Constant Flow Regulator Valve

Constant Flow Regulator Valve
UF series (PAT.)

Easy flow rate setting and outstanding constant flow characteristics

ENEX'92

Received the prize for
outstanding product at the
'92 Energy Saving Exhibition

Patented in Japan, U.S.A., other

Bore	25-600mm
Rated pressure	1MPa

>Selection & Dimensions

Definitive model of constant flow regulator with variable flow rate setting

	Excellent constant flow characteristics
	With the built-in control function, the designated flow rate can be maintained automatically regardless of changes in primary pressure, and the flow rate can be set easily with the handle. It is an excellent variable constant flow regulator.
	Extremely low operating torque
	Due to the unique balancing mechanism, the flow rate setting operation can be done with low torque regardless of water supply pressure. This enables application of a small electric actuator instead of manual operation, and even makes economical application of a solar-powered system possible.
	Simple direct-operation regulator valve
	This simple direct-operation regulator valve does not use complicated pilot valves and is therefore clog-resistant.
	Cavitation characteristics
	Due to the unique pressure reducing mechanism, the allowable cavitation coefficient can be set extremely low.
	Flow rate control characteristics
	Lift type construction of the built-in adjustment valve enables nearly linear performance in flow rate control.
	High-performance
	This automatic regulator valve has both constant flow control and flow rate adjustment functions, so it is easy to handle and suitable for various applications. To ensure durability and reliability, the main parts are made of corrosion and wear resistant materials.
	Demonstrated performance
	Excellent performance as verified by the National Research Institute of Agricultural Engineering of Japan.

Structure & Principle (PAT.)

1.	By adjusting the opening of the adjustment valve disk with the handle, the required flow rate is set. Inlet pressure (primary pressure) P1 is adjusted to intermediate pressure Pd by the throttle resistance in passage A.
2.	Inlet pressure P1 acts on the top of the diaphragm via the primary pressure pipe, and pushes down the sliding valve.
3.	From the lower side, intermediate pressure Pd and working force of the coil spring push up the sliding valve until it is balanced. Then it forms passage B and outlet pressure P2 is created by convergence.
4.	When inlet pressure P1 rises, the transmission of pressure P1, which acts on the top of the diaphragm, pushes down the sliding valve. The sliding valve throttles passage B automatically until the sliding valve can regain balance against intermediate pressure Pd and the force of the coil spring, so that the discharge amount is automatically controlled. According to this principle, the sliding valve is operated only by the differential pressure between P1 and Pd as generated by the opening of the set adjustment valve, and therefore the flow becomes constant at a rate proportional to the adjustment valve opening regardless of the fluctuation of inlet pressure P1 or outlet pressure P2 as caused by the pressure fluctuation in the pipeline.
5.	When the adjustment valve is nearly closed, the adjustment valve disk and the sliding valve disk are integrated via a shaft. Then pressure P1 against the adjustment valve disk from underneath balances with pressure P1 against the diaphragm from above. This makes operation of the handle lighter and facilitates the planning of mechatronics using a low-powered actuator.

Constant flow rate characteristics

		Fig.1
Flow rate stays at a constant value regardless of inlet pressure (primary pressure) P1, outlet pressure (secondary pressure) P2, and their fluctuation. Fig.1 shows the valve's ability to maintain a highly accurate constant flow by following the adjustment valve disk opening {S denotes opening (stroke %) in Fig.1}, regardless of the large variation of P1 and P2, or the large fluctuation of differential pressure (P1-P2). Further, with the linear characteristic (refer to Fig.2), the valve is not influenced by various pipe conditions during operation, and works with good control response and wide control range.		Constant flow rate characteristics at each set flow rate S (adjustment valve opening %)

Flow rate control characteristics

		Fig.2
The YOKOTA Constant Flow Regulator Valve has a lift type construction, which shows superb characteristics as a flow rate adjustment valve. Fig.2 shows performance close to the ideal linear characteristic parallel to a 45 degree diagonal line.

Cavitation characteristics

		Fig.3
The allowable cavitation coefficients (cc) for the YOKOTA Constant Flow Regulator Valve are: With a bore less than 100mm: cc=0.45 With a bore more than 150mm: cc=0.24 As a result, the range in which the valve can be used safely, including the allowable differential pressure range, can be set extremely wide as shown in Fig.3.

Fluctuation of inlet pressure and constant flow rate characteristics

Fig.4

Example applications

For agricultural irrigation

>"Current Topics: Agricultural Water Distribution"

Water distribution to open channel
In-line type, Discharge type

Water distribution to farm pond

For industrial use

Funnel flushing system

Water treatment system

For construction

Large scale local heat supply system

For waterworks

Harbor water supply facility

YOKOTA's proposal for economical piping units

Cost reduction in piping units is possible by using the YOKOTA Constant Flow Regulator Valve.
For example, when supplying cooling water to the engines at rainwater drainage plants, a piping system with an electric ball valve unit and a constant flow valve unit set in a series is generally used.
But, it is possible to simplify this system into a single unit by using the YOKOTA Constant Flow Regulator Valve.
This is because the YOKOTA Constant Flow Regulator Valve not only has a function to control constant flow, but also functions to adjust the required flow rate from the outside and to shut off the flow.
(Example) Comparison with a conventional system when cooling 1050HP engines.
(Calculated by the user)
1. Cost: Approx. 50% reduction
2. Space for installation: Approx. 50% reduction
3. Adjustment of flow rate is possible at installation site

Constant Flow Regulator Valve

Piping examples

Installation in horizontal piping is standard. Please contact us about installation in vertical piping.
1.	Standard piping example
	(1)	It is not necessary to install a straight pipe at the rear of the Constant Flow Regulator Valve. When install a gate valve at the front of the Constant Flow Regulator Valve, install a straight pipe as shown. If you plan to install a flow meter, please install the designated straight pipe.	D=Nominal bore
	(2)	Install a piping within an angle of +/-3 degrees.
2.	When there is a bent pipe on the inlet side:
	(1)	When the bent pipe is parallel to the valve shaft: It is not necessary to install a straight pipe at the front or the rear of the valve.
	(2)	When the bent pipe is perpendicular to the valve shaft: Install a straight pipe as shown.	D=Nominal bore

UF series lineup / Selection charts & Outer dimensions

Type Flange standard	Usage examples Bore (Nominal bore A)	Material Valve case/ Main parts	Drive method
UFS type In-line type JIS 10K, Waterworks standard	Distribution and supply of agricultural, waterworks, industrial and river water Bore 50-600mm	SCS/SCS FC/SCS	Manual Electric actuator (∗) Solar power (∗)
UFT type Upward discharge type JIS 10K, Waterworks standard	Distribution and supply of agricultural, waterworks, industrial and river water Bore 50-150mm	SCS/SCS FC/SCS	Manual
UFF type In-line type JIS 10K FF	Waterworks, air conditioning, local heat supply system, and liquid for industrial use Bore 25-50mm	SCS/SCS	Manual Electric actuator (∗)
UFN type In-line type JIS 10K FF	Waterworks, air conditioning, local heat supply system, and liquid for industrial use Bore 65-150mm	SCS/SCS FC/SCS	Manual Electric actuator (∗)

Note:
	(∗) denotes optional accessories.
	For details of electric actuator drive and solar power drive, please refer to this page.
	Constructions of UFF type and UFN type differ slightly.
	We also manufacture valves with other bore or primary pressure not listed above upon request. Also a wide variety of materials are available, such as YOKOTA's duplex type stainless steel YST130N with high corrosion resistance. Please inquire.
	For special liquids, please contact us.
	Flange dimensions are based on JIS standard.