Process Pump

Process Pump
UB series

Wide lineup of back-pullout type including self-priming models

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Technical data

Installation and piping

To make the best use of the features of the UB, UBC types, please follow the items below.


The pump sucks water in the axial direction. Be sure to install an inverse U-bent pipe in the suction piping as shown in the figure below.


The pump, being a self-priming type, does not require installation of a foot valve or an intermediate valve under ordinary operating conditions. However, if frequent operation or shorter self-priming time is desired, we recommend installing such valves. The purpose is to keep as much water as possible in the pump. The valve need not function perfectly and minor leakage will not affect performance.


If a gland packing is used for shaft sealing, we recommend installation of an external flusher to prevent air from being sucked during self-priming and to maintain efficiency of the gland packing.


When the pump is started up, the water inside the casing is discharged once into the discharge side before returning to the casing, and then stabilizes after recirculation begins. If the discharged water floods the check valve and the bent pipe, the amount of recirculating water becomes insufficient and self-priming efficiency decreases. Therefore, be sure to install a riser of the height shown in the figure below. For situations where the riser is too long for installation, we can provide a short discharge pipe (h2) which is made of the same material as the casing and has a special construction. Please contact us for more details.


Be sure to install a check valve on the discharge side of the pump. We recommend the YOKOTA Non-Water Hammer Check Valve to prevent water hammer due to reverse flow when pump operation is stopped. Particularly with parallel operation, when one pump is stopped, it will be subject to back pressure from the other pump, causing water hammer. The YOKOTA Non-Water Hammer Check Valve can prevent water hammer even in such a situation. Further, attachment of the YOKOTA No-Feed Detector (Optional) can prevent the pump from dry operation.


If the pumps are under parallel operation or if the actual pump head above the check valve exceeds more than 1/3 of the shut off head, back pressure acts on the check valve, making it difficult to exhaust air. Install an exhaust valve to relieve such a situation. In this case, install a suitable socket (refer to the table below) on the riser at the highest possible position (refer to "J" in the figure below), and then install the exhaust valve so that the opening end of its suction part is in the center of the riser bore.
There may be water leakage from the exhaust valve. To prevent air from being sucked when operation is stopped, install a pipe from the exhaust valve to a point below the water level of the suction side.
For slurry liquid pumping, please contact us.

Piping layout example 1.
Self-priming suction operation

Attach the inverse U-bent pipe to the pump.

Process Pump / Self-priming suction operation

Limit the extension of the inverse U-bent pipe (L) within 3m.

Process Pump / Self-priming suction operation

Piping layout example 2.
Sealed tank (vacuum tank) extraction operation

Piping layout example 3.
Self-priming suction operation with long horizontal pipe

Attach the inverse U-bent pipe.

Process Pump / Sealed (vacuum) tank extraction operation Operation

Process Pump / Self-priming suction operation with long horizontal pipe horizontal pipe

Length of riser

Process Pump / Length of riser

Length of riser

h1 >= 200 + d + 5H (Total head of pump <= 50m)

h1 >= 300 + d + 5H (Total head of pump > 50m)



Length of riser (mm)


Discharge bore (mm)


Total head of pump (m)

UBO-0523 80mm/50mm x 0.3m3/min x 22m x 1750min-1 x 3.7kW
1 >= 200 + (50) + (5x22) = 360
Use a riser of over 360mm length, desirably over 500mm.
For slurry liquid pumping, please contact us.

Exhaust valve

Discharge pipe bore (mm)

Valve bore

40 - 80








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