Diaphragm Pumps (Air Operated Double Diaphragms)
Diaphragm Pumps are air or natural gas operated displacement pumps
which uniquely differ from all other positive displacement pumps.
As a result of air pressure acting on the entire surface of the
diaphragm, the diaphragm is in a balanced condition while pumping.
This measurably extends diaphragm life over that of mechanically
operated diaphragm pumps.
Because compressed air is limited, the maximum pressure is also
safely limited. This pumps are appropriately selected for on-demand
intermittent requirements or continuous duty.
Pumps are available with a wide choice of construction materials
and accessories for any industrial.
We want to become the preferred partner of manufacturer leaders
whenever they need the most reliable, fast and globally spread
service for the maintenance of their machinery. Diaphragm Pumps
We are one of the top suppliers in the original spare parts sector;
based in China, we have been working in the fluid field for many
years and we can take advantage of our proximity to the industry
district. We are able to supply any kind of parts simply by working
with the machine manufacturer codes (part numbers). We currently
serve Customers all over the world. Diaphragm Pumps
Specific knowledge of the products marketed.
Competences in order to advise the customer the machine that’s
right for his needs.
Clarity and seriousness in business relationships with customers,
suppliers and employees.
We think we are a reliable partner for the fluid industries.
We are always updated with the latest technology and requests.
Reliability, credibility and reputation has meant that every
customer has found us in a serious and reliable to turn to for
We offer our customers the most comprehensive range of spare parts,
becoming the sole interlocutor of the purchasing department, with
measurable savings in terms of time and costs.
Installation operation and maintenance:
READ, UNDERSTAND, AND FOLLOW THIS INFORMATION TO AVOID INJURY AND
Do not exceed the maximum inlet air pressure as stated on the pump
- The air inlet of the pump is connected to the air supply that has
sufficient capacity and of which pressure conforms to the design
- The clean compressed air makes for the extension of the service
life of the pump.
- If the air supply line is a hard pipe, the short hose connecting
the pump and the pipe can reduce vibration and twisting. (It is
recommended to reduce the pulse in the fluid with a use a surge
tank or fluid buffers.)
- The air intake pipe and the pressure-regulating filter must be
supported due to their weight. If the pipe is not supported, it may
damage the pump.
- The air intake pipe of the pump must be installed with the pressure
regulating valve to ensure the air supply pressure doesn’t exceed
the specified range.
The limit pressure specified in the Manual can’t be used in the
operation of the pump, otherwise the personal injury, pump damage
or property loss will arise out of excessive air pressure.
- Be sure material hoses and other components are able to with -stand
fluid pressures developed by this pump. Check all hoses for damage
or wear. Be certain dispensing device is clean and in proper
STATIC SPARK. Can cause explosion resulting in severe injury or
death. Ground pump and pumping system.
- Sparks can ignite flammable material and vapors.
- Secure pump, connections and all contact points to avoid vibration
and generation of contact or static spark.
- Use proper ventilation.
- Keep inflammables away from heat, open flames and sparks.
- Keep containers closed when not in use.
The discharges from the pump may contain impurities, which may
cause serious injury. The discharges can be drained away through
the pipe from the jobsite and around the operator.
Even if the diaphragm ruptures, it can also discharge the material
forcibly from the exhaust muffler.
- When the hazardous or inflammable materials are pumped, the
discharges can be removed to the safe remote location through the
- Between the pump and the muffler is used the interface of 3/8” in
HAZARDOUS PRESSURE. Can result in serious injury or property
damage. Do not service or clean pump, hoses or dispensing valve
while the system is pressurized. Disconnect air supply line and
relieve pressure from the sys -tem by opening dispensing valve or
device and / or carefully and slowly loosening and removing outlet
hose or piping from pump.
HAZARDOUS MATERIALS. Can cause serious in -jury or property damage.
Do not attempt to return a pump to the factory or service center
that contains hazardous material. Safe handling practices must
comply with local and national laws and safety code requirements.
- Obtain Material Safety Data Sheets on all materials from the
supplier for proper handling instructions.
Explosion Hazard: Some models, together with some parts that fluid
contacts, are made of aluminum, so they can’t be put into use with
trichloroethane, methylene chloride or other halogenated
hydrocarbon solvents, otherwise they may react and cause an
- Prior to the use with this type of solvent, it is a must to inspect
the fluid caps, manifolds and all fluid contact parts of the pump
motor in order to ensure compatibility.
