INOXPA Regulating Seat Valve NLR


The NLR valve is a proportional pneumatically actuated valve designed for flow control in installations of the dairy and food-processing industries, beverage production, pharmaceutical and fine chemicals industries. The most important applications are pressure control, flow control, tank level, etc.

Operating principle

The position sensor instantly controls the operating position to keep the valve in the position determined by the user (PD function) or by a process parameter (PID function).
The operation position can be programmed by:

– a standard input signal sent by en external element (e.g. a sensor). 4…20mA o de 0 a 10V
– an internal controller integrated into the positioner. The signal is sent form a keyboard.


Design and features

Normally closed valve (standard version).
Equal percentage regulation shaft.
360º adjustable body.
Compact design.

Dual function positioner:

-PD: position controller
-PID: process controller

Easy assembly/disassembly by loosening the clamp.
Standard connections: weld.



Parts in contact with the product                                        AISI 316L
Other stainless steel parts                                                     AISI 304
Gaskets                                                                                      EPDM according to FDA 177.2600
Internal surface finish                                                            Ra ≤ 0,8 μm
External surface finish                                                           bright polish



Steam barrier (if shaft sterilisation is required).
Jacketed body.
Larger actuator sizes.
Internal surface finish Ra ≤ 0,5 μm.
Gaskets: NBR or FPM.
Connections: DIN, Clamp, SMS, RJT, FIL-IDF, etc.


Technical specifications


In the case of the pressure regulation, it is necessary to indicate the range of the pressure to regulate (inlet/outlet pressure) and the valve inlet flow. In the case of the flow regulation, it is necessary to indicate the flow range to regulate (valve outlet) and the valve inlet pressure. The NLR is an equal percentage flow characteristic valve. The Kv factor is usually used to calculate the dimensions of this kind of valves, the factor allow us to relate the pressure drop and the flow. The Kv factor is defined as the flow of water through a valve in cubic meters per hour with a pressure drop of 1 bar (see table below).

The Kv is calculated for water at 5-30ºC.

The required Kv (Kv ) for products with low viscosity and density can be calculated by means of this formula:
Kv = Q/√ΔP (for viscous products, consult the technical department).

Q (required flow in m³/h)
ΔP (pressure drop in bar: inlet pressure minus outlet pressure)

The selected Kv (Kv ) index must be higher than the required Kv to ensure a sifficient margin for control.
Thus, a safety factor is applied by means of the formula: Kv = Kv / 0,7.

Q= 15 m³/h ΔP = 1 bar
Kv = Q/√ΔP = 15
Kv = Kv / 0,7 = 21,43


For calculation in other units: Cv = 1.16 x Kv (gallon/minute and psi)
NB: Remember that the NLR valve is not a shut-off valve and its code includes neither positioner nor potentiometer.