Pneumatic Globe Control Valve

Model: PLV-21

PLV-21 is a globe control valve based on a pneumatic diaphragm actuator. It accommodates sizes from 1/2 inch (15A) to 20 inches (500A) and offers a wide range of specifications tailored to process conditions, including ANSI 150#-2500#, JIS 10K-40K, and PN10-40 pressure ratings; Equal Percentage, Linear, and Quick Open flow characteristics; and Unbalanced/Balanced plug options.

Features

Pneumatic Globe Control Valve PLV-21

Specifications

TYPE & MODELGLOBE CONTROL / LVB-21 Series
SIZE1/2” (15A) ~ 20” (500A)
BODY MATERIALSCPH2, WC6, SCPH21, WC9, SCPH22, C12A, SCPH23 ,CF8, CF8M, CF3, CF3M
TRIM MATERIALSUS304, SUS316, SUS316L, 304+HF, 316+HF, 316L+HF, 304+SFL, 304+STELLITE, 316+STELLITE
PRESSURE RATINGJIS 10K, 20K, 30K, 40K, ANSI 150#, 300#, 600#, 900#, 1500#, 2500#, PN10, PN16, PN25, PN40
FLANGE END CONNECTIONRF, RTJ, SW, BW, Thread
BONNETStandard, Extension, Fin, Bellows, Long Extension (Cryogenic)
FLOW CHARACTERISTICEqual Percentage, Linear, Quick Open
LEAKAGEANSI CLASS Ⅳ (Metal Seat), CLASS Ⅴ (Soft Seat)
PLUG TYPEUnbalanced, Balanced
ACTUATOR TYPEDiaphragm, Pneumatic Cylinder
VALVE ACTIONReverse action, Direct action
RANGEABILITY20:1, 30:1, 50:1, 100:1

Frequently Asked Questions

What information is needed for control-valve sizing?
For accurate trim selection, the minimum/normal/maximum flow rates, inlet/outlet pressures (or differential pressure), fluid type and temperature, specific gravity/viscosity, and upstream/downstream pipe diameters are required. Based on this information, the Cv value is calculated and cavitation/flashing potential is reviewed before determining the trim type and body size. Provide the operating conditions during the design phase and we will respond with a sizing sheet and appropriate specification.
How do I select the plug characteristic (Equal Percentage / Linear / Quick Open)?
Selection is based on the system's pressure-loss distribution. If the valve's own pressure drop accounts for 50% or more of the total system drop, choose Linear; if 25% or less, choose Equal Percentage; for simple open/close use closer to ON/OFF, Quick Open is suitable. PLV-21 supports all three characteristics, so select based on the system's pressure profile.
Which trim should be selected for lines where cavitation is a concern?
Single-stage trim drops pressure all at once, which can cause local pressure to fall below saturation vapor pressure and induce cavitation. In PLV-21, wear-resistant trim with STELLITE or HF overlay can be combined to slow damage progression, along with a balanced cage structure to drop pressure in stages. Tell us the specific pressure and flow conditions and we will review cavitation and propose an appropriate trim.
What is the supported seat leakage class?
PLV-21 supports ANSI CLASS IV with metal seats and ANSI CLASS V with soft seats. CLASS IV is the standard for typical continuous-process lines, while CLASS V soft seats are selected for combined ON/OFF lines requiring precise leakage control. Tell us the required leakage class and operating temperature and we will advise on the appropriate seat specification.
Which parts are typically replaced during maintenance?
The most frequently inspected and replaced parts are the stem packing and the plug/seat-ring set. Packing is subject to regular inspection and replacement based on operating hours and cycle count, while the plug and seat are serviced when seat leakage exceeds the threshold. This product allows trim assembly maintenance by removing only the upper bonnet without disassembling the body, so line downtime can be kept relatively short during maintenance.