Fig. 53.
The main gland is screwed up by means of six bolts, and to prevent the gland from locking itself in the stuffing-box, it is necessary that the nuts should be turned together. This is done in a simple and ingenious manner. One-half of each nut is provided with teeth, and these gear with a toothed wheel which has a rim only; this rim is held up by a ring C. When one nut is turned, all the rest follow in the same direction.
Exercise 54: Gland and Stuffing-box for Piston Rod of Large Inverted Cylinder Engine.—The lower view in fig. 53 is a half plan looking upwards, and a half section of the gland looking downwards. The upper view is a vertical section. Complete all these views and add an elevation. Scale 3 inches to a foot.
Note.—The large nuts, the wheel, the supporting ring, and small gland are made of brass.
Dimensions of Stuffing-boxes and Glands.
| d | = diameter of rod. | t1 = thickness of stuffing-box flange. |
| d1 | = diameter of box (inside). | t2 = thickness of gland flange. |
| l | = length of stuffing-box bush. | t3 = thickness of bushes in box and gland. |
| l1 | = length of packing space. | d2 = diameter of gland bolts. |
| l2 | = length of gland. | n = number of bolts. |
| t | = thickness of metal in stuffing-box. |
| d | d1 | l | l1 | l2 | t | t1 | t2 | t3 | d2 | n |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1¾ | 3⁄4 | 2 | 1½ | 7⁄16 | 1⁄2 | t2=t | 3⁄16 | 7⁄16 | 2 |
| 1½ | 2½ | 1¼ | 25⁄8 | 2 | 9⁄16 | 11⁄16 | when gland | 1⁄4 | 5⁄8 | 2 |
| 2 | 3½ | 1¾ | 3¼ | 2½ | 11⁄16 | 7⁄8 | flange is | 5⁄16 | 3⁄4 | 2 |
| 2½ | 41⁄8 | 2¼ | 37⁄8 | 27⁄8 | 13⁄16 | 11⁄16 | made of | 5⁄16 | 7⁄8 | 2 |
| 3 | 4¾ | 2¾ | 4½ | 3¼ | 15⁄16 | 1¼ | cast iron | 3⁄8 | 1 | 2 |
| 3½ | 5¼ | 3 | 51⁄8 | 35⁄8 | 1 | 13⁄8 | and t2=t1 | 3⁄8 | 1 | 2 |
| 4 | 57⁄8 | 3¼ | 5¾ | 4 | 1 | 13⁄8 | when gland | 7⁄16 | 1 | 2 |
| 4½ | 63⁄8 | 3½ | 63⁄8 | 43⁄8 | 11⁄16 | 19⁄16 | flange is | 7⁄16 | 7⁄8 | 4 |
| 5 | 7 | 3¾ | 7 | 45⁄8 | 11⁄16 | 19⁄16 | made of | 7⁄16 | 1 | 4 |
| 6 | 8 | 4¼ | 8¼ | 5 | 11⁄8 | 111⁄16 | brass. | 1⁄2 | 1¼ | 4 |
The proportions of glands and stuffing-boxes vary considerably but the above table represents average practice.
Exercise 55:—Make the necessary working drawings for a gland and stuffing-box for a locomotive engine piston rod 2½ inches in diameter, to the dimensions given in the table.