming crimped or collapsing resulting in the exhaust port being clocked. Be sure to call Welch
technical service prior to start-up at 847-676-8800 if you have any questions.
5
1.15 Electrical Power
1.151 Power Source Review
Review the power source and the motor rating to be sure they agree in voltage, phase and frequency. On three-
phase 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.
CAUTION
Make certain the power settings on the pump match your power
source before attempting to operate the pump
1.152 Overload Protection
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. Motors of 1-1/2 horsepower or larger supplied with DUOSEAL
pumps contain no 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.
1.16 Vacuum Connections (See Accessory Section in back of this manual.)
1.161 Choice of Connections
The choice of connections and fi tting can have a very marked effect on the pumping speed at the vacuum
chamber. Any connection placed between the pump and the chamber creates an impedance to the fl ow of gas.
This is particularly true at low pressures in the millitorr range where the gas fl ow is substantially molecular in
character. The gas fl ow is then dependent upon the kinetic activity of the molecules to bring it to the intake of the
pump.
1.162 The Effects of Conductance
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.
1.163 Metal Joints
If metal piping or tubing is used, it is preferable to solder or braze all of the connections. Where threaded joints
must be used, coat the threads with LocTite® Thread Sealant with PTFE, or Leak Lock and screw together tightly.
Flanged connections with elastomer gaskets make excellent demountable joints. Modular vacuum piping and
fi ttings are now extensively used.
1.164 Rubber Tubing 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.
1.165 Valves and Stopcocks
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. To minimize the impedance of fl ow, the valve openings should be
as large as possible. Lubricate the rotating plug of the stopcock with a fi lm of vacuum grease suffi ciently thick
enough to prevent seizure.
6
1.17 Traps (See Accessory section in the back of this manual.)
1.171 The need for a Trap
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. The cold trap, immersed in a suitable Dewar fl ask, is installed to that the vapors may
come in contact with the surfaces of the trap and condense. 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.
1.172 The care of a Trap
When using a cold trap the refrigerant should be maintained at a high level in the fl ask to keep the trap at a
uniformly low temperature. 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.
Section 2: OPERATION
2.10 Starting Procedures
2.101 Starting a DUOSEAL Pump
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 1.4.
CAUTION
Do not run this pump with the intake open directly to the
atmosphere. The pump will overheat, excessive oil mist will be
emitted from the exhaust and the pump will eventually seize.
2.103 Cleanliness
Take every precaution to prevent foreign from entering the pump. A fi ne mesh screen is provided for this purpose
in the intake passage of all DUOSEAL pumps.
2.104 Oil Level Determination
The amount of oil suitable for effi cient and satisfactory performance should be determined after the pump has
reached its operating temperature. Initially, however, the pump should be fi lled with fresh oil while the pump is
idle. 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. If the oil level rises,
this signifi es oil has drained into the pump cavity while pump was idle. 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.
Best performance of a mechanical pump is generally obtained after suffi cient time has been allowed for the pump
to come to operating temperature.
7
2.20 Operation and System Optimization
2.21 High Pressure Operation
DUOSEAL two-stage pumps are designed to be most effi cient when operated at or near their ultimate blanked
off pressure. The pump is designed to remove air from a vacuum system at atmospheric pressure to a deep
vacuum. 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. Use of an exhaust fi lter with coalescing element is required.
CAUTION
Do not run this pump for prolonged periods of time at or above 10 Torr. The
pump will overheat, excessive oil mist will be emitted from the exhaust and the
pump will eventually seize.
Leaky vacuum systems, too large a vacuum chamber for pump size or high gas loads to the vacuum systems are
causes for extended runs of the pump at elevated pressure. If you need additional information, please contact
Welch Vacuum at 847-676-8800, extension 1, for further information and precautions.
