Type Y696
D101770X012
Instruction Manual
Form 5312
January 2002
www.FISHERregulators.com
Type Y696 Vapor Recovery Regulator
Introduction
Scope of Manual
This instruction manual includes installation, startup,
maintenance, and parts information for the Type Y696
vapor recovery regulator.
Product Description
The Type Y696 vapor recovery regulator is a direct-
operated regulator with internal registration requiring no
downstream control line. It is used to sense increase in
vessel pressure and vent excessive internal vessel
pressure to an appropriate vapor recovery disposal or
reclamations system.
Specifications
The Specifications section lists maximum pressures,
temperatures, and other specifications. Specifications
for a given regulator as it originally comes from the
factory are stamped on the spring case nameplate.
Principle of Operation
The Type Y696 is used to maintain a constant inlet
(blanket) pressure with the outlet flowing to a system
whose pressure is lower than that at the inlet.
When vessel pressure increases above the set point of
the regulator due to pumping in or thermal heating, the
force of the control spring is overcome by pressure
acting on the diaphragm. This moves the disk away
from the orifice allowing gas to flow from the vessel to
the vapor recovery system.
As vessel pressure is reduced, the force of the control
spring causes the disk to move toward the orifice decreas-
ing the flow of gas out of the vessel. As vessel pressure
drops below the set point of the regulator, the disk will seat
against the orifice shutting off the flow of gas.
Figure 1. Type 696 Vapor Recovery Regulator
W5996
Installation
Personal injury, equipment damage, or
leakage due to escaping accumulated
gas or bursting of pressure-containing
parts may result if the vapor recovery
regulator is overpressured or installed
where service conditions could exceed
the limits given in the Specifications
section, or where conditions exceed any
ratings of the adjacent piping or piping
connections. To avoid such injury or
damage, provide pressure-relieving or
pressure-limiting devices to prevent
service conditions from exceeding those
limits.
Additionally, physical damage to the
vapor recovery regulator could result in
personal injury and property damage
due to escaping accumulated gas. To
avoid such injury and damage, install
the vapor recovery regulator in a safe
and well ventilated location.
