sight glass

sight glass

[′sīt ‚glas]

(engineering)

A glass tube or a glass-faced section on a process line or vessel; used for visual reading of liquid levels or of manometer pressures.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

sight glass

A glass tube used to indicate the liquid level in a pipe, tank, or the like.

McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

sight glass

Liquid refrigerant flows past the sight glass. If the charge of refrigerant is low, bubbles will be seen. A fully charged system has no bubbles.

A gunsight.

i. A transparent tube on the outside of a reservoir or tank that shows the level of the fluid in the container.
ii. A small window in the high side of a vapor-cycle cooling system. The system is fully charged if there are no bubbles seen in the sight glass.
iii. The transparent glass of a gun sight or a head-up display.

An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved