Welch Vacuum 1397 User Manual

WELCH-ILMVAC

OWNER’S MANUAL FOR

DUOSEAL® VACUUM PUMP MODELS:

1374, 1374B-01, 1374B-10, 1374M-01, 1397, 1397B-01, 1397B-10, 1397B-80, 1397C-03, 1397J-01, 1397M-01, 1397W-01, 3Z657

WARNING

Never Block the Exhaust Port

If the exhaust is blocked, pressure will build up in the pump with the potential of the oil reservoir bursting and causing possible injury to personnel in the area

SAVE THESE INSTRUCTIONS
Welch-Ilmvac
5621 W. Howard Street
Niles, IL 60714
Phone: [phone] (Technical Support)
Fax: [phone]
E-Mail: [e-mail]	Part No. 67-2076
Web-Page: www.welchvacuum.com	Printed in USA

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 the 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 processes

These units conform to the SI Inernational system of units of measurement.

The folowing symbols (with recommendations of IEC1010) of warning will be found on the pump.

Caution - refer to accompanying documents

Caution - hot surface

Caution - risk of electrical shock

WARNING

Motor includes a self-resetting thermal cut-out and the pump could restart without actuation under falt condition

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	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 - Dimensional 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

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SECTION 1: INSTALLATION

1.10Introduction

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.

1.11Unpacking

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 filed 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 identification. Do not return the pump to the factory without firstcompleting the on-line request form for returned goods authorization at www.welchvacuum.com.

1.12Pump 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-flexible 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 firm 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.

1.13Pump 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. Aboveall, the pump should be located as closely as possible to its system in order to utilize it most efficiently. Its location should include such determining factors as the length and size of connections, the number of bends and the type of exhaust connections.

1.14Exhaust 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 flows are involved or where the presence of oil vapor is objectionable an exhaust filter may be fastened to the exhaust port in place of the dust cap. The exhaust filters 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.

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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 fitting 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 flow of gas. This is particularly true at low pressures in the millitorr range where the gas flow is substantially molecular in character. The gas flow 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 fittings 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 flow, the valve openings should be as large as possible. Lubricate the rotating plug of the stopcock with a film of vacuum grease sufficiently thick enough to prevent seizure.

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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 flask, 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 Vacuum, Thomas Industries, inc.

1.172 The care of a Trap

When using a cold trap the refrigerant should be maintained at a high level in the flask 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

2.10Starting 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 fine 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 efficient and satisfactory performance should be determined after the pump has reached its operating temperature. Initially, however, the pump should be filled 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 signifies 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 sufficient time has been allowed for the pump to come to operating temperature.

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2.20Operation and System Optimization

2.21High Pressure Operation

DUOSEAL two-stage pumps are designed to be most efficient 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 filter 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 at 847-676-8800 for further information and precautions.

2.22 Principle of Gas Ballast

2.221 Effects of Unwanted Vapor

Systems which contain undesirable vapors cause difficulty both from the standpoint of attaining desirable ultimate pressures as well as contamination of the lubricating medium. A vapor is defined 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 emulsified 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 finally expelled form the pump as a vapor.

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2.225 Controlled Ballast Flow

Some degree of variation in ballast flow may be obtained by the amount of opening applied tot he gas ballast. Two or more turns of the gas ballast are sufficient 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.

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 flammable!

2.233 Fine Leaks

Locating very fine leaks requires a helium-sensitive, mass-spectrometer leak detector. This instrument will locate leaks which cannot be detected by any other method. Numerous fine 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, first 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 refill with a fresh charge.

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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 efficiency 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 efficiency in a mechanical pump is contamination of oil. It is caused by condensation of vapors and by foreign particles. The undesirable condensate emulsifies 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 efficient 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.

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

3.20Oil 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 flush of DUOSEAL pumps be performed at the regular maintenance oil change. The procedure for the forced oil flush is given below.

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