Alicat VC Series Volumetric Flow Controller - Manual (Page 5)

5
Thank you for purchasing an MC or VC Series Gas Flow Controller. Please take the time to find and
read the information contained in this manual. This will help to ensure that you get the best possible
service from your instrument. This manual covers the following Alicat Scientific instruments:
MC Series 16 Bit Mass Gas Flow Controllers MC-XXSCCM-D
MC-XXSLPM-D
MCR-XXXSLPM
VC Series 16 Bit Volumetric Gas Flow Controllers VC-XXCCM-D
VC-XXLPM-D
VCR-XXXLPM
Installation
Plumbing
All MC and VC Series Gas Flow Controllers are equipped with female inlet and outlet port connections.
Because the flow controllers set up a laminar flow condition within the flow body, no straight runs of pipe
are required upstream or downstream of the controller. The inlet and outlet ports are equal in size and
symmetric (in-line). The port sizes (process connections) and mechanical dimensions for different flow
ranges are shown on pages 36-39.
Controllers with M5 (10-32) ports have o-ring face seals and require no further sealant or tape. On
other controllers, avoid the use of pipe dopes or sealants on the ports as these compounds can cause
permanent damage to the controller should they get into the flow stream. Use of thread sealing Teflon
tape is recommended to prevent leakage around the threads. When applying the tape, avoid wrapping
the first thread or two to minimize the possibility of getting a piece of shredded tape into the flow stream.
When changing fittings, always clean any tape or debris from the port threads.
It is also recommended that a 20 micron filter be installed upstream of controllers with full scale ranges
of 1(S)LPM or less and a 50 micron filter be installed upstream of controllers with full scale ranges
above 1(S)LPM.
Mounting
All MC and VC Series Gas Flow Controllers have mounting holes for convenient mounting to flat panels.
The sizes and dimensions for the mounting holes are shown on pages 40-42. Position sensitivity is not
generally an issue with small valve controllers. Large valve controllers are somewhat position sensitive
because of the fairly massive stem assembly. It is generally recommended that they be mounted so
that the valve cylinder is vertical and upright. The primary concern in mounting a large valve controller
in a position other than the recommended position is the increased risk of leakage when the controller
is given a zero set-point and is being held closed by the spring force.
Application
Maximum operating line pressure is 145 PSIG (1 MPa).
Caution: Exceeding the maximum specified line pressure may cause permanent damage to the
solid-state differential pressure transducer.
If the line pressure is higher than 145 PSIG (1 MPa), a pressure regulator should be used upstream
from the flow controller to reduce the pressure to 145 PSIG (1 MPa) or less if possible. Many of our
controllers are built after extensive consultations with the customer regarding the specific application.
The result is that two controllers with the same flow range and part number may look and act quite
differently depending upon the application the controller was built for. Care should be taken in moving a
controller from one application to another to test for suitability in the new application. Note that volumetric
meters and controllers are not recommended for high pressure or high backpressure applications (see
page 33).