FIELD OF THE INVENTION

The invention relates to devices for removing liquid condensate from gas-conveying heat transfer systems in a manner that restricts gas escape. Such devices are often used for removing condensate from steam-conveying pipelines, where they are known as steam traps.

BACKGROUND TO THE INVENTION

Steam is commonly used in industry as a medium for transporting heat energy from a central location via suitable pipelines to its point of use. The heat energy conveyed in the steam may be released at a suitable point by causing a phase change of the steam from gas to liquid. The phase change releases latent heat from the steam and causes liquid

condensate to form.

The condensate and any trapped air needs to be removed from the pipelines, because its presence can cause corrosion and reduce the system's heat transfer efficiency. However, any device for removing condensate also needs to prevent steam from escaping, as this also reduces the system' s heat transfer efficiency and may waste the energy transported by that steam.

GB 2 304 300 describes an example of a continuous flow fixed orifice (CFFO) steam trap. In such devices, an orifice is located in the flow path of steam travelling through a pipeline. The size of the orifice is chosen carefully such that the condensate, which flows through it much more slowly than the steam, acts to block the steam from passing.

US 4,745,943 discloses an orifice steam trap in which the orifice is formed as part of a venturi, i.e. a conduit having a constricted passage therein, the constricted passage having a smaller cross-sectional area then the remainder of the conduit. Condensate passing through the orifice thus enters a channel that opens out (e.g. flares outwardly) in the

direction of flow. A pressure drop after the orifice causes flash steam to form from the saturated condensate, thereby regulating condensate flow. SUMMARY OF THE INVENTION

At its most general, the present invention provides an orifice-type condensate removal device where the orifice is contained within an independently removable gas trap insert. The gas trap insert can be removably connectable at an inlet end to a upstream body of the condensate removal device, which includes its other components, e.g. flow inlet connection, debris filter, etc. The gas trap insert may be removably connected at an outlet end directly to the pipeline, i.e. such that an end face of the gas trap insert forms a seal with the pipeline when the condensate removal device is mounted in the pipeline .

This configuration of the condensate removal device may facilitate installation and removal of the gas trap insert for replacement and/or maintenance (e.g. cleaning of the orifice) . Additionally, use of the removable gas trap insert may reduce the number of welds that are required to assemble the

condensate removal device, which may reduce manufacturing costs and manufacturing time. Indeed, welding costs may represent a significant fraction of the manufacturing cost for a conventional condensate removal device As the gas trap insert is directly connectable to the pipeline, this may enable the number of components that are required to mount the condensate removal device in the pipeline to be reduced, such that the condensate removal device may have a simpler overall structure .

According to a first aspect of the invention, there is provided condensate removal device for mounting in a pipeline, the condensate removal device comprising: an upstream body configured to be connectable to an upstream portion of pipeline to receive a flow of condensable gas; and a gas trap insert comprising a condensate drainage channel extending between an inlet side and an outlet side of the gas trap insert, wherein the condensate drainage channel includes a constricted passage that is occludable by condensate flow to restrict condensable gas flow through the condensate drainage channel, wherein the inlet side is removably connectable to the upstream body, wherein the outlet side is configured to be directly connectable to a downstream portion of pipeline, and wherein the outlet side comprises an insert flange having a downstream-facing surface configured to sealingly abut the downstream portion of pipeline.

A flow path for the condensable gas and condensate is defined by the condensate removal device between the upstream body and the outlet side of the gas trap insert. The flow path may comprise a passageway extending from the upstream body to the outlet side of the gas trap insert, the passageway having one or more sections or sub-chambers. The passageway may be linear, in which case the sub-chambers may lie coaxially with the axis of the pipeline in which the device is mounted.

However, the passageway may also be convoluted, e.g. may comprise two or more bends, which may allow the sub-chambers to be located in regions offset from (e.g. at an angle to) the pipeline axis. This may have the advantage of permitting easier access to the sub-chambers, e.g. for cleaning or clearing debris from inside the device. The condensate removal device may be usable in a pipeline that conveys steam as the condensable gas (water being the condensate) , similar to the pipelines discussed above. However, the condensate removal device may also be used with different types of condensable gas and condensate which are transported through a pipeline.

