Mechanical seal

Abstract

A mechanical seal for preventing the leakage of fluid through the rotary sliding contact surfaces, in which a contact surface is provided with a plurality of fine one-way grooves having outer closed end portions. The fine grooves which are inclined outwardly and rearwardly to the relative rotation can be formed in the sliding contact surface of either the rotating member or the stationary member. If the fine grooves are formed radially or inclined outwardly and forwardly, the fine grooves may be formed in the sliding contact surface of the rotating member. The mechanical seal having such fine grooves in the sliding contact surface gives a quite good sealing effect because, during the rotation of rotating members, the leakage flow of the pressurized fluid or a mixture of liquid and gas that is sealed in on the outside thereof toward the external gas existing on the inside thereof, can be avoided. In another embodiment of the above mechanical seal having the fine grooves, the peripheral portion of at least one sliding contact surface is somewhat raised in the direction of the axis of the rotary shaft so as to increase the contact pressure between the contact surfaces, thereby enhancing the sealing effect during the stoppage of the rotating members. Therefore, the sealing effect in all the use conditions can be much improved.