SU943451A1 - Two-step end face seal - Google Patents

Description

(54) TWO-PERFORMANCE MECHANICAL SEAL

one

This invention relates to a sealing technique.

Two-stage mechanical seals are known, both stages of which are placed on the shaft sleeve, which forms a gate cavity with the seal casing, in which the impeller is located that provides circulation, liquids 1.

Their disadvantage is low performance due to the presence of stagnant zones.

The purpose of the invention is to increase the resource, Q ca seals.

To this end, in the area of the main seal, an additional contour of forced circulation of the filling and cooling fluid is made, including cavities formed by the outer surface 15 of the shaft and the groove on the inner surface of the sleeve, and two rows of radial channels of different lengths made at the ends of the said cavity a series of channels are located in the zone of the main seal 2o, and the other in the zone of the auxiliary seal.

FIG. 1 shows a two-stage mechanical seal, a general sectional view; on

FIG. 2 shows a possible embodiment of a rotating ring 2 with paddles.

Claims (3)

The two-stage mechanical seal consists of two end seals installed in series on the carrier sleeve 1. The main seal consisting of a rotating ring 2 and a stationary ring 3 is housed in the housing 4. The auxiliary seal consisting of a rotating ring 5 and the fixed ring 6 is housed in the housing 7. In the bolt cavity 8 connected by channels 9 and 10 with the external tank 11, located impeller 12. In the housing 4 is a labyrinth seal 13. The main seal is in contact with the compacted product and operates under pressure equal to the pressure in the stuffing box of the pump. The auxiliary seal operates under the pressure of the barrier and coolant circulating in a closed volume through channels 9 and 10 through the cavity 8 and the remote tank 11, in which the cooling coil 14 is placed, resulting in the removal of frictional heat from the main pair of friction consisting from rings 2 and 3, and an auxiliary pair of friction, made from rings 5 and 6. The auxiliary seal is designed for the same specific pressure as the main one in order to prevent the release of compacted product in the atmosphere in the event of a break o main seal. Through the channel 15 in the housing 4, connected to the pump pressure spiral, the cavity 16 formed by the main seal, the housing 4 and the labyrinth seal 13 circulates in small quantities the pumped liquid under a higher pressure than the pressure of the product to be partially removed. frictional heat from a pair of friction of the main seal. The valve 17 serves to release the evaporated compacted liquid to the receiver. The level of circulating valve and coolant is monitored through the sight glass 18. The two-stage mechanical seal operates as follows. When the shaft 19 rotates, the impeller 12 creates a pressure differential, due to which the main part of the valve And cooling fluid circulates along circuit A formed by the cavity 8, the remote tank 11 and channels 9 and 10. The other part of the valve and coolant is taken from the main flow of circuit A , under the action of a centrifugal force arising during the rotation of the shaft, passes through the additional contour B in the direction from the main friction pair to the secondary seal and returns to circuit A. Contour B consists of shaft 19 and other point on the inner surface of the cavity 20 of the sleeve 1 and two rows of channels 21 and 22 at the ends of the bore. The presence of an additional circuit of forced circulation of the sealing and coolant in the friction zone of the main seal eliminates evaporating leakage, flush out the wear products, effectively cooling the friction pair of the main seal, which reduces power consumption and increases the reliability and durability of the mechanical seal. Claim 1. A two-stage mechanical seal, mainly for liquefied gases, both stages of which are placed on the shaft sleeve, which forms with the seal housing a bolt cavity communicated with a gate and cooling fluid source, while the seal has means for circulating a fluid in the bolt cavity, different By the fact that, in order to increase the compaction resource, in the zone of the main seal, an additional contour of forced circulation of the valve and coolant is made. 2. Sealing according to claim 1, characterized in that the additional circuit is made in the form of a cavity between the shaft and the groove on the inner surface of the shaft sleeve, which communicates with the gate cavity by two rows of radial channels, one of which is made in the auxiliary sealing zone and the other in the zone of the main seal. 3. Seal on PP. 1 and 2, characterized in that the length of the radial channels located in the area of the auxiliary seal; made longer than the length of the channels of another row. Sources of information taken into account in the examination 1. US Patent No. 2824759, cl. 277-15, 1958.