The upstream body may comprise an interface for

connecting it to the upstream portion of pipeline. The upstream body may include, e.g. define, an inlet chamber. For example, the upstream body may have a flange with a sealing surface thereon, for forming a seal with the upstream portion of pipeline when the condensate removal device is mounted in the pipeline. The seal may be formed by a gasket or other suitable component between the flange on the upstream body and a corresponding flange on the pipeline. The upstream body may be connectable to the pipeline using conventional means, e.g. by using a clamp mechanism, or by bolting the upstream body flange to the corresponding flange on the pipeline.

The gas trap insert may be a unitary component which is connected between the upstream body and the pipeline. The inlet side of the gas trap insert is removably connected to the upstream body of the condensate removal device, meaning that the gas trap insert is detachable without causing physical damage to the device. In other words, the connection between the gas trap insert and the upstream body is

reversible such that it can be repeatedly made and unmade without cutting or otherwise damaging the device. Various suitable mechanisms may be used for removably connecting the gas trap insert to the upstream body. For example, the inlet side of the gas trap insert and the upstream body may have mateable connection portions. A seal may be formed at the connection between the gas trap insert and the upstream body, such that gas or condensate may not escape from the condensate removal device at the connection. For example, the seal may be designed to withstand pressures up to a pressure rating of the pipeline .

The gas trap insert may be substantially cylindrical for ease of manufacture, however other shapes are also possible (e.g. parallelepiped). The condensate drainage channel extending through the body of the gas trap insert forms part of the flow path discussed above. The constricted passage, which may be the narrowest portion of the condensate drainage channel, may correspond to and perform the functions of an orifice in an orifice trap as discussed above. The constricted passage may be arranged to substantially prevent condensable gas flow therethrough in operation. Thus, the cross-sectional area of the constricted passage, which may be circular, may be selected to permit condensate flowing therethrough to occlude the condensate drainage channel to prevent gas from flowing therethrough. The constricted passage may have a constant cross-sectional area. The constricted passage may be formed in an impermeable barrier that separates (e.g. isolates) the inlet side from the outlet side, e.g. by drilling, punching, lasering or the like. In some embodiments, the condensate drainage channel may increase in cross-sectional area as it extends away from the constricted passage towards to outlet side of the gas trap insert. The condensate drainage channel may thus resemble a venturi. The increase in cross-sectional area of the condensate drainage channel away from (i.e.

downstream from) the constricted passage may occur gradually, e.g. as an outward tapering of the channel, or stepwise.

Because the condensate drainage channel extends all the way to the outlet side of the gas trap insert, the condensate drainage channel in the condensate removal device of the invention may be longer than in conventional devices of the same length. This is because in conventional devices, the condensate drainage channel does not extend all the way to an outlet side of the device (e.g. an intermediate connecting component is usually provided between the condensate drainage channel and the pipeline) . Thus, the condensate drainage channel may taper outwardly between the constricted passage and the downstream-facing surface of the insert flange.

The insert flange may be an integrally formed part of the gas trap insert, e.g. by casting, forging or machining as a single part. Alternatively, the flange may be attached separately, e.g. by welding it to the body. It may be

advantageous for the insert flange to be integrally formed with the body, as this way the step of welding the flange to the body can be dispensed with.

The insert flange serves to connect the outlet side of the gas trap insert to the downstream portion of pipeline and form a seal with the pipeline. The outlet side of the gas trap insert thus acts as the outlet of the condensate removal device when the condensate removal device is mounted in the pipeline, as condensate exiting from the gas trap insert is delivered directly into the pipeline, without the need for any intermediate components. The downstream-facing surface of the insert flange may provide a sealing surface that forms a seal with the pipeline when the condensate removal device is mounted in the pipeline, such that gas or condensate may not escape at the connection between the device and the pipeline. For example, the downstream-facing surface of the insert flange may include a material thereon (e.g. PTFE, or a soft metal such as copper or brass) that forms a seal when secured against a sealing surface on the pipeline. In another example, the downstream-facing surface of the insert flange may be made of a hard material (e.g. of the same material as the body of the gas trap insert) , and the seal is formed by a gasket or other suitable component that is compressed between the front surface of the flange and a sealing surface on the pipeline when the condensate removal device is mounted in the pipeline. The downstream-facing surface of the insert flange may include a groove for receiving a gasket to form a seal with the downstream portion of pipeline.

