Welch Vacuum 2028 User Manual

WELCH-IL

MV

A

C

OWNER’S MANUAL

FOR

SELF-CLEANING DRY VACUUM SYSTEM™

MODELS: 2025, 2026, 2027 & 2028

2025 2027 2028

(9 Torr, 12 mbar) (2 Torr, 2.7 mbar) (2 Torr, 2.7 mbar)

2026

(2 Torr, 2.7 mbar)
Improved to better meet your laboratory needs.

- New electronics with an enhanced self-cleaning feature to help extend diaphragm life

- Superior vacuum level regulator for setting vacuum pressures

- Improved corrosion resistant housing and front panel

- Protective jar cover to help protect inlet and outlet jars

WARNING

Be sure to properly identify intake and discharge

before using pump. See Section 2.14

CAUTION

Do not pump liquids with the pump.

Pumping liquids will cause the pump to stop working.

Welch-Ilmvac
5621 W. Howard Street
Niles, IL 60714
Phone: [phone] (Technical Support)
Fax: [phone]
E-Mail: [e-mail]
Web-Page: www.welchvacuum.com

Part No. 642835

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 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 confi rm 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.

2

TABLE OF CONTENTS

SECTIONS PAGE
Section 01 - Safety Information

1.10 To Prevent Injury 04

1.20 To Reduce Risk of Electrical Shock 04

1.30 To Reduce Risk of Electrocution 04

1.40 To Reduce Risk of Explosion or Fire 04
Section 02 - Installation

2.10 Introduction 05

2.20 Electrical Power 06

2.30 Traps 07
Section 03 - Component, System and Unit Operations

3.10 Component Description 09

3.20 Control Locations 09

3.30 Vacuum Gauge / System Control Function 10

3.40 Vacuum Level Regulation 16

3.50 Gas Ballast Valve 16

3.60 Rapid Response Vacuum Adjustment 16

3.70 Inlet and Exhaust Separators 17

3.80 Unit Start Procedure and Operation 17
Section 04 - Maintenance

4.10 General Maintenance 18
Section 05 - Calibration

5.10 Calibration for Model 2027 only 18
Section 06 - Troubleshooting

6.10 Vacuum Problems 20
Section 07 - Specifi cation

7.10 Pump Specifi cation Table 23
Section 08 - Drawings, Parts List and Exploded View

8.10 Dimensional Drawing 24

8.11 Schematic Wiring Diagram for Models 2025 and 2026 24

8.12 Schematic Wiring Diagram for Model 2027 25

8.13 Schematic Wiring Diagram for Model 2028 25

8.14 Parts List and Exploded View for Dry Vacuum System 27

8.15 Parts List and Exploded View for Repair Kits 28
Section 09 - Warranty 29

3

Section 1: SAFETY INFORMATION

1.10 To prevent injury....

1.11 Never operate this product if it has a damaged cord or plug. If it is not working properly, has been
dropped, damaged or has fallen into water, please return the product to a Gardner Denver Welch Vacuum
Technology service center for examination and repair.

1.12 Keep the cord away from the heated surfaces.

1.13 Never block any air openings or place it on a soft surface where the openings may be blocked. The air
openings are for ventilation of the motor inside the housing. Keep all air openings free of lint, dirt and
other foreign objects.

1.14 The PTFE pump is thermally protected and can automatically restart when the protector resets. Always
disconnect power source before servicing.

1.15 Wear safety glasses or goggles when operating this product.

1.16 Use only in well ventilated areas. The motor is fan cooled enclosed in a shell.

WARNING

Do not operate the pumps in an atmosphere

containing fl ammable or explosive gases/vapors.

WARNING

Never block the exhaust port. If the exhaust is blocked, pressure

will build-up in the pump with the potential of the pump head

bursting and causing possible injury to personnel in the area.

1.17 All electrical products generate heat. To avoid serious burns never touch unit during or immediately after
operation.

1.18 Be sure to properly identify intake and discharge before using pump. See Section 2.14.

WARNING
Remove plug(s) from Exhaust Port(s). The Self cleaning Dry Vacuum
System has one outlet port and one inlet port. The ports are labeled.

1.20 To reduce risk of electrical shock....

1.21 Do not disassemble. Disassembly or attempted repairs if accomplished incorrectly can create electrical
shock hazard. Refer servicing to qualifi ed service agencies only: Contact your closest Gardner Denver
Welch Vacuum Technology sales offi ce. See directory on back cover.

