Summarized questions from customers.

1. Self-priming pumps 　　2. End suction pump 　　3. Submersible pump 　　4. Centrifugal sealless pumps
5. General FAQ 　　6. Oil collecting systems

Is a foot valve required on the suction side?

No. (But this applies only for the suction lift pump as describe in the catalog.) The self-priming pump of WORLD CHEMICAL has a mechanism that retains sufficient amount of priming water for the next run once priming water is filled. If you use a foot valve with surfactant mixed liquid that generates large amount of foam, it may cause the self-priming operation to malfunction by blocking the air outflow when the self-priming started.

What are the precautions when installing or removing the pump?

First, please read the safety precautions in the instruction manual before proceeding with the installation or removal. For installation, please be sure to take out the “Protection Seal” on the suction/discharge openings. For removal, please turn off the main power first. Then, disconnect cables and close the piping valve on inflow/outflow side. Remove liquid through the drain cock and dismount the pump. Please be careful not to splash liquid.

I ran the pump without filling up the priming water first. I soon realized and turned off the pump. Was I able to avoid the damage? Does the pump work OK?

The pump may be damaged from dry running. Please contact the distributor and obtain more information by providing the pump type and product serial number.
　　

I turned on the pump, but pumping doesn’t start. There is a sufficient amount of liquid on the suction side, and the pipe diameter is in the proper size. I checked the rotating direction and didn’t recognize any error. What would be the reason why pumping doesn’t start?

Among several possible reasons, the pump may have some air trapped inside. If the air removal system is installed on the discharge pipe, please use the system to remove the air and fill priming water in the casing. Or by repeatedly turning the pump ON and OFF (start and stop) a few times, it may move the air so that priming water fills in the casing. If no air removal system is installed but the check valve is installed on the discharge pipe, please install the air removal system between the check valve and casing discharge opening. And when switching pumps, please be sure to remove the air and check if priming water is filled before operating the pump.

Some foreign substances may have been stuck, and the pump making abnormal noise. Will removing the foreign substances clear the noise?

Even though you remove the foreign substances, they may have damaged inside of the pump by abrasion. Please contact the distributor and report the problem.
　　

Can I use the submersible pump for high concentrated strong acid or strong alkaline liquid?

The submersible pump cannot be used for certain kinds of liquid. Please contact the distributor to verify what kind of liquid the pump can be used for by providing the liquid information (name of the liquid, concentration, specific gravity, temperature, etc.).

Is there a submersible pump with single-phase 100V specification?

No. We only offer a single specification with 3-phase 200V, 1.1kW motor.

I’d like to replace some parts. Are disassembly and reassembly quite simple?

They will require several complicated procedures, such as centering the unit, adjusting the impeller clearance. We recommend the parts replacement done by our technicians.

The pump has a heavy vibration, and discharge volume seems much less than it is supposed to be. What are the reasons?

Cavitation may be occurred because the pump cannot maintain inadequate liquid inflows through the suction pipe. Please check the following and remove possible causes: if crystal or other substances are stuck in the suction pipe, if the strainer is installed and clogged with crystal or other substances, or if there is air entrainment by the occurrence of vortex flow caused by low liquid level on the suction side.

Liquid leakage occurs to NSF-type pump when turned off.

Temporary liquid leakage may be occurred by a large amount of residual water at the time of shutdown. NSF has a mechanism that keeps some priming water (residual water) for the next run when it stops. When the flow speed of backwater from the discharge pipe to inside of the pump is faster than the one from inside of the pump to the pit, temporary liquid leakage may occur to the lower part of the pump because some of the backwater cannot go anywhere but flows into the upper part of the pump. In addition, temporary liquid leakage may also occur when the foot valve is installed: the valve blocks the backwater moving from inside of the pump to the pit, and more than acceptable amount of liquid inside of the pump flows back through the discharge pipe.

When NSF-type pump was first installed, no liquid leakage was recognized. But recently, liquid started leaking. Why is this happening?

It may be happening because the seal effect is worn out as rubber elasticity of gas seal is weakened causing inflexibility. Or the liquid leakage may be caused by the reasons described in 3 items above. NSF is equipped with dry seal that seals gas and prevents motor corrosion caused by liquid gas. The dry seal has high sealability to prevent rising gas or external leakage of gas, but not to seal liquid. When the pump is first installed, dry seal has some rubber elasticity and may be effective to seal liquid. As rubber elasticity gets weakened by chemical attack, aged deterioration, etc., however, dry seal can no more seal liquid. * The main function of dry seal is to seal gas, not to seal liquid. If liquid pressure is generated, please use NSF-type with built-in linear seal. Or for self-priming and End suction pump, please select GV-type (horizontal self-priming magnetic pump).