The outlet side of the gas trap insert may be connectable to the pipeline by any suitable means. For example, the outlet side of the gas trap may be connected to the pipeline by clamping the insert flange to the pipeline, e.g. to a corresponding flange on the pipeline. In another example, the insert flange may include one or more through-holes, so that it can be bolted to the pipeline, e.g. to a corresponding flange on the pipeline. Alternatively, attachment means for securing the gas trap insert to the pipeline may be provided on the body of the gas trap insert, e.g. the body may include one or more connection points to which the pipeline can be bolted or otherwise secured.

An advantage of the condensate removal device of the invention is that the gas trap insert may be easily accessible and removable, even when the condensate removal device is mounted in the pipeline. Indeed, as the inlet side of the gas trap insert is removably connected to the upstream body, the gas trap insert may be removed simply by disconnecting the inlet side from the upstream body and the outlet side from the pipeline. Thus, removal of the gas trap insert may be

performed whilst leaving the upstream body of the condensate removal device in place on the pipeline. This may facilitate removal of the gas trap insert from the condensate removal device, in order to replace the gas trap insert or perform maintenance (e.g. cleaning the condensate drainage channel).

The use of a removable connection between the gas trap insert and the upstream body may also avoid the need for a welded connection, which may reduce manufacture costs, as welding may be a time consuming process. In contrast, in conventional condensate removal devices, the part of the device containing the condensate drainage channel is typically permanently attached (e.g. welded) to other components such as the flow input, such that access to the condensate drainage channel is not straightforward. Often, with conventional condensate removal devices it is necessary to undo and then redo welded connections when carrying out maintenance on the condensate drainage passage.

By using the outlet side of the gas trap insert as the outlet for the condensate removal device, there is no need for additional parts between the gas trap insert and the pipeline. In contrast, conventional condensate removal devices typically use an additional outlet part having an outlet chamber that is connected to the part containing the condensate drainage channel. This often requires further welded connections (e.g. between the parts or to connection flanges) . Thus, the condensate removal device may require fewer components so that manufacturing costs can be reduced.

A further advantage of the condensate removal device of the invention is that the gas trap insert is visible when the condensate removal device is mounted in a pipeline. This enables a user to visually inspect the gas trap insert when in use. For example, a serial number may be provided on the body of the gas trap insert, so that the user can identify the gas trap insert currently in use. This may enable the user to check that a gas trap insert having the correct drainage channel size is being used and/or when the next maintenance of the gas trap insert should be carried out.

The condensate removal device may further comprise an annular outlet flange disposed around an outer surface of the gas trap insert, wherein the annular outlet flange is

configured to engage an upstream portion of the insert flange, and wherein the annular outlet flange is configured to be connectable to the downstream portion of pipeline to thereby apply a downstream-directed force on gas trap insert. The gas trap insert may be mounted within a bore formed through the annular outlet flange. The bore may be larger than a cross- section of the body of the gas trap insert, such that the outlet flange is movable along a length of the body. However, the size of the bore may be smaller than a size of the insert flange, such that the insert flange does not fit through the bore and blocks motion of the outlet flange towards the outlet side of the gas trap insert.

The outlet side of the gas trap insert may thus be connected to the pipeline by attaching the outlet flange to the pipeline. The outlet flange may be attachable to the pipeline by any suitable means. For example, the outlet flange may be attached to the pipeline by clamping the outlet flange to the pipeline, e.g. to a corresponding flange on the pipeline. In another example, the outlet flange may include one or more through-holes, so that it can be bolted to the pipeline, e.g. to a corresponding flange on the pipeline. When the condensate removal device is mounted in the pipeline, the outlet flange presses against the insert flange, which may serve to hold the front surface of the insert flange against the pipeline so that a seal is formed between the insert flange and the pipeline. Thus, a lapped connection may be formed between the insert flange and the outlet flange. The insert flange may have a upstream-facing surface, which is on an opposite side of the insert flange from its downstream facing surface. The annular outlet flange may be configured to press against the upstream-facing surface when the condensate removal device is mounted in the pipeline.

