GB2137743A

GB2137743A - Apparatus for venting and deaerating a liquid circuit

Info

Publication number: GB2137743A
Application number: GB08401936A
Authority: GB
Inventors: Hans Jurgen Guttmann
Original assignee: MAN Maschinenfabrik Augsburg Nuernberg AG
Current assignee: MAN AG
Priority date: 1983-01-25
Filing date: 1984-01-25
Publication date: 1984-10-10
Also published as: SE447206B; IT8420587V0; FR2539812A1; FR2539812B1; GB2137743B; DE8301939U1; GB8401936D0; SE8400119D0; NL8400219A; SE8400119L

Abstract

A surge tank (1) has a substantially horizontal expansion pipe (3) extending into the tank through a side wall. The expansion pipe (3) has an inlet (4) for liquid from a circuit, e.g. the coolant circuit of an i.c. engine, and the inlet has a cross-sectional area less than that of the pipe (3). In order to improve deaeration the expansion pipe (3) is arranged in the liquid (1b) and has a closed end (3a) outside the tank and an open end (3b) in the tank, the inlet (4) being located outside the tank (1) and being connected to a circumferential surface (3d) of the expansion pipe (3). <IMAGE>

Description

SPECIFICATION Apparatus for venting and deaerating a liquid circuit This invention relates to apparatus for venting and deaerating a liquid circuit, particularly but not exclusively, the coolant circuit of an internal combustion engine.

German Patent publication No. 30 02 578 discloses such apparatus comprising at least one pump and one surge tank provided for the conversion of velocity and expansion of the liquid entering from the liquid circuit. A horizontallyarranged expansion pipe extends through a wall of the surge tank and liquid from the circuit is admitted into the expansion pipe through a substantially smaller diameter inlet pipe.

A disadvantage of the known apparatus is its complexity and also that the throughput of coolant is low.

An object of the present invention to provide apparatus of the type initially referred to which features straightforward construction and permits a higher coolant throughput while ensuring reliable and extremely fine deaeration of the liquid contained in the circuit.

The invention provides apparatus for venting and dearating a liquid circuit, comprising a surge tank having a substantially horizontal expansion pipe extending into the surge tank through a side wall thereof, the expansion pipe having an inlet for admitting liquid from the circuit, the inlet having a cross-sectional area less than that of the expansion pipe, wherein the expansion pipe is arranged below an operational level of liquid in the tank and has a closed end outside the surge tank and an open end inside the surge tank, the inlet being located outside the surge tank and extending from a circumferential surface of the expansion pipe.

Such apparatus is easier to manufacture compared with the prior art because of special inlet pipe with deflection holes as well as a special discharge opening in the expansion pipe can be omitted.

An embodiment of the invention will now be described with reference to the accompanying drawing, in which: Fig. 1 is a schematic longitudinal elevation of apparatus according to the invention, and Fig. 2 is a section taken along the line Il-Il of Fig. 1.

In the drawing, the inside of a surge tank 1 has an air-containing portion 1 a serving as an expansion space and a liquid-containing portion 1b, the liquid level 5 fluctuating. Furthermore, the surge tank 1 is provided with a filler neck and a pressure control valve 6, and is formed with a discharge pipe 2.

An expansion pipe 3, arranged substantially horizontally in the liquid-containing portion 1 b of the surge tank extends from the outside through one wall of the tank. Fend 3a of the expansion pipe 3 located outside the surge tank is closed and end 3b inside the surge tank is open. An inlet pipe 4 is fitted to the circumference of that portion 3d of the expansion pipe 3 situated outside the surge tank. The inlet pipe 4 has a substantially smaller diameter through which the liquid is admitted to the expansion pipe 3 from a cooling circuit (not shown).

The water from the engine cooling circuit, which is to be vented, enters the expansion pipe 3 at a relatively high velocity, impinges on the opposite wall and is expanded due to the abrupt increase in cross sectional area. Subsequently, the water being vented flows at a relatively low velocity to the opening 3b of the expansion pipe 3.

Due to the lower flow velocity in the expansion pipe 3, air and gas bubbles in the coolant rise upwards, form larger bubbles and rise at the outlet 3b of the expansion pipe 3 into the air space 1 a of the surge tank 1.

The portion 3c of the expansion pipe situated inside the surge tank 1 is relatively long, firstly in order to obtain as long a bubbling distance as possible and, secondly to arranged the outlet end 3b of the expansion pipe 3 at a considerable distance from the discharge pipe 2 so that, as the coolant flows on (substantially in a direction opposite to that direction of flow in the expansion pipe owing to partitions provided in the surge tank which are not shown in the drawings) further gas bubbles can be separated during on this "free trajectory". Frbm the discharge pipe 2, the coolant returns to the engine.

Summarizing, it can be stated that the arrangement of the expansion pipe within the liquid in the surge tank results in a simpler configuration of venting apparatus compared with the apparatus disclosed in the German patent publication 30 02 578 where the expansion pipe is arranged above the liquid in the surge tank.

There are fewer components and the apparatus is less sensitive to changes in the position of the surge tank, provided the expansion pipe is completely under water. A specially straightforward configuration is obtained if the expansion pipe is formed integrally with the surge tank.