- The pump should be placed close to the product as far as possible
to shorten the suction pipe and reduce the number of parts to the
- To extend the service life of diaphragm, we must to place the pump
close to the pumped fluid as much as possible. When the inlet
pressure exceeds 10 feet (3 meters) of the fluid column, it is
necessary to install a set of pressure relief and regulation
devices to extend the service life of diaphragm.
- We must ensure the sealing of each adapter for the inlet and outlet
- All the fasteners must be tightened once again prior to the use of
the Product to avoid the looseness that may arise out of the creep
of the seal components and effectively prevent the leakage of fluid
Verify the chemical compatibility of the pump wetted parts and the
substance being pumped, flushed or re -circulated. Chemical
compatibility may change with tempera -ture and concentration of
the chemical(s) within the substances being pumped, flushed or
circulated. For specific fluid compatibility, consult the chemical
Maximum temperatures are based on mechani -cal stress only. Certain
chemicals will significantly reduce maximum safe operating
temperature. Consult the chemical manufacturer for chemical
compatibility and temperature lim -its.
Make sure that all the operators of this equipment have been
specifically trained, grasped the safe operating practices and
understood the limitations of the equipment. They know how to wear
PPE if needed.
Do not use the pump for the structural support of the piping
system. Be certain the system components are properly supported to
prevent stress on the pump part
- Suction and discharge connections should be flexible connec -tions
(such as hose), not rigid piped, and should be compatible with the
substance being pumped.
It is a must to prevent unnecessary damage to the pump. If it has
to lie idle for a long time, please clean it thoroughly after each
- The Product left in the pump will become dry or sticky on the pump,
which will give rise to the diaphragm and valve problems prior to
the next start. At the freezing temperature, it is must to empty
the pump completely under any circumstances after use.
- It is an effective way in reducing users’ downtime to get the
appropriate assembly available at any time. The application of the
authentic BSK spare parts will be conducive to the extension of
product life and the play of the performance.
The BSK diaphragm pump offers high volume delivery even at low air
pressure and a b road range of material compatibility options
available.Refer to the model and option chart.The BSK pump is
provided with the modularized air motor and fluid section.
The air operated diaphragm pump alternately generates the intake
fluid pressure and positive fluid pressure in the fluid chamber by
using the pressure difference in the air chamber. The ball valve
can ensure the forward flow of fluid.
Pump cycling will begin as air pressure is applied and it will
continue to pump and keep up with the demand. It will build and
maintain line pres -sure and will stop cycling once maximum line
pressure is reached (dis -pensing device closed) and will resume
pumping as needed.
Requirements for Air and Lubrication
EXCESSIVE AIR PRESSURE. Can cause pump damage, personal injury or
- A filter capable of filtering out particles larger than 50 microns
should be used on the air supply. There is no lubrication required
other than the “O” ring lubricant which is applied during assembly
- If lubricated air is present, make sure that it is compatible with
the “O” rings and seals in the air motor section of the pump.
- Always flush the pump with a solvent compatible with the material
being pumped if the material being pumped is subject to “setting
up” when not in use for a period of time.
- Disconnect the air supply from the pump if it is to be inactive for
a few hours.
- The outlet material volume is governed not only by the air supply
but also by the material supply available at the inlet. The
material supply tubing should not be too small or restrictive. Be
sure not to use hose which might collapse.
- When the diaphragm pump is used in a forced -feed (flooded inlet)
situation, it is recommended that a “Check Valve” be installed at
the air inlet.
- Secure the diaphragm pump legs to a suitable surface to insure
against damage by vibration.
- Please refer to the component schematic in the assembly drawings to
look up the serial numbers and names of parts and grasp the
information of parts and maintenance service pack.
- Some BSK parts are marked as "wearing parts", which can conduce to
quick service and downtime reduction.
- Service kits are divided to service two separate diaphragm pump
functions: 1. AIR SECTION, 2. FLUID SECTION. The FLUID SEC -TION is
divided further to match typical part MATERIAL OPTIONS.
- Provide a clean work surface to protect sensitive internal moving
parts from contamination from dirt and foreign matter during
service disassembly and reassembly.
- Keep good records of service activity and include pump in preven
-tive maintenance program.
- Before disassembling, empty captured material in the outlet man
-ifold by turning the pump upside down to drain material from the
FLUID SECTION DISASSEMBLY
- Remove the upper and lower manifold (1) and (11).