By using the outlet flange, it is not necessary to provide attachment means for attaching the gas trap insert to the pipeline directly on the gas trap insert. Thus,

construction of the gas trap insert may be simplified. This may also improve the flexibility of the condensate removal device, as the outlet flange may be selected based on the desired type of attachment to the pipeline, without having to change any of the other components in the condensate removal device. This configuration also avoids the need to weld the outlet flange to the gas trap insert, which may reduce production costs and facilitate installation and/or removal of the gas trap insert.

The upstream portion of the insert flange may comprise a first engagement feature, and a downstream facing portion of the annular outlet flange that is arranged to engage the upstream portion may comprise a second engagement feature, wherein the first and second engagement features have

complementary shapes. For example, the first engagement feature may be a radially protruding ridge that joins the insert flange to an upstream portion of the gas trap insert. The second engagement feature may be a lip formed around a downstream edge of the bore through the annular outlet flange. When the condensate removal device is mounted in the pipeline, the outlet flange presses against the insert flange and the first and second engagement features are engaged. The first and second engagement features may serve to locate the insert flange relative to the outlet flange (e.g. by centring the insert flange in the outlet flange) , to facilitate connection of the gas trap insert to the pipeline. The first and second engagement features may also serve to improve the mechanical connection between the insert flange and the outlet flange when the condensate removal device is mounted in the pipeline, so that the gas trap insert is securely held in place. The first and second engagement features have complementary shapes, meaning that they are designed to fit together. For example, the first and second engagement features may include male and female portions.

The first engagement feature may be a sloped or curved surface joining the body of the gas trap insert and the insert flange, and the second engagement feature may be a

complementary sloped or curved surface on the lip of the bore. Thus, when the outlet flange presses against the insert flange, the curved or sloped surface on the gas trap insert engages the lip of the bore in the outlet flange.

In some embodiments, the upstream body of the condensate removal device may include a debris filter. In this

configuration, the gas trap insert may be removably attached to an outlet of the debris filter. The debris filter (also known as a "debris strainer") may be arranged to prevent debris carried by the condensable gas or condensate from reaching the condensate drainage channel in the gas trap insert, to avoid blockage of the condensate drainage channel. The debris filter may be a partial barrier through which the condensable gas and condensate flows, but which obstructs the passage of suspended solid matter. Barriers of this type are known, and include cloth, paper and porous porcelain layers. The filter may preferably be a simple mesh, sieve, or

perforated sheet/layer, for example, a basket-type filter.

In some embodiments, the upstream body may further include an inlet flange attached to the debris filter, the inlet flange being attachable to the pipeline to connect the upstream body to the pipeline. The debris filter may be permanently attached to the inlet flange, e.g. they may be welded together, or cast as a single piece. Alternatively, the debris filter may be removably attached to the inlet flange, e.g. via a threaded connection. The inlet flange may be attachable to the pipeline using any suitable means, e.g. by using a clamp mechanism, or by bolting the inlet flange to a corresponding flange on the pipeline. Thus, the upstream body may serve the dual function of connecting the condensate removal device to the pipeline, and removing debris from the flow of condensable gas and condensate, before the flow is delivered to the gas trap insert.

In some embodiments, the inlet side of the gas trap insert may be removably connected to the upstream body by means of a threaded connection. Thus, the inlet side of the gas trap insert and the upstream body may have mating threaded surfaces. This may facilitate connection and disconnection between the gas trap insert and the upstream body, which may facilitate replacement and/or maintenance of the gas trap insert. The threaded connection may form part of the seal between the gas trap insert and the upstream body. For example, the threaded surfaces on the inlet side of the gas trap insert and the upstream body may be configured to form a seal when they are engaged with one another.

In some embodiments, the upstream body of the condensate removal device may include a magnet for capturing magnetic debris carried by the condensable gas or condensate, to prevent the magnetic debris from reaching the condensate drainage channel in the gas trap insert. The magnet may be used on its own or in combination with the debris strainer discussed above. Where both a magnet and a debris strainer are used in the upstream body, the debris filter may preferably be arranged upstream of the magnet. The magnet may be arranged in a similar manner to that describe in GB 2 512 210 A.