2.22 Principle of Gas Ballast
2.221 Effects of Unwanted Vapor
Systems which contain undesirable vapors cause diffi culty both from the standpoint of attaining desirable ultimate
pressures as well as contamination of the lubricating medium. A vapor is defi ned as the gaseous form of any
substance which is usually a liquid or a solid. Water, oil and a mercury vapors are three of the more common
vapors encountered in typical vacuum systems. When such vapors exist in a system, the vapors or mixtures of
gas and vapor are subject to condensation within the pump; the precipitated liquid may thus ultimately dissolve or
become emulsifi ed with the lubricating medium. This emulsion is recirculated to the chambers of the pump where
it is again volatilized causing increased pressure within the system.
2.222 Presence and Removal of Condensate
Condensation takes place particularly in the compression stroke of the backing or second stage of a two-stage
pump. The compression stroke is that portion of the cycle during which the gas drawn from the intake port is
compresses to the pressure necessary to expel it past the exhaust valve. Condensation takes place when the
ratio between the initial pressure and the end pressure of the compression is high, that is, when the mixture
of vapor and gas drawn from the intake port is compressed from a low pressure to high pressure. By adding
air though the gas ballast valve to the mixture of vapor and gas being compressed, the pressure required for
delivery past the exhaust valve is reached with a considerably smaller reduction of the volume of the mixture;
this, depending upon the amount of air added, condensation of the vapor is wither entirely avoided or substantial
reduced.
2.223 Pump Function With Gas Ballast
In a pump functioning on a contaminated system and operating without the gas ballast, compression within
the stage takes place in the normal manner until the saturation pressure of the contaminating vapor contained
within the mixture of gas and vapor is reached. The saturation pressure of water vapor is that pressure and
corresponding temperature at which the dew point of the vapor is reached and condensation occurs. The
saturation pressure of water vapor at an ambient temperature of 20°C is 17.5 Torr, while at 60°C, the approximate
operating temperature of a pump, the saturation pressure is 149 Torr. The external side of the exhaust valve
is subjected to atmospheric pressure. Consequently a compressive force somewhat greater than atmospheric
pressure is required to open the valve and permit expulsion of the gas. Sometime during increased compression
of the mixture of gas and vapors, the saturation pressure of 149 Torr for the water vapor is reached and the vapor
condenses. The condensate is then allowed to emulsify with the oil which is recirculated within the pump stages
this providing continued contamination of the system.
2.224 Pump Function With Gas Ballast
On the other hand, when ballast air at atmospheric pressure is supplied to the compression stroke by means of
the gas ballast, the partial pressure of the unwanted vapor becomes a very small part of the total pressure of the
mixture of gas, vapor and newly supplied air. The vapor is thus prevented from reaching its saturation pressure
corresponding to the temperature of the pump and is fi nally expelled form the pump as a vapor.
2.225 Controlled Ballast Flow
Some degree of variation in ballast fl ow may be obtained by the amount of opening applied tot he gas ballast.
Two or more turns of the gas ballast are suffi cient to open it wide. With the gas ballast open, the sound of the
exhaust is similar to that of a pump operating against a large leak. Because of the increased pressure introduced
into the compression stroke, the pump must work a little hard to function, thus resulting in an increased operating
temperature of approximately 8°C over a prolonged period of time. Tests have shown that continuous and
prolonged operation for several weeks under these conditions is not injurious to the pump.
8
2.226 Other Forms of contamination control
The application of the gas ballast is a moderate and very successful method for the removal of
condensable vapors. For very heavily laden systems, other means of removal such as oil separators
may be required. For mild cases of contamination the simple expedient of a cold trap or a change of oil
serve the purpose.
2.23 System Leaks - Impact & Detection
2.231 Large Leaks
The importance of eliminating all leaks in a vacuum system is obvious when it is realized that a leak
into the system, at atmospheric pressure, expands in volume by a factor of 750,000 to 10,000,000
or more. The pump must remove this added volume to maintain the desired vacuum. Fortunately a
number of effective techniques for leak detection have been developed. Large leaks can be located by
pressurizing the system and painting the suspected area with a thick soap solution. Escaping air will
produce soap bubbles.