1. The invention provides apparatus for venting and deaerating a liquid circuit, comprising a surge tank having a substantially horizontal expansion pipe extending into the surge tank through a side wall thereof, the expansion pipe having an inlet for admitting liquid from the circuit, the inlet having a cross-sectional area less than that of the expansion pipe, wherein the expansion pipe is arranged below an operational level of liquid in the tank and has a closed end outside the surge tank and an open end inside the surge tank, the inlet being located outside the surge tank and extending from a circumferential surface of the expansion pipe.

2. Apparatus as claimed in Claim 1 , wherein the part of the expansion pipe inside the surge tank extends substantially over the full length of the surge tank.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Apparatus for venting and deaerating a liquid circuit This invention relates to apparatus for venting and deaerating a liquid circuit, particularly but not exclusively, the coolant circuit of an internal combustion engine. German Patent publication No. 30 02 578 discloses such apparatus comprising at least one pump and one surge tank provided for the conversion of velocity and expansion of the liquid entering from the liquid circuit. A horizontallyarranged expansion pipe extends through a wall of the surge tank and liquid from the circuit is admitted into the expansion pipe through a substantially smaller diameter inlet pipe. A disadvantage of the known apparatus is its complexity and also that the throughput of coolant is low. An object of the present invention to provide apparatus of the type initially referred to which features straightforward construction and permits a higher coolant throughput while ensuring reliable and extremely fine deaeration of the liquid contained in the circuit. The invention provides apparatus for venting and dearating a liquid circuit, comprising a surge tank having a substantially horizontal expansion pipe extending into the surge tank through a side wall thereof, the expansion pipe having an inlet for admitting liquid from the circuit, the inlet having a cross-sectional area less than that of the expansion pipe, wherein the expansion pipe is arranged below an operational level of liquid in the tank and has a closed end outside the surge tank and an open end inside the surge tank, the inlet being located outside the surge tank and extending from a circumferential surface of the expansion pipe. Such apparatus is easier to manufacture compared with the prior art because of special inlet pipe with deflection holes as well as a special discharge opening in the expansion pipe can be omitted. An embodiment of the invention will now be described with reference to the accompanying drawing, in which: Fig. 1 is a schematic longitudinal elevation of apparatus according to the invention, and Fig. 2 is a section taken along the line Il-Il of Fig. 1. In the drawing, the inside of a surge tank 1 has an air-containing portion 1 a serving as an expansion space and a liquid-containing portion 1b, the liquid level 5 fluctuating. Furthermore, the surge tank 1 is provided with a filler neck and a pressure control valve 6, and is formed with a discharge pipe 2. An expansion pipe 3, arranged substantially horizontally in the liquid-containing portion 1 b of the surge tank extends from the outside through one wall of the tank. Fend 3a of the expansion pipe 3 located outside the surge tank is closed and end 3b inside the surge tank is open. An inlet pipe 4 is fitted to the circumference of that portion 3d of the expansion pipe 3 situated outside the surge tank. The inlet pipe 4 has a substantially smaller diameter through which the liquid is admitted to the expansion pipe 3 from a cooling circuit (not shown). The water from the engine cooling circuit, which is to be vented, enters the expansion pipe 3 at a relatively high velocity, impinges on the opposite wall and is expanded due to the abrupt increase in cross sectional area. Subsequently, the water being vented flows at a relatively low velocity to the opening 3b of the expansion pipe 3. Due to the lower flow velocity in the expansion pipe 3, air and gas bubbles in the coolant rise upwards, form larger bubbles and rise at the outlet 3b of the expansion pipe 3 into the air space 1 a of the surge tank 1. The portion 3c of the expansion pipe situated inside the surge tank 1 is relatively long, firstly in order to obtain as long a bubbling distance as possible and, secondly to arranged the outlet end 3b of the expansion pipe 3 at a considerable distance from the discharge pipe 2 so that, as the coolant flows on (substantially in a direction opposite to that direction of flow in the expansion pipe owing to partitions provided in the surge tank which are not shown in the drawings) further gas bubbles can be separated during on this "free trajectory". Frbm the discharge pipe 2, the coolant returns to the engine. Summarizing, it can be stated that the arrangement of the expansion pipe within the liquid in the surge tank results in a simpler configuration of venting apparatus compared with the apparatus disclosed in the German patent publication 30 02 578 where the expansion pipe is arranged above the liquid in the surge tank. There are fewer components and the apparatus is less sensitive to changes in the position of the surge tank, provided the expansion pipe is completely under water. A specially straightforward configuration is obtained if the expansion pipe is formed integrally with the surge tank. CLAIMS

3. Apparatus as claimed in Claim 1 or 2, wherein the expansion pipe is formed integrally with the surge tank.

4. Apparatus as claimed in Claim 1 or 2, wherein the surge tank has a discharge pipe substantially adjacent the area where the expansion pipe extends into the surge tank.

5. Apparatus for venting and deaerating a liquid circuit substantially as herein described with reference to the accompanying drawing.

6. An internal combustion engine having a liquid cooling circuit and apparatus as claimed in any one of the preceding claims for venting and deaerating the liquid circuit.