In some embodiments, the seal between the gas trap insert and the upstream body may be formed by a gasket that is compressed between the gas trap insert and the upstream body. The gasket may be formed of any suitable compressible material for forming a seal (e.g. PTFE, or a soft metal such as copper or brass) . For example, the gasket may be a fibre washer. The gasket may be compressed between a first sealing face on the upstream body and a second sealing face on the gas trap insert. Using a gasket between the gas trap insert and the upstream body may improve the quality of the seal, enabling the condensate removal device to be used in pipelines having higher pressure ratings. In cases where the connection between the gas trap insert and the upstream body is formed by a threaded connection, the gasket may be compressed by

tightening the threaded connection.

In some embodiments, one of the gas trap insert and the upstream body may include a protrusion having a threaded surface that forms part of the threaded connection between the inlet side of the gas trap insert and the upstream body, and the gasket may be held on the protrusion. Thus, the protrusion serves the double function of connecting the gas trap insert to the upstream body, and holding the gasket in place between the two components so that a seal is formed therebetween. The one of the gas trap insert and the upstream body not having the protrusion, may include an engagement portion in which the protrusion is received. For example, the engagement portion may include a threaded surface that is mated with the treaded surface on the protrusion.

In some embodiments, the condensate removal device may further include a spacer adjacent to the gasket between the gas trap insert and the upstream body. For example, the spacer may be a washer or a shim made of a suitable material (e.g. metal) . Thus, both the gasket and the spacer are held between the gas trap insert and the upstream body, such that the gas trap insert and the upstream body are spaced apart by the gasket and the spacer. This may serve to increase a total length of the condensate removal device. The thickness of the spacer may be selected to adjust the total length of the condensate removal device to a desired length (e.g. so that it fits in a space in the pipeline) . When a spacer is used, the gasket may be compressed between the spacer and a sealing surface on one of the gas trap insert and upstream body, to form a seal at the connection between the gas trap insert and the upstream body. Where one of the gas trap insert and the upstream body include a protrusion having a threaded surface, the spacer may be held on the protrusion adjacent to the gasket. The length of the protrusion may therefore be greater than the combined widths of the gasket and the spacer. An inner surface of the spacer may be threaded, so that the spacer may be threadedly engaged with the threaded surface on the protrusion. In some cases, it may be desirable to shorten the total length of the condensate removal device (e.g. so that it fits in a space in the pipeline) . For example, where the upstream body includes a debris filter, this may be achieved by shortening the debris filter during manufacture of the device (e.g. by machining away a portion of a connection flange on the strainer) .

In some embodiments, the downstream-facing surface of the insert flange may include a groove for receiving a gasket to form a seal with the pipeline. The groove may thus serve to hold the gasket in place to ensure that a seal is properly formed when the condensate removal device is mounted in the pipeline. In other embodiments, the front surface of the insert flange may include a gripping surface for gripping a gasket to form a seal with the pipeline. For example, the gripping surface may include a series of bumps, a series of concentric rings, and/or a roughened surface which act to prevent the gasket from slipping. This may ensure that a seal is properly formed when the condensate removal device is mounted in the pipeline.

In some embodiments, the gas trap insert may include a flattened region (e.g. opposed flat surfaces) configured to provide an engagement portion for a gripping tool. The flattened region may facilitate installation and removal of the gas trap insert, by enabling the body to be firmly gripped with a tool. For example, where the connection between the gas trap insert and the upstream body is a threaded connection, the flattened region may be gripped by a wrench or other suitable tool to apply a torque to the body in order to tighten or loosen the connection.

According to a second aspect of the invention, there is provided a gas trap insert for use in a condensate removal device mounted in a pipeline, the gas trap insert comprising a condensate drainage channel extending between an inlet side and an outlet side of the gas trap insert, wherein the condensate drainage channel includes a constricted passage that is occludable by condensate flow to restrict condensable gas flow through the condensate drainage channel, wherein the inlet side is configured to be removably connectable to an upstream body of the condensate removal device, wherein the outlet side is configured to be directly connectable to a downstream portion of pipeline, and wherein the outlet side comprises a radially protruding insert flange having a downstream-facing surface configured to sealingly abut the downstream portion of pipeline. The condensate removal device in which the gas trap insert is used may be based on the same principles as the condensate removal device of the first aspect of the invention discussed above. Accordingly, features of the first aspect of the invention may be shared by the second aspect of the invention and are not discussed again. In particular, the gas trap insert of the second aspect of the invention may have any of the features discussed above in relation to the gas trap insert of the condensate removal device of the first aspect of the invention. Various types of connection interface may be used, depending on the configuration of the upstream body of the condensate removal device. For example, the connection interface may include a threaded surface, for forming a threaded connection with the upstream body. In another example, the connection interface may include a male or female engagement portion, which is designed to form a connection with a mating part on the upstream body. The connection interface is designed so that a seal may be formed between the inlet side of the gas trap insert and the upstream body when they are connected together. For example, the connection interface may be designed to hold a gasket that is compressed between the gas trap insert and the upstream body when the two parts are connected together.

