Welch's 2522, 2545, 2534 User Manual

OWNER’S MANUAL

WOB•L® PISTON

PRESSURE/VACUUM PUMPS

MODELS 2522, 2534 AND 2545

Contents: Safety Information

Installation
Operation
Maintenance
Trouble-Shooting Guide
Specifications
Warranty
Parts List and Exploded View

FOR

CE

Warning! Not recommended for pumping acid, base or organic

vapors or gases.

Warning! Be sure to properly identify intake and discharge before

using pump.

SEE Section II-5

Welch Rietschle Thomas

7301 North Central Avenue

Skokie, IL 60077

Phone: [phone]

Part No. 67-0767 Printed in the U.S.A.

Fax: [phone]

Revision A 6/99

Welch Vacuum Technology

Read and understand the following information and
instructions included with your Welch Dry Dual Function
Pressure &Vacuum Pumps before using. This information is
for your safety and to prevent damage to the pumps.

I. SAFETY INFORMATION

I-1. CAUTION TO PREVENT INJURY...

I-1a. 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 Welch service center for examination and
repair.

I-1b. Keep the cord away from heated surfaces.

I-1c. 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.

I-1d. Never drop or insert fingers or any other object into any

openings.

I-1e. Do not operate this product where oxygen is being

administered.

I-1f. This pump is thermally protected and can automatically

restart when the protector resets. Always disconnect
power source before servicing.

I-1g. Wear safety glasses or goggles when operating this

product.

I-1h. Use only in well ventilated areas.

I-1i. Do not use any tools or attachments without first

determining maximum air pressure for that tool or
attachment.

I-1j. Never point any air nozzle or air sprayer toward another

person or any part of the body.

I-1k. All electrical products generate heat. To avoid serious

burns never touch unit during or immediately after
operation.

I-1l. Be sure to properly identify intake and discharge before

using pump. See Section II-5.

I-2. CAUTION: TO REDUCE RISK OF

ELECTRICAL SHOCK…

l-2a. Do not disassemble. Disassembly or attempted repairs

if accomplished incorrectly can create electrical shock
hazard. Refer servicing to qualified service agencies
only.

l-2b. Unit is supplied with a three pronged plug Be sure to

connect pump to a properly grounded outlet only.

I-3. WARNING: TO REDUCE RISK OF

ELECTROCUTION…

I-3a. Do not use this product in or near area where it can fall

or be pulled into water or other liquids.

I-3b. Do not reach for this product if it has fallen into liquid.

Unplug immediately.

I-3c. Never operate this product outdoors in the rain or in a

wet area.

I-4. DANGER: TO REDUCE RISK

OF EXPLOSION OR FIRE…

I-4a. Do not use this pump in or near explosive atmospheres

or where aerosol (spray) products are being used.

I-4b. Do not pump anything other than atmospheric air.

1-4c. Do not pump combustible liquids or vapors with this

product or use in or near an area where flammable or
explosive liquids or vapors may exist.

I-4d. Do not use this product near flames.

FAILURE TO OBSERVE THE ABOVE
SAFETY PRECAUTIONS COULD RESULT
IN SEVERE BODILY INJURY, INCLUDING
DEATH IN EXTREME CASES.

II. INSTALLATION

Il-1. INTRODUCTION

This manual has been compiled not only for the care and
maintenance of the Welch Dry Dual Function Pressure/Vacuum
pump now in your possession, but as a helpful reference and guide
to prevent many problems which can occur if used improperly.

II-2. UNPACKING

Carefully remove the Pressure/Vacuum pump from the shipping
case and unfasten and remove the wooden skid. Preserve all
paperwork for future reference. If damage has occurred from
shipment a claim must be filed with the carrier immediately;
preserve the shipping carton for inspection by the carrier. If you
are required to communicate with your dealer or Welch Vacuum,
be sure to include your order numbers for quick identification.
Do not return the pump to the factory without first calling for a
returned goods number.

Il-3. PUMP MOUNTING

Rubber feet are attached to the pump. Rubber feet are excellent
for applications involving a semi-flexible surface such as a bench
top; they help to isolate noise and eliminate creeping. All Pressure/
Vacuum pumps should he mounted on a horizontal plane.

II-4. PUMP LOCATION

The pressure/vacuum pump should be located preferably in a
clean, dry, and well ventilated area. Please be sure not to block
the ventilation holes located on the motor housing. 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. Welch recommends that the pump be installed at the
highest point within the system to prevent possible water
condensate from entering the pump. The pump should be located
as closely to its system in order to utilize it most efficiently.

