GB2100351A - Steam ejector pumping system - Google Patents

Abstract

A pumping system for lifting liquids comprises two or more known steam ejectors 1, 2, arranged coaxially as an integral unit with the divergent portion 5 of one ejector connecting directly with the convergent portion 3 of the next following ejector. <IMAGE>

Description

SPECIFICATION Improved pumping system The present invention concerns a pumping system for lifting liquids from a low level to a high level.

It is common to employ steam ejectors for pumping or lifting liquids. Such a steam ejector comprises a casing or body including a combining passage having a convergent portion, a throat portion and a divergent portion, means for admitting a liquid into the casing or body upstream of the convergent portion and nozzle means for admitting steam into the convergent portion, said nozzle means being directed along the axis of the ejector.

Conventional steam ejectors of the type defined above can only pump or lift a liquid through a certain predetermined maximum height. If it is required to lift the liquid through a greater height it becomes necessary to pump in stages, each stage having its own ejector with associated steam lines and the like ancillary equipment.

It is now observed that an improved lifting capability can be obtained by arranging at least two steam ejectors as an integral end-to-end construction which eliminates the duplication of ancillary equipment and simplifies the installation.

According to the present invention a liquid pumping system comprises at least two steam ejectors as hereinbefore defined arranged coaxially as an integral unit with the divergent portion of one ejector connecting directly with the convergent portion of the next following ejector.

The velocity of the liquid decreases along the divergent portion of each ejector. In the case of the first ejector of the integral unit it is necessary to ensure that the length of the divergent portion is not unduly long whereby the velocity of the liquid emerging into the accelerating convergent portion of the next following ejector is not too low.

The invention will be described further by way of example with reference to the accompanying drawings in which: Figure 1 is a schematic sectional view of two steam ejectors forming a pumping system; and Figure 2 is an alternative form of steam ejector.

Figure 1 shows two substantially identical steam ejectors 1 and 2 connected together in an end-to-end relationship. Each ejector comprises a casing having a convergent portion 3, a throat portion 4, and a divergent portion 5. Each ejector further includes inlet nozzle 6 which is arranged to direct steam from a supply line 7 into the convergent portion 3. The nozzles 7 are substantially coaxial and arranged along the axis of the ejectors. A flow of liquid to be pumped is indicated by the arrows 8.

In operation the ejectors can be immersed in the liquid to be pumped, or arranged above the level of the liquid to induce flow by suction lift if the density and vapour pressure of the liquid is suitable. The application of steam to issue from the nozzles causes the liquid to be lifted or pumped through a height which is considerably in excess of that obtainable with a singie ejector, and at least equal to the performance of an equal number of separate ejector units operating in series.

Figure 2 shows an alternative form of ejector in which liquid to be pumped is introduced through a side port 9. The steam nozzle 6 is located as before on the axis of the ejector. As in the case of Figure 1 two such ejectors can be joined together with the divergent portion of one connecting with the convergent portion of the next following ejector to provide a pumping system.

Although mention is made of two ejectors coupled together it is possible to employ more than two in a pumping system.

1. A pumping system for liquids comprising at least two steam ejectors each ejector having a casing forming a combining passage having an upstream convergent portion, an intermediate throat portion and a downstream divergent portion, and nozzle means directed along the axis of the casing for admitting steam into the convergent portion, in which the ejectors are connected in series with the downstream end of the casing of each ejector being connected directly to the upstream end of the casing of the next following ejector in the series.

2. A pumping system for liquids substantially as herein described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improved pumping system The present invention concerns a pumping system for lifting liquids from a low level to a high level. It is common to employ steam ejectors for pumping or lifting liquids. Such a steam ejector comprises a casing or body including a combining passage having a convergent portion, a throat portion and a divergent portion, means for admitting a liquid into the casing or body upstream of the convergent portion and nozzle means for admitting steam into the convergent portion, said nozzle means being directed along the axis of the ejector. Conventional steam ejectors of the type defined above can only pump or lift a liquid through a certain predetermined maximum height. If it is required to lift the liquid through a greater height it becomes necessary to pump in stages, each stage having its own ejector with associated steam lines and the like ancillary equipment. It is now observed that an improved lifting capability can be obtained by arranging at least two steam ejectors as an integral end-to-end construction which eliminates the duplication of ancillary equipment and simplifies the installation. According to the present invention a liquid pumping system comprises at least two steam ejectors as hereinbefore defined arranged coaxially as an integral unit with the divergent portion of one ejector connecting directly with the convergent portion of the next following ejector. The velocity of the liquid decreases along the divergent portion of each ejector. In the case of the first ejector of the integral unit it is necessary to ensure that the length of the divergent portion is not unduly long whereby the velocity of the liquid emerging into the accelerating convergent portion of the next following ejector is not too low. The invention will be described further by way of example with reference to the accompanying drawings in which: Figure 1 is a schematic sectional view of two steam ejectors forming a pumping system; and Figure 2 is an alternative form of steam ejector. Figure 1 shows two substantially identical steam ejectors 1 and 2 connected together in an end-to-end relationship. Each ejector comprises a casing having a convergent portion 3, a throat portion 4, and a divergent portion 5. Each ejector further includes inlet nozzle 6 which is arranged to direct steam from a supply line 7 into the convergent portion 3. The nozzles 7 are substantially coaxial and arranged along the axis of the ejectors. A flow of liquid to be pumped is indicated by the arrows 8. In operation the ejectors can be immersed in the liquid to be pumped, or arranged above the level of the liquid to induce flow by suction lift if the density and vapour pressure of the liquid is suitable. The application of steam to issue from the nozzles causes the liquid to be lifted or pumped through a height which is considerably in excess of that obtainable with a singie ejector, and at least equal to the performance of an equal number of separate ejector units operating in series. Figure 2 shows an alternative form of ejector in which liquid to be pumped is introduced through a side port 9. The steam nozzle 6 is located as before on the axis of the ejector. As in the case of Figure 1 two such ejectors can be joined together with the divergent portion of one connecting with the convergent portion of the next following ejector to provide a pumping system. Although mention is made of two ejectors coupled together it is possible to employ more than two in a pumping system. CLAIMS

1. A pumping system for liquids comprising at least two steam ejectors each ejector having a casing forming a combining passage having an upstream convergent portion, an intermediate throat portion and a downstream divergent portion, and nozzle means directed along the axis of the casing for admitting steam into the convergent portion, in which the ejectors are connected in series with the downstream end of the casing of each ejector being connected directly to the upstream end of the casing of the next following ejector in the series.

2. A pumping system for liquids substantially as herein described with reference to and as illustrated in the accompanying drawings.