JPS5977007A - Gas leakage detecting device for mechanical seal - Google Patents

Abstract

PURPOSE:To surely and simply detect gas-leakage from a mechanical seal, by providing a trap chamber in the mechanical seal on the side opposite to a chamber in which gas flows, so that leak gas is trapped in this trap chamber and is led to a gas detector after being separated from oil. CONSTITUTION:A mechanical seal 8 seals between a turbin casing body 1 and a turbine shaft 2 and between front and rear bearing boxes 18, 19. That is, the mechanical seal 8 prevents the inflow of gas at a slide surface 66 by pressing a stationary ring 42 and a loose ring 41 against the slide surface 66 with the use of hydraulic pressure supply from an oil pump 15. In this stage, if the loose ring 41 is damaged so that gas flows in through the slide surface 66, this gas enters through a gap 5 into a trap chamber 50 where oil is separated from the gas, and then is transferred to a gad detector 62 through a trapping lne 60. Accordingly, the gas detector 62 is operated to indicate gas leakage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a refrigerant turbine, and more particularly to a device for detecting gas leakage due to damage to a mechanical seal by providing a gas collection section in a bearing box.

[Prior art]

For shaft seals of turbines that utilize cold gas such as LNG, it is necessary to attach a mechanical seal to a round part that prevents gas fluid from leaking from the rotating shaft.

As the sealing end surface of the mechanical seal wears, it consists of a floating ring that can move in the axial direction and a stationary ring that does not move, and has a buffer mechanism to maintain the seal with the rotating ring. In order to satisfy this mechanical seal mechanism, the oil pump in the main oil tank is used to supply oil, and the gas pressure in the passenger compartment is increased. 7 Maintain lubrication and airtightness of the sealed end surface, and operate at 01'.
It is made into Noh.

If damage occurs to the sliding part of the mechanical seal or if an accident occurs in the seal oil supply line, the oil will flow into the single chamber side and be led to the oil separation tank and seal oil recovery tank. Damage to these mechanical seals is confirmed by an oil level gauge installed in the tank, a level switch alarm, etc., and the turbine is stopped. Naturally, due to damage to the mechanical seal, the gas in the single chamber flows into the bearing box and is exhausted to the atmosphere via the vent line, but there are the following problems.

(1) The degree of damage to the mechanical seal can be determined by checking the amount of oil leaking into the tank using an oil level gauge, etc.
Difficult to detect in trace amounts.

(2) Although the oil leakage to the tank side is a small amount of the specified value,
If gas had flowed into the bearing box, damage to the mechanical coolant could not be detected by managing only the amount of oil leakage.

(3) Since the diturbine is operated using low-temperature (NG gas) gas, if the oil leakage line freezes, there is a possibility that the mechanical seal will obstruct the flow of oil leakage, delaying confirmation of damage.

(4) Damage to mechanical seals is confirmed by oil leakage, making early detection difficult.

(5) In consideration of gas leaks from turbines, tanks, piping, etc., gas detectors are installed and maintained on the ceilings of buildings and near equipment, so we hope they will be effective immediately.

As mentioned above, there is a concern that damage to the mechanical seal may cause a turbine accident or an explosion due to gas leakage, and early detection is required.

[Purpose of the invention]

An object of the present invention is to provide a detection device that detects gas by providing a gas collection section at the tip of a mechanical seal in a cold-heat turbine and within a bearing box, and detects damage to the mechanical seal at an early stage to prevent accidents. It is in.

[Embodiments of the invention]

The present invention does not only detect damage to the mechanical coolant by checking the amount of oil leakage, but also enables early detection by reliably catching gas in the passenger compartment when it flows into the bearing box. do.

FIG. 1 shows a system system, in which a turbine casing body 1, a turbine shaft 2, and a front bearing box 18 are closely sealed by a mechanical seal 8. A stationary ring 42. The floating ring 41 is pressed against the seal ring 38 and the sliding surface 66 prevents gas from flowing into the compartment 49 side. Also, in order to lubricate the sliding surface, oil is supplied through the seal oil supply hole 53. If the mechanical seal floating ring 41 is damaged, regas flows through the sliding surface 66, and this gas flows through the gap 52 into the auxiliary tank chamber 50 together with oil supply. Oil is in the bearing box, gas (NG)
This is detected by a collection line 60 and a gas detector 62 installed in the upper part of the collection room, and an alarm is issued to stop the turbine as a result of damage to the mechanical seal and prevent an accident as soon as possible.

FIG. 3 shows another embodiment of the present invention. What is different from FIGS. 1 and 2 is that suction pipes 34 and 35 are taken out to the vent line piping of the bearing box 18 and 19, and a gas detector is installed. 36.3
7 so that it can be detected. vent line 20
．． 21 is exhausted to the roof of the building, so the vent line has a chimney effect, and the gas in the single chamber due to mechanical seal damage flows into the bearing box, is sucked into the bearing box vent and vent line, and is discharged, so piping Gas detection is still effective even with more branches.

Gas can be detected directly from the vent line without installing a collection chamber inside the bearing box. In the figure, 9 is the rear mechanical seal, 10 is the bearing oil supply line, 11 is the seal oil supply line, and 1
2 is an oil leakage system, 13 is a drain line, 14 is an oil supply line, 16 is a main oil tank, 17 is an oil pump suction part, and 64 is a collection plate.

〔Effect of the invention〕

According to the present invention, there are the following effects.

1) It is possible to confirm the amount of oil leaking into the tank by using f4 confirmation and gas detection in the collection chamber provided in the bearing box, making it easy and reliable to confirm damage to the mechanical seal.

2) By providing a collection chamber directly at the tip of the mechanical coolant, gas leaks can be caught quickly and damage to the mechanical seal can be detected early.

3) Even if a blockage occurs due to freezing of an oil leak line caused by low temperature gas (NG) in a cold turbine, it can be detected by gas detection.

[Brief explanation of the drawing]

Fig. 1 is a diagram of a mechanical seal oil leak system equipped with a gas collection section according to the present invention, Fig. 2 is a detailed diagram of the gas collection section according to the present invention, and Fig. 3 is a modified application system of a mechanical seal gas detector according to the present invention. It is a diagram. 62...63...Gas detector.

Claims (1)

[Claims] 1. In a low boiling point fluid turbine in which the shaft seal is equipped with a mechanical seal of the hydraulic seal type in order to prevent gas leakage, in order to detect that the shaft seal effect has been impaired, a chamber is installed to stop the flow of the gas of the mechanical seal. A mechanical seal gas leak comprising: a collection chamber with an upper semicircular shape and an open lower half provided on the opposite side of the gas leakage chamber; and means for facilitating collection of the gas and detecting leakage of the gas. Detection device.