Warning! The motor is thermally protected and
will automatically restart unexpectedly when
the overload device resets. Don’t pump
flammable or explosive gases or vapors or
operate this pump in an atmosphere containing
flammable or explosive gases or vapors.

II-5. INTAKE AND DISCHARGE PROVISIONS

Two regulators and two gauges make it easy to meet your vacuum
and pressure requirements. The vacuum regulator and vacuum
dial gauge is attached to the intake port. The vacuum regulator
allows the vacuum level to be set between roughly atmospheric
pressure and the maximum vacuum allowed for the pump model.
A moisture trap keeps water from accidentally being drawn into
the unit.

The pressure regulator and pressure dial gauges are attached to the
discharge port. The pressure regulator allows discharge pressure to
be set between atmospheric and the maximum possible for the pump
model. Discharge air is filtered and noise is muffled with a filter.

Note: Adjusting either the pressure or vacuum regulators will

affect the performance of the pump.

PROPERLY IDENTIFY THE INTAKE AND

DISCHARGE OF THE PUMP

Intake Discharge

reference point for the pressure gauge is atmospheric pressure.

Please keep in mind that atmospheric pressure tends to vary from
day to day. As a result of this variability, the dial vacuum gauge
will indicate slightly different maximum vacuum readings from
day to day.

II-9. TRAPS

II-9a. The need for a Trap

The pumps will handle humid air. All wetted aluminum parts are
treated for corrosion protection from moisture. All other wetted
parts are stainless steel. A plastic trap with a ball check valve is
attached to the regulator assembly to prevent water condensate from
accidentally being ingested into the pump. If there is a chance liquid
may be drawn from the process under evacuation, Welch
recommends a liquid trap be placed between the process and the
pump. A simple liquid trap is a filtering flask. See figure below.

Discharge

Pressure/Vacuum Pump

WARNING!: Never Block The Discharge Port.
If the exhaust is blocked, pressure will build- up
in the pump above its rated operating pressure.

Be sure to call Welch technical service prior to start-up at (847)
676-8800 if you have any questions.

II-6. ELECTRICAL POWER

lI-6a. Power Source Review

Review the power source and the motor rating to be sure they agree
in voltage, phase, and frequency. Serious damage may occur to the
motor if it is connected to an improper voltage. All Welch pumps
must be grounded. Grounding reduces the risk of electric shock in
the event of an electrical short circuit. The plug must be plugged
into a properly grounded outlet. Consult your local electrical codes
if you have doubts.

ll-6b. Overload Protection.

Motor thermal overload protection is made available by the motor
manufacturer as an aid to minimize motor failure.

Overload protection is a standard feature on both 50 and 60 Hz
single-phase-motors. The motors have automatic overload
protection. 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.

II-7. VACUUM CONNECTIONS

All pressure/vacuum pumps come with intake and discharge hose
barbs which accept 1/4" ID rubber pressure/vacuum hose. Hose
clamps should be used to hold the hose in place. Since all three
models operate in the viscous flow regime, 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 chamber be kept as small as possible.

II-8. VACUUM AND PRESSURE GAUGES

All models of pressure/vacuum pumps come with dial gauges
mounted on the regulator assemblies. The vacuum gauge gives
negative pressure - that is pressure below atmospheric. The reference
point for the vacuum gauge is atmospheric pressure.

The pressure gauge gives pressure above atmospheric. The

Suction

Filtration Manifold Liquid Trap

When a heavy load of water vapor is evolved from the vacuum
process, a cold trap is recommended to help prevent damage to the
pump mechanism. The cold trap, immersed in a suitable Dewar
flask, is installed so that the water vapors may come in contact
with the surfaces of the trap and condense. Commonly used
refrigerants are liquid nitrogen or dry ice and acetone or alcohol.
Dry ice provides sufficient cooling to freeze out most heavy water
vapor loads. A variety of cold traps are available from Welch. Please
call our customer service department for additional information at
[phone].

WARNING!: The pump is not recommended for
pumping acid, base or organic vapors or gases.
Serious damage to the pump will shorten the
pump’s service life. In addition, pumping
flammable vapors or gases can lead to serious
safety hazard leading to fire or explosion.

lI-9b. 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 rewarmed 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 pro- duce
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 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 into the system.

Ill. OPERATION

Ill-1. STARTING PROCEDURES