1.22 Unit is supplied with a three pronged plug. Be sure to connect pump to a properly grounded outlet only.

1.30 To reduce risk of electrocution…

1.31 Do not use this product in or near area where it can fall or be pulled into water or other liquids.

1.32 Do not reach for this product if it has fallen into liquid. Unplug immediately.

1.33 Never operate this product outdoors in the rain or in a wet area.

1.40 To reduce risk of explosion or fi re…

1.41 Do not use this pump near explosive atmospheres or where aerosol (spray) products are being used.

1.41 Do not use this product near fl ames.

WARNING

Failure to observe the above safety precautions could result

in severe bodily injury, including death in extreme cases.

4

Section 2: INSTALLATION

2.10 Introduction

This manual has been compiled not only for the care and maintenance of the Welch Dry Vacuum System

now in your possession, but as a helpful reference and guide to prevent many problems which can occur
if used improperly.

2.11 Unpacking

Carefully remove the Dry Vacuum System from the shipping carton. Preserve all paperwork for future

reference. If damage has occurred from shipment a claim must be fi led with the carrier immediately;
preserve the shipping carton for inspection by the carrier. If you are required to communicate with your
dealer or Welch-Ilmvac be sure to include your order numbers for quick identifi cation. Do not return the
system to the factory without fi rst calling for a returned goods number. Contact your closest Welch-Ilmvac
sales offi ce.

2.12 System Mounting

Rubber feet are attached to the pump. Rubber feet are excellent for applications involving a semi-fl exible

surface such as a bench top; they help to isolate noise and eliminate creeping. The Self-Cleaning Dry
Vacuum System must be positioned with the feet on a fl at surface.

2.13 System Location

The Self-Cleaning Dry Vacuum System should be located preferably in a clean, dry and well ventilated

area. Please be sure not to block the ventilation ports located on the metal shell. The pump should be
placed where the surrounding temperature remains between 10°C and 40°C (50°F and 104°F). Always
check to insure the location chosen is protected from direct or indirect moisture contact. The pump should
be located as closely to its system in order to utilize it most effi ciently.

WARNING

Don’t operate this pump in an atmosphere containing fl ammable or explosive

gases or vapors.

CAUTION

If operating the unit in a hood, be aware of other hood uses and users – always

avoid activities that could compromise unit function. For example, an acid

digestion in the hood with the pump system will destroy unit electronics.

WARNING

Do not position the equipment so that it is diffi cult to operate the disconnecting

device. (Removal of the plug or power cord from the socket outlet).

2.14 Inlet and Outlet Provisions

An inlet hose barb which accepts ¼” (7mm) I.D. hose makes it easy to connect the system to your

concentrator, rotary evaporator or gel dryer. Since the vacuum system operates in the viscous fl ow
range, the small diameter of the hose will generate minimal conductance loss. For best results, Welch
recommends the length of the tubing between the pump and the apparatus be kept as short as possible.
Hose clamps should be used to hold the hose in place. The hose barb in the outlet port of the pump
accepts ¼” (7mm) I.D. hose. A vent line can be attached to the outlet hose barb which allows gases
and vapors pumped through the pump to be piped to a fume hood. If you any questions, be sure to call
technical service prior to start-up. Contact your closest Gardner Denver Welch Vacuum Technology sales
offi ce.

WARNING

Never Block The Outer Port. If the outlet is blocked, pressure will buildup in

the pump which can lead to the pump head bursting creating the potential of

serious injury. Remove plug from outer port.

5

PROPERLY IDENTIFY THE INLET AND OUTLET OF THE PUMP

Outlet Port

Inlet Port

WARNING:
(Model 2028 shown) Remove Plug From Exhaust
Port Before Operating.

2.20 Electrical Power

2.21 Power Source Review

Review the power source and the voltage rating on the units serial number tag to be sure they agree in

voltage, phase and frequency. Serious damage may occur to the system if it is connected to an improper
voltage. All Welch systems must be grounded. Grounding reduces the risk of electric shock in the event
of an electrical short circuit. The plug must be plugged into an outlet properly grounded. Consult your
local electrical codes if you have doubts.

2.22 Identifi cation Symbols

OFF (Power) on Models: on Model:

ON (Power) 2025, 2026 & 2027 2028

2.23 Grounding Instructions

This product should be grounded. In the event of an electrical short circuit, grounding reduces the risk of

electric shock by providing an escape wire for the electric current. This product is equipped with a cord
having a grounding wire with a grounding plug. The plug must be plugged into an outlet that is properly
installed and grounded in accordance with all local codes and ordinances.