An advantage of the gas trap insert is that it can easily be connected to and disconnected from the upstream body of a condensate removal device. This may facilitate maintenance of the gas trap insert, as it may be possible to remove the gas trap insert from the pipeline without removing other parts of the condensate removal device. Additionally, the gas trap insert may easily be exchanged due to the removable connection with the upstream body. This may enable multiple different gas trap inserts to be used with a particular upstream body, providing a flexible condensate removal device.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention are discussed below with reference to the accompanying drawings, in which:

Fig. 1 shows a side view of a condensate removal device that is an embodiment of the invention;

Fig. 2 shows a side view of the condensate removal device of Fig. 1, where the internal structure of the device is illustrated by dashed lines;

Fig. 3 shows a first perspective view of the condensate removal device of Fig. 1;

Fig. 4 shows a second perspective view of the condensate removal device of Fig. 1;

Fig. 5 shows an exploded view of the condensate removal device of Fig. 1; Fig. 6 shows a part cutaway view of the upstream body of the condensate removal device of Fig. 1;

Fig. 7 shows a side view of a gas trap insert that is suitable for use in embodiments of the invention;

Fig. 8 shows a side view of the gas trap insert of Fig.

7, where the dashed lines illustrate the condensate drainage passage;

Fig. 9 shows a perspective view of the gas trap insert of Fig. 7;

Fig. 10 shows a side view of the condensate removal device of Fig. 1 when it is mounted in a pipeline;

Fig. 11 shows a first perspective view of the condensate removal device of Fig. 1 when it is mounted in a pipeline;

Fig. 12 shows a second perspective view of the condensate removal device of Fig. 1 when it is mounted in a pipeline.

DETAILED DESCRIPTION; FURTHER OPTIONS AND PREFERENCES

Figs. 1 to 5 illustrate a condensate removal device 100 that is an embodiment of the invention. The condensate removal device 100 is composed of an upstream body 102, a gas trap insert 104 and an outlet flange 106. The upstream body 102 functions as a flow inlet for receiving gas flow from a pipeline, and may be referred to herein simply as a flow inlet. In this example, the upstream body 102 comprises an inlet flange 108 attached to a debris filter 110. The inlet flange 108 includes a sealing surface 112 configured to form a seal with a pipeline when the condensate removal device 100 is mounted in the pipeline. The seal may be formed by placing a gasket on the sealing surface 112, and compressing the gasket between the sealing surface 112 and a corresponding sealing surface on the pipeline when the condensate removal device 100 is mounted in the pipeline. As shown in Figs. 2 to 5, the inlet flange 108 includes a series of through-holes 114. These through-holes 114 serve to bolt the inlet flange 108 to the pipeline, in order to connect the upstream body 102 to the pipeline. For example, the inlet flange 108 may be bolted to a corresponding flange on the pipeline. In other examples, it may not be necessary to provide through-holes 114 in the inlet flange 108, and the inlet flange can be clamped to the pipeline. The upstream body 102 is arranged to receive a flow of condensable gas and condensate (e.g. steam and water) from a pipeline when it is connected to the pipeline. The flow travels into the upstream body 102 through an aperture in an end face thereof. Both the inlet flange 108 and the outlet flange 106 may be configured to connect to the pipeline in a conventional manner, e.g. in line with existing US, European or English standards such as ASME B16.5 or BS EN 1092-1.