2.232 Small Leaks
Small leaks may also be detected by spraying a suspected area with acetone or gases rich in
hydrogen, and observing a sudden change in pressure on an electrical gauge. The difference in
calibration of these gauges, for air and other gases, will produce a distinct change in the pressure
reading. To use this method of detection, the system must be under vacuum and the gauge sensing
tube must be located between the pump and the area to be probed. Use extreme caution, as these
materials are highly fl ammable!
2.233 Fine Leaks
Locating very fi ne leaks requires a helium-sensitive, mass-spectrometer leak detector. This instrument
will locate leaks which cannot be detected by any other method. Numerous fi ne leaks can have the
total effect of a large leak.
2.30 Shutdown Procedures
2.301 DuoSeal Shutdown
A few simple precautions are all that is necessary when shutdown is in order. If a gauge is connected
to the system, fi rst isolate the gauge, then turn off the power and open the system to atmosphere. If
the pump is removed from the system, cover the intake port with a rubber stopper or suitable cover to
protect the pump against contamination and loose particles. If the pump has been contaminated in
service and is going to be shelved for a prolonged period it is best to drain the oil and refi ll with a fresh
charge.
9
Section 3: MAINTENANCE
3.10 Vacuum Problems
3.101 Pressure Determinations
Leakage, contamination and unusual outgassing are the general causes of problems associated with
poor vacuum. To operate at maximum effi ciency a system must be thoroughly clean. If the system is
completely clean and free from leaks, and unwarranted vacuum problems still exist, the pump should
be checked. A simple criterion for the condition of a mechanical pump is a determination of its ultimate
pressure capability. This can be accomplished by attaching a gauge directly to the pump. The gauge
may be any suitable type provided consideration if given to the limitations of the gauge being used.
Refer to Paragraph 1-8 for further suggestions. If the pressure is unusually high, the pump may be
badly contaminated, low on oil or malfunctioning. On the other hand, if the pressure is only slightly
higher than the guaranteed pressure of the pump, an oil change may be all that is required.
3.102 Oil Contamination
The most common cause of a loss in effi ciency in a mechanical pump is contamination of oil. It is
caused by condensation of vapors and by foreign particles. The undesirable condensate emulsifi es
with the oil which is recirculated and subject to re-evaporation during the normal cycle of pump activity
thus reducing the ultimate vacuum attainable. Some foreign particles and vapors may form a sludge
with the oil, impair sealing and lubrication and cause eventual seizure. A gas ballast calve is helpful in
removing vapors, especially water, but it is not equally effective on all foreign substances; therefore,
periodic oil changes are necessary to maintain effi cient operation of the system. The required
frequency of changes will vary with the particular system,. Experiences with the process will help you
determine the normal period of operation before an oil change is required.
3.103 Oil Overheating
This pump is designed to operate continuously below 10 Torr. Continuous operation of this pump
above 10 Torr will lead to overheating and eventual pump failure. See Section 2.21, High Pressure
Operation.
WARNING
Solvents, such as acetone, used to clean different pumps are
extremely hazardous. Inhalation may be fatal or harmful. Acetone
is also extremely fl ammable. Never use acetone near heat or open
fl ame. Use only in a well ventilated area.
3.20 Oil Changes and Oil Level
3.201 Developing a Maintenance Schedule
After studying many examples of pump failure, Welch has found the most common reason is poor
condition of the oil. This is why a regular maintenance schedule for the oil is critical to obtain the
longest service life out of your DUOSEAL pump. Welch recommends that you examine the condition
of the oil on a daily basis in the early days of a new process or experiment. You want to look for
discoloration of the oil and whether the oil level is rising. The discoloration can indicate deterioration
of the oil and a rising oil level can indicate condensation of vapors is occurring in the pump. When
changes occur, the oil needs to be change. If no changes in the oil level or color are observed,
extended pump service life is obtained if the oil is changed every three to four months.
3.202 Forced Oil Flushing
When you drain oil through the drain valve, you are not removing the oil and contaminants that are
inside the pumping mechanism. You are removing oil only from the oil case. Welch recommends
a forced oil fl ush of DUOSEAL pumps be performed at the regular maintenance oil change. The
procedure for the forced oil fl ush is given below.
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