WARNING

Improper installation of the grounding plug

can result in a risk of electrical shock.

If repair or replacement of the cord or plug is necessary, do not connect the grounding wire to either

fl at blade terminal. The wire with insulation having an outer surface that is green with or without yellow
stripes is the grounding wire.

Check with a qualifi ed electrician or serviceman if the grounding instructions are not completely

understood, or if in doubt as to whether the product is properly grounded. Do not modify the plug
provided; if it will not fi t the outlet, have the proper outlet installed by a qualifi ed electrician.

Model’s 202501, 202601, 202701 and 202801 are for use on a nominal 120V circuit, and has a grounding

plug that looks like the plug illustrated in Sketch A in Figure #1. A temporary adapter, which looks like
the adapter illustrated in sketches B and C, may be used to connect this plug to a 2-pole receptacle as
shown in sketch B if a properly grounded outlet is not available.

6

The temporary adapter should be used only until a properly grounded outlet (Sketch A) can be installed

by a qualifi ed electrician. When using the temporary adapter, the green colored rigid ear, lug, etc.
extending from the adapter must be connected to a permanent ground such as a properly grounded
outlet box cover. Whenever the adapter is used, it must be held in place by a metal screw.

2.24 Extension Cords

If necessary to use an extension cord, use a 3-wire extension cord that has a 3-blade grounding plug,

and a 3-slot receptacle that will accept the plug on the product. Make certain your extension cord is
in good condition. Make certain your extension cord wire size is not less than 18 gauge for 25 feet,
16 gauge for 50 feet, and 14 gauge for 100 feet. An undersized cord will cause a drop in line voltage
resulting in loss of power and overheating. If in doubt, use the next heavier cord. The smaller the gauge
number, the heavier the cord. Avoid routing the extension cord through areas that could result in damage
to the cord.

2.30 Traps

2.31 When To Use A Trap

The Self-Cleaning Dry Vacuum System is constructed of PTFE or fl uorinated plastics on all wetted

surfaces to resists chemical attack from aggressive solvent, base and acid vapors. A totally oil free
diaphragm mechanism removes the need for lubricating and sealing fl uids for pulling a vacuum. When
pumping gases or low vapor loads, a trap is not necessary unless you want to capture vapors evolved
from the process. When a heavy load of water or organic vapor is evolved from the vacuum process,
condensation of vapor in the pump mechanism may occur. The reason is the pump is compressing
the vapor as it passes through the pump. If the vapor is dense enough, the compression will cause
condensation of the vapor in the pump mechanism. The valve system in the pump mechanism is
designed to pass the small quantity of liquefi ed vapor formed when pumping heavy vapor loads. The
liquid formed will be ejected from the outlet port. The self-cleaning purge feature of the Self-Cleaning Dry
Vacuum System is designed to eject condensed vapors left in the pump up on shut-done.

The advantage of a cold trap when pumping heavy vapor loads is that it will increase the effective

pumping speed of the Self-Cleaning Dry Vacuum System. The trap acts as an additional pumping
mechanism, increasing the effective pumping speed. This higher effective pumping speed will shorten
the time needed to strip solvent. The time savings will depend on such factors as the solvent stripped,
solvent temperature and operating temperature of the cold trap.

The cold trap is installed between the pump and the vacuum chamber. The water or organic vapors

evolved from the vacuum process entering the cold trap will come in contact with the cold surfaces of the
trap and condense. Commonly used refrigerants are liquid nitrogen or dry ice with alcohol slurry. Dry
ice provides suffi cient cooling to freeze out most heavy water vapor loads. A variety of cold traps are
available from Welch. Visit the Welch Web-Site at www.welchvacuum.com.

2.32 Solvent Traps

Your Self-Cleaning Dry Vacuum System comes with a basic solvent removal capability to remove

readily condensable solvents prior to pump ingestion and to collect solvent accumulated during pump
condensation and the Self-Cleaning cycle. Solvent removal can be further enhanced to provide additional
pumping effi cacy, safety, solvent fate control, and pump life. Depending upon your application, additional
solvent trapping may be desirable. Solvent trapping confi gurations are discussed below; consult your
Welch representative for application specifi c trapping recommendations.

