Blagdon Pump B75 Руководство по обслуживанию и эксплуатации - Страница 5

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PRINCIPLE OF PUMP OPERATION

This ball type check valve pump is

1:1 ratio design. The inner side of one

diaphragm chamber is alternately

pressurised while simultaneously

exhausting the other inner chamber.

This causes the diaphragms, which are

connected by a common rod secured

by plates to the centres of the

diaphragms, to move in a reciprocating

action. (As one diaphragm performs

the discharge stroke the other

diaphragm is pulled to perform the

suction stroke in the opposite chamber.)

Air pressure is applied over the

entire inner surface of the diaphragm

while liquid is discharged from the

opposite side of the diaphragm. The

diaphragm operates in a balanced

condition during the discharge stroke

which allows the pump to be oper-

ated at discharge heads over 200 feet

(61 metres) of water.

For maximum diaphragm life,

keep the pump as close to the liquid

being pumped as possible. Positive

suction head in excess of 10 feet of

liquid (3.048 metres) may require a

back pressure regulating device to

maximize diaphragm life.

Alternate pressurising and

exhausting of the diaphragm cham-

ber is performed by an externally

mounted, pilot operated, four way

spool type air distribution valve. When

the spool shifts to one end of the

valve body, inlet pressure is applied

to one diaphragm chamber and the

INSTALLATION GUIDE

Top Discharge Ball Unit

Available from

Blagdon Pump

PD75M Pulsation Dampener

020-052-000 Filter/Regulator

020-052-001 Lubricator

020-048-008 Air Dryer

CAUTION

The air exhaust should be

piped to an area for safe

disposition of the product

being pumped, in the event

of a diaphragm failure.

520-319-000 Air Operated Double Diaphragm Pump

other diaphragm chamber exhausts.

When the spool shifts to the opposite

end of the valve body, the pressure

to the chambers is reversed. The air

distribution valve spool is moved by

a internal pilot valve which alternately

pressurises one end of the air distri-

bution valve spool while exhausting

the other end. The pilot valve is

shifted at each end of the diaphragm

stroke when a actuator plunger is

contacted by the diaphragm plate.

This actuator plunger then pushes

the end of the pilot valve spool into

position

activate

the

distribution valve.

The chambers are connected with

manifolds with a suction and

discharge check valve for each

chamber, maintaining flow in one

direction through the pump.

INSTALLATION AND START-UP

Locate the pump as close to the

product being pumped as possible.

Keep the suction line length and

number of fittings to a minimum. Do

not reduce the suction line diameter.

For installations of rigid piping,

short sections of flexible hose should

be installed between the pump and

the piping. The flexible hose reduces

vibration and strain to the pumping

system. A Blagdon PD75M pulsation

dampener is recommended to further

reduce pulsation in flow.

AIR SUPPLY

Air supply pressure cannot

exceed 125 psi (8.6 bar). Connect the

pump air inlet to an air supply of

11/01

sufficient capacity and pressure

required for desired performance.

When the air supply line is solid

piping, use a short length of flexible

hose not less than ½" (13mm) in

diameter between the pump and the

piping to reduce strain to the piping.

The weight of the air supply line, regu-

lators and filters must be supported by

some means other than the air inlet

cap. Failure to provide support for the

piping may result in damage to the

pump. A pressure regulating valve

should be installed to insure air supply

air

pressure does not exceed recom-

mended limits.

AIR VALVE LUBRICATION

The air distribution valve and the

pilot valve are designed to operate

WITHOUT lubrication. This is the

preferred mode of operation. There

may be instances of personal prefer-

ence or poor quality air supplies when

lubrication of the compressed air

supply is required. The pump air

system will operate with properly

lubricated compressed air supply.

Proper lubrication requires the use

of an air line lubricator (available from

Blagdon) set to deliver one drop of

SAE 10 non-detergent oil for every 20

SCFM (9.4 liters/sec.) of air the pump

consumes at the point of operation.

Consult the pump's published

Performance Curve to determine this.

AIR LINE MOISTURE

Water in the compressed air supply

can create problems such as icing or

freezing of the exhaust air, causing the

Pulsation

Dampener

Limited to

125 psi

pump to cycle erratically or stop

operating. Water in the air supply can

be reduced by using a point-of-use air

dryer to supplement the user's air

drying equipment. This device

removes water from the compressed

air supply and alleviates the icing or

freezing problems.

AIR INLET AND PRIMING

To start the pump, open the air

valve approximately ½ to ¾ turn.

After the pump primes, the air valve

can be opened to increase air flow

as desired. If opening the valve

increases cycling rate, but does not

increase the rate of flow, cavitation

has occurred. The valve should be

closed slightly to obtain the most

efficient air flow to pump flow ratio.

BETWEEN USES

When the pump is used for mate-

rials that tend to settle out or solidify

when not in motion, the pump should

be flushed after each use to prevent

damage. (Product remaining in the

pump between uses could dry out or

settle out. This could cause problems

with the diaphragms and check

valves at restart.) In freezing tem-

peratures the pump must be com-

pletely drained between uses in all

cases.

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