RU218126U1 - Diffusion steam oil pump - Google Patents

Abstract

The utility model relates to vacuum technology, namely to the means of obtaining a high vacuum. The technical problem to be solved by the proposed utility model is to reduce the reverse flow of working fluid vapor and increase the maximum outlet pressure through the use of a working fluid film of optimal thickness.

для формирования пленки рабочей жидкости высотой

Diffusion steam-oil pump consists of a vertically mounted cylindrical body and inlet and outlet pipes fixed in it, a multi-stage steam pipeline with umbrella nozzles in the central part along the axis of the body, a water seal fixed on the outer side of the heater bottom, a cooling jacket and annular ducts formed between the labyrinth ring package stepwise coupled with each other with a decrease in the thickness of the bottom from the periphery to the center, creating a stepped design of the bottom, characterized in that the holes in the labyrinth rings are located at a height

to form a working fluid film with a height

The technical result is a reduction in the reverse flow of working fluid vapor and an increase in outlet pressure.

Description

The utility model relates to vacuum technology, namely to the means of obtaining a high vacuum. The technical problem to be solved by the proposed utility model is to reduce the reverse flow of working fluid vapor and increase the maximum outlet pressure through the use of a working fluid film of optimal thickness.

A diffusion pump is a vacuum pump designed to create a high vacuum. Diffusion pumps are widely used in many areas of science and technology as a reliable and relatively cheap means of obtaining high vacuum. This was largely facilitated by their main advantages: the ability to provide high speed of action in a fairly wide range of pressures, the ability to pump out various types of gases, the reliability of the design, the absence of moving parts and ease of operation.

A known design of a diffusion vacuum pump [Patent SU 556244 dated 1973.01.08, IPC F04F 9/00(2006.01)]. The diffusion pump contains a cooled housing with a steam line along the axis. The steam pipeline is equipped with nozzles, and a boiler is located in its lower part.

In this diffusion pump, explosive boiling of the working fluid occurs in a large volume. During the explosive boiling of a liquid, the density of the steam jet changes, which leads to an increase in the reverse flow of working fluid vapor into the pumped out volume, as a result, the pumped out volume is contaminated with vapors of the pump working fluid. In addition, this design leads to losses in the power supplied to the boiler due to the lack of thermal insulation of the uncooled area of the housing.

A known design of the diffusion pump [Patent SU 584102 dated 1974.05.16, IPC F04F 9/02(2006.01)], containing a housing with an upper cooled zone. The diffusion pump is equipped with inlet and outlet nozzles, and contains a multi-stage steam pipeline located along the casing axis.

In this diffusion pump, explosive boiling of the working fluid occurs in a large volume. During the explosive boiling of a liquid, the density of the steam jet changes, which leads to an increase in the reverse flow of working fluid vapor into the pumped out volume, as a result, the pumped out volume is contaminated with vapors of the pump working fluid.

A known design of a diffusion oil-vapor pump, which is a prototype of the proposed utility model, is described in [Patent SU 1373908 A1 dated 1986.09.10, IPC F04F 9/02(2006.01)]. Diffusion steam oil pump contains a housing with a bottom filled in the lower part with a working fluid and a package of labyrinth rings placed in it. A heater is fixed on the outer side of the bottom. A multi-stage steam pipeline with umbrella nozzles is installed along the body axis. Moreover, the bottom is provided with annular ducts located inside the package of rings, stepwise coupled with each other with a decrease in the thickness of the bottom from the periphery to the center, creating a stepped design of the bottom. The pump contains an inlet and outlet pipe, a water seal and a cooling jacket.

However, explosive boiling of the working fluid in a large volume occurs in the specified diffusion steam-oil pump. During the explosive boiling of a liquid, the density of the steam jet changes and leads to an increase in the reverse flow of working fluid vapor into the pumped out volume, which leads to contamination of the pumped out volume with vapors of the pump working fluid.

The objective (technical result) of the proposed utility model is to reduce the reverse flow of working fluid vapor and increase the maximum outlet pressure.

для формирования пленки рабочей жидкости высотой

На фиг. 1 представлен чертеж диффузионного паромасляного насоса, на фиг. 2 изображены графики зависимости коэффициента теплоотдачи от высоты пленки рабочей жидкости при разных тепловых потоках. На фиг. 3 представлены графики изменения давления во времени при разных толщинах пленки.The task is achieved by the fact that the diffusion steam-oil pump consists of a vertically mounted cylindrical housing, and fixed inlet and outlet pipes, a multi-stage steam pipeline with umbrella nozzles in the central part along the axis of the housing, a hydraulic seal fixed on the outer side of the heater bottom, a cooling jacket, and annular ducts formed between the package of labyrinth rings stepwise paired with each other with a decrease in the thickness of the bottom from the periphery to the center, creating a stepped design of the bottom, in addition, the package of labyrinth rings has holes at a height

to form a working fluid film with a height

In FIG. 1 shows a drawing of a diffusion oil-vapor pump, in Fig. 2 shows graphs of the dependence of the heat transfer coefficient on the height of the working fluid film at different heat fluxes. In FIG. 3 shows graphs of the change in pressure over time for different film thicknesses.