2.33 Self-Cleaning Dry Vacuum System Solvent Removal

When pumping gases or low vapor loads, a trap is not necessary unless you want to capture vapors

evolved from the process. When a heavy load of water or organic vapor is evolved from the vacuum
process, condensation of vapor in the pump mechanism may occur due to compression. The valve
system in the pump mechanism is designed to pass a small quantity of liquefi ed vapor formed when
pumping heavy vapor loads. The liquid formed will be ejected from the outlet port. The self-cleaning
purge feature of the Self-Cleaning Dry Vacuum System is designed to eject condensed vapors left in the
pump upon shut-down and collect condensate in the side-mounted jar.

7

2.34 Cold Trap Solvent Removal

Condensation of organic solvent fumes is typically accomplished by suspending a trap in a Dewar fl ask

containing dry ice / isopropanol slurry or liquid nitrogen. Alternatively low maintenance cooling to -100oC
can be achieved using a refrigerated cold trap. The cold trap is connected between the application and
the pump unit to prevent solvent ingestion. Installation of a cold trap when pumping heavy vapor loads
offers several advantages:

• The Self-Cleaning Dry Vacuum System will operate more effi ciently. The trap acts as an additional
pumping mechanism, increasing the effective pumping speed. This higher effective pumping speed will
shorten the time needed to strip solvent.

• The absence of a high solvent load in the pump diaphragm mechanism promotes pumping effi ciency
and extends diaphragm life.

• Vacuum pump pass-through of solvents is reduced, preventing possible discharge into the laboratory
atmosphere and enabling responsible control of chemical usage and potential solvent recycling. A variety
of cold traps are available from Welch. Contact your closest Gardner Denver Welch Vacuum Technology
sales offi ce or visit the Welch Web-Site at www.welchvacuum.com.

2.35 CAPTURE

TM

Cold trap

Your Welch Self-Cleaning Dry Vacuum System can be extended to include a CAPTURETM cold trap.

This trap is a pump-mounted condenser utilizing recirculating chilled water can be confi gured to remove
solvent fumes from the vacuum stream either prior to the pump inlet to lessen solvent ingestion or on
the pump outlet to reduce emissions. The CAPTURE

trap provides continuous solvent condensation
without the need to recharge a cold trap with dry ice / isopropanol or liquid nitrogen. Contact your Welch
representative for more CAPTURE information or see www.welchvacuum.com

2.36 The Care of a Liquid Trap
A liquid trap needs no refrigerant. The key maintenance issue when pumping high vapor loads is to

regularly drain the trap of liquid ejected from the dry vacuum pump.

2.37 The Care of a Cold 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 rewarmed it may allow re-evaporation of the condensate. 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 and 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 the system. If a
liquid nitrogen trap is used, the refrigerant add tube on the liquid nitrogen trap should not be obstructed
as the refrigerant boil-off can produce dangerously high pressures.

2.38 Application Note for Cold Trap
Cold traps employing a dry ice slurry or liquid nitrogen are effective as long as the refrigerant level

is maintained. If the trap warms up while the pump is running, all of the trapped condensable will be
ingested by the vacuum pump. Cold traps must be cleaned out at the end of each day. If the pump is
run overnight, the trapped condensable will ultimately be ingested by the pump as the trap warms up.
Cleaning a Dry Ice Slurry/Liquid Nitrogen trap is easy. The steps are:

1. Turn off the pump.

2. Leak air into the trap.

3. Remove the center well and Plexiglas ring to a hood. The center well can be washed off into a
beaker or the condensable can be allowed to evaporate in the hood.

8

Section 3: COMPONENTS, SYSTEM AND UNIT OPERATION

3.10 Components

- 3.20 Control Locations

- 3.21 Control Locations for Models 2025, 2026 and 2027

- 3.22 Control Locations for Model 2028

- 3.30 Vacuum Gauge / System Function

- 3.31 Vacuum Gauges for Models 2025 and 2026

- 3.32 Vacuum Gauge / System Control Function for Model 2027

- 3.33 Vacuum Gauge / System Control Function for Model 2028

- 3.40 Vacuum Level Regulation

- 3.50 Gas Ballast

- 3.60 Rapid Response Vacuum Adjustment

- 3.70 Inlet and Outlet Separators (all Models)

3.20 Control Locations

3.21 Control Locations for Models 2025, 2026 and 2027

VACUUM CONTROL KNOB
GAS BALLAST SWITCH
POWER

3.22 Control Locations for Model 2028

MANUAL VENT
AUTO Anti BUMPING/FOAMING
MENU MAXIMUM VACUUM
NUMERIC KEY PAD UP/DOWN ARROWS
VACUUM CONTROL POWER

KNOB
Push to select menu options

9