Boekel Scientific 25515016 Cement Autoclave - Manual (Page 3)

1. Introduction
The Boekel cement autoclave is a device for conducting accelerated soundness tests on
cement according to ASTM C151. The autoclave is also suitable for other applications
requiring a constant steam pressure with corresponding constant temperature within the
60-PSIG to 350-PSIG range.
2. Description
2.1 General
The autoclave consists of a welded steel cylinder with bolted cover, mounted on a sturdy
supporting frame and enclosed in a heat insulated metal housing. (See Figure 1)
The steel cylinder is fitted with a high temperature gasket and a heavy cover held in place
by 16 cap screws bearing upon washers. A T-Handle wrench supplied with the autoclave
may be used to tighten the nuts gradually and uniformly to make a leak-proof assembly.
The cylinder assembly is designed for a safe working pressure of 525 PSIG, or one and
one-half the maximum working pressure. A safety valve set to release at 350 PSIG is
provided for protection and modification is not recommended for safe operation. A dial
pressure gage indicates the steam pressure in PSIG. Temperature readings are taken
with a No. NP22507 thermometer ASTM #2F, which is placed in the thermometer well
provided in the cylinder cover. An air-vent valve allows the escape of entrapped air
during the early part of the heating period and releases any steam pressure remaining at
the end of the cooling period.
The autoclave is heated by two electric heaters attached to the cylinder. The heating unit
is controlled from a switch panel on the control box. The control box houses the pressure
regulator.
A main toggle switch controls the entire electrical circuit including the automatic regulator.
Separate on-off toggle switches, in series with pilot lights, control the current to the two
heating elements. Switch functions are indicated on the switch panel.
2.2 Regulator
The pressure regulator controls pressures between 60 and 350 PSIG. It is located inside
the control cabinet and is provided with two screws. One screw is for adjustment of the
“range” and the other screw is for adjustment of the “differential”. (See Figure 2)
2.2.1 Range
The “Range” adjustment screw, when turned clockwise, raises the “make” and “break”
points of the circuit. The differential between “make” and “break” points, however, is not
altered by the screw adjustment. This screw has been factory set to maintain cylinder
pressure of 295 ± 10 PSIG.
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