5
Precautions
1. Precautions for system design
Warning
1. Confirm the specifications.
- Give careful consideration to operating conditions such as the application, fluid and environment,
and use the product within the operating ranges specified in this catalog.
- The product is provided for physical, chemical and industrial equipment.
2. Fluids
- For the compatibility between the materials composing the product and the fluids, check the
compatibility check list. Since the compatibility of the fluid used may vary depending on its type,
additives, concentration, temperature, etc., give sufficient consideration when selecting the
material.
- For fluids other than those listed on the check list, please consult us. Also, use them within the
range of the operating fluid temperatures.
- If foreign matters are mixed in the fluid, these may cause abrasion of the inside of the pump
resulting in a problem. Use an appropriate filter (strainer) to remove them. In general, 80 to 100
mesh (150 to 180 μm) filters are recommended.
- When transferring a coagulable liquid, take measures to prevent it from coagulating in the pump.
- Precautions to observe when transferring slurry
Basically, it is not recommended to transfer slurry because this will result in seating failure and
wearing of the check valve and accumulation of particles. However, if you intend to increase the
number of maintenance cycles even though this promotes wear and accumulation of particles,
use a suction lift of no more than 1 m and also a slurry containing solid particles of the following
diameter.
If the specific gravity of the slurry is less than 3, use particles that have a diameter of no more
than ø0.25 mm and have been passed through a #60 or finer mesh (e.g. aluminum powder).
If the specific gravity of the slurry is 3 or more, use particles that have a diameter of no more
than ø0.15 mm and have been passed through a #100 or finer mesh (e.g. iron powder)
- Take countermeasures to prevent the operating fluid from getting onto the body of the process
pump.
3. Water hammer
If a valve is operated abruptly etc., a high pressure may be applied due to water hammer. Take
measures to prevent pressures higher than specified from being applied.
<Examples of measures>
- Use a water hammer resistant valve to reduce the valve closing speed.
- Use an elastic piping material such as rubber hose or an accumulator to absorb the impact
pressure.
4. Liquid seals
To ensure that fluid does not become sealed inside the process pump, when
stopping the pump, relieve the discharge pressure inside it. As shown in the
figure at right, make a circuit which has a relief valve installed on the
system.
5. Fluid pressure supplied to the process pump
Feeding the fluid from the suction side into the pump under pressure, or
drawing it using a negative pressure, will reduce the life of the pump.
6. Ensure space for maintenance.
Secure the space required for maintenance and inspection. Take into consideration also leakage
from the product. When transferring a flammable liquid or a liquid that may affect the human body
or environment, take measures including fire ban and keeping the area off limits.
7. Use a design which prevents reverse pressure and reverse flow.
If reverse pressure or reverse flow occurs on the discharge side of the process pump, the
equipment is liable to become damaged or malfunction. Take safety measures in designing the
circuit.
8. Measures against static electricity
Take measures against static electricity as static electricity may occur depending on the fluid.
Particularly, when circulating flammable fluid through the pump, be sure to take measures to
prevent the occurrence of static electricity.