The drawing shows a diffusion steam-oil pump (Fig. 1), consisting of a cylindrical body (1), a bottom (2), an inlet pipe (11), an outlet pipe (12), a multi-stage steam pipeline (5) with umbrella nozzles (6), a heater (7), cooling jackets (8), water seal (9), annular channels (10) with a package of labyrinth rings (4), working fluid (3).

для формирования пленки рабочей жидкости высотой

Diffusion steam oil pump operates as follows (Fig. 1). Previously, the inlet pipe (11) is docked to the body of the corresponding process unit (not shown in the drawing), in which the vacuum specified by the process mode is created and maintained. Then, a backing pump (not shown in the drawing) is docked to the outlet pipe (12) and turned on, creating a vacuum in the outlet pipe (12) sufficient to operate the diffusion oil-vapor pump. Then the heater (7) is turned on to heat and evaporate the working fluid (3). The resulting vapors of the working fluid flow through the steam lines (5) to the umbrella nozzles (6), flow out of them with the formation of a working jet, which entrains the gases entering the inlet pipe. Then the vapors of the working fluid condense on the walls of the housing (1), cooled by water supplied to the cooling jacket (8). Further, the working fluid (3) flows along the wall of the housing (1), enters the annular space of the hydraulic seal (9), after which it flows through the outer ring of the package (4) and enters the outer annular duct (10), where a thin layer of working fluid is formed ( 3) and film evaporation begins. The working fluid (3) enters the next annular channels (10) only through the hole in the labyrinth ring, making its way through the labyrinth and evaporating along the way. Stepped bottom design (2) with a package of labyrinth rings (4), which have holes at a height

to form a working fluid film with a height

увеличивается коэффициент теплоотдачи при испарении/кипении рабочей жидкости, и снижаются пульсаций паровой струи в процессе работы диффузионного паромасляного насоса. На фиг. 2 показано, что использование пленки рабочей жидкости толщиной

(где,

- капиллярная постоянная), по сравнению с более толстыми и более тонкими пленками жидкости, приводит к увеличению коэффициента теплоотдачи в процессе испарения/кипения рабочей жидкости, при высоком критическом тепловом потоке как показано в работе [Влияние высоты слоя на теплообмен и критический тепловой поток при испарении жидкости в условиях низких давлений / В.И. Жуков, А.Н. Павленко, Ю.В. Нагайцева, Д. Вайсе // Теплофизика высоких температур. - 2015. - Т. 53, № 5. - С. 727-734]. Кроме того, на фиг. 3 показано, что использование пленки рабочей жидкости толщиной

имеет меньшие пульсации давления в процессе испарения/кипения.Due to the use of a working fluid film with a height

the heat transfer coefficient increases during evaporation/boiling of the working fluid, and the steam jet pulsations decrease during the operation of the diffusion steam-oil pump. In FIG. 2 shows that the use of a working fluid film with a thickness

(Where,

- capillary constant), compared with thicker and thinner liquid films, leads to an increase in the heat transfer coefficient in the process of evaporation / boiling of the working fluid, with a high critical heat flux as shown in [Influence of layer height on heat transfer and critical heat flux during evaporation liquids under low pressure conditions / V.I. Zhukov, A.N. Pavlenko, Yu.V. Nagaitseva, D. Weisse // Thermophysics of High Temperatures. - 2015. - T. 53, No. 5. - S. 727-734]. In addition, in FIG. 3 shows that the use of a working fluid film with a thickness

has less pressure fluctuations during evaporation/boiling.

приводит к образованию оптимальной высоты пленки рабочей жидкости

что позволяет уменьшить обратный поток паров рабочей жидкости и увеличить наибольшее выпускное давление.Thus, the diffusion pump, as a result of the use of labyrinth rings with holes at a height

leads to the formation of the optimal height of the working fluid film

which allows to reduce the reverse flow of working fluid vapor and increase the maximum outlet pressure.

Claims (1)

Diffusion steam-oil pump, consisting of a vertically mounted cylindrical body and inlet and outlet pipes fixed in it, a multi-stage steam pipeline with umbrella nozzles in the central part along the axis of the body, a water seal fixed on the outer side of the heater bottom, a cooling jacket and annular ducts formed between the labyrinth rings, stepwise paired with each other with a decrease in the thickness of the bottom from the periphery to the center, creating a stepped design of the bottom, characterized in that the holes in the labyrinth rings are located at a height

to form a working fluid film with a height

Where

is the capillary constant.

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