- Remove the ball (2), “O” ring (3) (47) and ball seat (4).
- Remove the fluid cap (5).
NOTE: Only diaphragm models use a primary diaphragm(6A) and a
backup diaphragm(6). Refer to the aux iliary view in the Fluid
- Remove the screw (10), washer (9), diaphragm (6A, 6) and diaphragm
washer (7, 8).
NOTE: Do not scratch or mar the surface of (23) diaphragm rod.
FLUID SECTION REASSEMBLY
- Reassemble in reverse order.
- Clean and inspect all parts. Replace worn or damaged parts with new
parts as required.
- Lubricate (23) diaphragm rod and 25) “Y” ring with grease.
- Fix the diaphragm rod (23) with the auxiliary installation tool.
- Prior to the final fastening of bolts and nuts, please determine
whether the diaphragm (6A,6) is aligned with the fluid cap (5)
properly to avoid the twisting of the diaphragm.
- For the models using Teflon diaphragm: three rubber diaphragms (6)
on the side, which are marked with AIRS SIDE "air chamber" are
mounted in face of the pump body.
- Start the pump, check the fastening and sealing after it runs for a
period of time.
Disassembly of the Parts in Fluid Section
a)First, remove the pump from the pipeline system and drain off the
materials from the pump inside. b)Place the pump in a clean work
environment. c)Dismantle the outlet pipe (1) from the pump first,
and then take out the ball (2), O cup (3) and (47) and ball seat
(4) from the upper end of the fluid cap (5) in sequence. After
that, place the pump upside down and dismantle the inlet pipe (11)
so as to take out O cup (3) and (47), ball seat (4) and ball (2)
from the fluid cap (5). d)Release the bolts around the two fluid
caps to disassemble the cap (5). e)Release the diaphragm screw (10)
and remove diaphragm washer (7), (8) and diaphragm (6) from the
both ends. Remove the diaphragm rod (23) and the lip-shape seal
ring (25) can be replaced. Disassembly of Parts for Air Valve
f)Loosen the bolt (39) first, and then dismantle the air valve
casing (38), air baffle (42) and sealing gasket (40), and (41). g)
Take out the valve slice (36) and valve plate (37) from the air
valve casing (38). h) Dismantle the circlip (29) and take out the
limit end cap (31) from both ends of the air valve casing (38), and
you can replace the cup (30) as needed. i)You can check the
lip-type packing (33) after pushing out the spool (35) from the air
valve casing (38) with the hands. Disassembly of Parts for Pilot
Valve j) Loosen 4 bolts (16) fixing the cylinder head first, and
then dismantle the cylinder head (14) and (18) on both ends and
remove the O cup (17). k) Remove the sealing gasket (19) from the
groove of the motor casing (15). l) Eject the pilot rod (22) and
trigger rod (45) from the motor casing (15) and you can replace the
lip-type packing (20) on the trigger rod or the O cup (44) on the
pilot rod. Reassembly of Diaphragm Pump The reassembly steps of the
pump are incompatible with those of disassembly, so you are kindly
asked to pay attention to the following in the reassembly process:
1) All the sealing elements, as well as their contact parts, must
be greased. 2) Please check carefully prior to the use of all
sealing elements whether they are damaged, such as surface damage.
If damaged, please replace the new ones. 3) The lip direction of
the lip-type packing (20)(, 25) and (33) should be consistent with
the direction shown in the chart. 4) The bolts on the fluid cap
should alternately be fastened by opposite angles to achieve a
better sealing result. Troubleshooting 1. Some fluid is drained
from the exhaust opening along with the air flow. Check the
diaphragm for any damage. Check the diaphragm screw for looseness
2. There are Air bubbles in the outlet fluid Check the suction pipe
connection for good sealing. Check the connection between the
suction pipe and the intake manifold for good sealing. Check the O
ring between the intake manifold and the fluid cap Check the
diaphragm screws for looseness 3. Low pump output Check the air
supply is stable. Check the inlet/outlet for any blockage. Check
connectors connecting the intake manifold for air tightness Check
that the ball is not stuck to the seat or the ball is not
improperly seated. 4. Air is discharged from the exhaust opening
when there is no reciprocating movement. Check seal ring (33) on
slid valve (35). Check seal ring (20) on trigger rod (45). Check
seal ring (25) on diaphragm link rod