Do you offer any product lineups connected with thread type or union type other than flanges type?

Yes, several pump types we offer, such as small-size magnetic pumps, has some lineups. Please contact the distributor for more information.

Are pumps equipped with dry running prevention mechanism?

No, pumps are not equipped with dry running prevention mechanism. We offer “dry running prevention system” that detects abnormal current value and forcibly disconnects electrical circuit related to pump activation. This system is sold separately, so please contact the distributor for more information.

What is the maximum liquid temperature the pumps can resist?

Each pump has different upper temperature limit. And corrosion resistance of pump varies depending on the relationship between chemical concentration and temperature. So please contact the distributor and obtain more information by proving the pump type and use application.

Is the corrosion resistance chart available?

Yes. However, the main purpose of the corrosion resistance chart is to provide reference information to select a proper pump. The chart shows corrosion resistance of pumps under restricted conditions but does not provide any guarantee on those results.

Can you quote liquid requirements/conditions by PH value?

No. We will need more information besides PH value. Corrosion resistance on connection part varies depending on liquid type, concentration and temperature. Even though different liquid types have the same PH value, they may not be able to use the same resin. When you inquire for quotation, please provide information on liquid type, temperature and specific gravity in addition to PH value.

Can oil be collected from emulsioned liquid (turbid liquid, mixture of water and oil) using the system?

Oil collecting system and separator of WORLD CHEMICAL operate using the difference in specific gravity of water and oil. The system can transfer emulsioned liquid, however, it cannot separate oil from emulsioned liquid in such a short time (only a few minutes) that our standard separator uses as separation time.

The system does not seem to be separating much oil as it is supposed to be. What are possible causes?

It could be caused by various reasons depending on situations. Please contact the distributor and provide detailed information on the situation because it will often be very helpful to determine the cause.

Can the system collect foreign substances or waste other than oil?

Basically, the system can. As actual examples, the system performed for collecting scum at sewage plants and collecting blue-green algae in lakes.

How much can the system separate oil and water?

Depending on the liquid condition, the separating efficiency is an average of 80%.

What are the differences between GYROSYSTEM and GREASECOMING?

Both GYROSYSTEM and GREASECOMING have the common fundamental mechanism that the pump draws in floating substances on water surface through the gate ring on the float, and the separator separates the substances using the difference in specific gravity. But the differences are in their structures: GYROSKIMMER standardizes the equipment of the submersible pump; GREASECOMING is a float suction type that standardizes the installation on land. Though, both offer special types.
　　　
Examples of use for GYROSYSTEM:GYROSYSTEM is equipped with a secure submersible pump and can be performed for liquid that is mixed with relatively large amount of slurry. It also can transfer liquid from deep pits in which self-priming pumps cannot operate. GYROSYSTEM is perfect for emergency oil spill collection in central coolant tanks, rivers or harbors.
　　　
Examples of use for GREASECOMING:The suction pump is installed on land and assembled with positive displacement self-priming pump (Moyno type, vane type, monoflex type). It can be used for various types of floating substances, such as oil with relatively high viscosity (food oil, etc.), mineral oil or scum.

In regard to the corrosion resistance of GYROSKIMMER, can it be placed in acid or alkaline liquid?

No, it cannot be placed in acid or alkaline liquid. The submersible pump, frame or other parts installed on GYROSKIMMER is not resistant to neither acid nor alkaline liquid.

What is the upper temperature limit of this system?

The maximum temperature for standard type of GYROSKIMMER and GREASECOMING is 40. The minimum is the temperature range before floating oil becomes solidified. Washing saver can be used repeatedly until it reaches the maximum of 95. Please contact the seller for detailed information.

What are the reasons why the collecting system has lower collection flow rate compare to other companies’ systems?

It is because our system has higher collection efficiency. Collection flow rate and collection rate are not the same. Collecting only the thin layer of floating oil will deliver higher collection efficiency as it floats in thin surface layer. On the other hand, collecting thick layer will cause higher ratio of fluid other than oil and lower collection rate. The patented double float technology of WORLD CHEMICAL efficiently collects wide-spread floating oil in surface layer. Other companies’ systems has higher collection rate just because they only collect thick surface layer, not thin surface layer.