Groth 3011L - Manual (Page 3)

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INTRODUCTION:
The blanket gas regulator is one of the principal components typically installed on a storage tank to protect the tank and its
contents. It is a precision regulator that is capable of maintaining a very low gas pressure (1/2" WC minimum) in the tank by
controlling the flow of a high pressure (200 PSI maximum) blanketing gas. It maintains a positive tank pressure when fluid is
pumped out or as fluid temperature decreases.
Typically nitrogen or another compatible gas is used to suppress the tank product vapors. This reduces losses due to product
evaporation and prevents atmospheric contaminants, including moisture, from entering the tank, preventing tank corrosion and
product contamination. The use of an inert blanketing gas minimizes air pollution due to leakage or emergency venting.
In addition to the blanketing regulator, a tank must be protected from structural damage by pressure and vacuum relief valves. A
typical tank installation is shown in Figure 3, which includes the regulator, a pressure vacuum relief valve and an emergency
pressure relief valve. Groth Corporation manufacturers all of these devices.
The regulator must be maintained by a knowledgeable valve technician. It should only be assembled under clean conditions,
preferably in a shop environment. Carefully read and understand this manual before attempting to adjust set pressure or flow
capacity, or repair the regulator.
For information not contained in this manual, please contact:
Groth Corporation
13650 N. Promenade Blvd
Stafford, TX 77477
281-295-6800 (Phone)
281-295-6995 (Fax)
DESIGN, FUNCTION & OPERATION
The Groth Model 3011L, 3011H, 3011HP, 3041L, 3041H, & 3041HP Regulators are high capacity, spring operated, diaphragm
type, balanced piston regulators, designed for tank blanketing applications.
The regulator controls the flow of blanketing gas to the vapor space in the storage tank. When the internal pressure of the tank is
at or above set pressure, the diaphragm force exceeds the spring force and the regulator is shut off bubble tight. When the tank
pressure falls below the set point, the spring force opens the regulator and blanket gas flows into the tank (See Figures 1 and 2).
FIGURE 1: MODEL 3011L - SHUT-OFF CONDITION FIGURE 2: MODEL 3011H - FLOWING CONDITION