The debris filter 110 is located in a flow path along which the condensable gas and condensate flow within the upstream body 102. The debris filter 110 includes a filter sub-chamber 116 which is a hollow region (e.g. a bored region) adapted to receive a filter (not shown) . The filter comprises a perforated (e.g. meshed) sleeve that fits into the filter sub-chamber 116. The sleeve may be held on a perforated reinforcing plate (not shown) to strengthen the sleeve. The flow passes through the perforated sleeve as it traverses the debris filter 110, which thereby restricts the passage of debris that may be contained in the flow of condensable gas and condensate. In this embodiment, the filter sub-chamber 116 is oriented at an oblique angle with respect to the rest of the device 100, making it accessible from the outside via a removable cap 118. The cap 118 may for example be threadedly engaged with a surface of filter sub-chamber 116, so it can be easily removed. The cap 118 may be removed for maintenance of the debris filter 110, e.g. to clean or replace the filter, without removing the whole device 100 from the pipeline. The upstream body 102 may also include one or more magnets arranged to capture magnetic debris contained in the flow. The magnets may either form part of the debris filter 110, or be provided downstream of the debris filter 110.

A more detailed view of the upstream body 102 is shown in Fig. 6, which shows a part cutaway view of the upstream body 102. In the example shown, the inlet flange 108 is welded to the debris strainer 110 at weld joints 120 such that the inlet flange 108 and the debris strainer 110 form a unitary piece. However, in other examples, the debris strainer 110 and inlet flange 108 may be integrally formed, e.g. by casting, forging or machining them as a single part, such that no weld joints are necessary.

After passing through the debris filter 110, the flow path exits the upstream body 102 and enters the gas trap insert 104. The gas trap insert 104 is illustrated in greater detail in Figs. 7-9 (in which the insert is oriented with the flow travelling from left to right) . The gas trap insert 104 includes a body 122 having a condensate drainage channel 124 extending therethrough. The condensate drainage channel 124 provides a fluid flow path between an inlet side 126 of the gas trap insert 104 and an outlet side 128 of the gas trap insert 104. In the example shown, the body 122 is cylindrical, however other shapes may also be used.

The condensate drainage channel 124 is illustrated by the dashed lines in Figs. 2 and 8, and includes a constricted passage 130 (i.e. the narrowest part of the condensate drainage channel 124) which performs the function of the orifice in condensate removal device. In this embodiment, the constricted passage 130 is at the upstream end of the

condensate drainage channel 124, but this is not essential for the invention; it may be formed further downstream in the condensate drainage channel 124. As it extends away from the constricted passage 130 towards the outlet side of the gas trap insert 104, the condensate drainage channel 124 flares open, i.e. it gradually increases in cross-sectional area. In this embodiment, the condensate drainage channel 124 has a circular cross-section, so the increase in cross-sectional area may be achieved by a linear increase in diameter of the condensate drainage channel 124. However, the increase in diameter of the condensate drainage channel 124 need not necessarily be continuous; in some examples it may be a stepwise increase.

When hot condensate is forced through the constricted passage 130 into the condensate drainage channel 124, the pressure drop across the constricted passage causes flash boiling of the condensate, which in turn creates a variable restriction in the flow capacity of the condensate drainage channel 124 which acts to inhibit passage of condensable gas through the constricted passage 130. The diameter of the constricted passage 130, which may be constant, is selected in view of the properties of the pipeline (e.g. differential pressure between the inlet and outlet, composition of the condensable gas, etc.) such that it permits the discharge of condensate at a desired rate. The calculations involved in this selection are the same as for known types of venturi orifice traps.

In this embodiment, the inlet side 126 of the gas trap insert 104 is removably connected to the upstream body 102 by means of a threaded connection. As shown in Figs. 7 to 9, the gas trap insert 104 includes a cylindrical protrusion 132 on its inlet side 126, the cylindrical protrusion 132 having a threaded outer surface 134. The upstream body 102 includes an engagement portion, e.g. a recess for receiving the

protrusion, having a threaded inner surface which cooperates with the threaded outer surface 134 of the protrusion 132. Thus, the gas trap insert 104 can be connected to the upstream body 102 by screwing the protrusion 132 into the engagement portion of the upstream body 102. In alternative examples, the protrusion may be provided on the upstream body 102 and a corresponding engagement portion may be provided on the gas trap insert 104.

The cylindrical protrusion 132 includes an opening 135 (see dashed lines in Fig. 8) which is connected to the condensate drainage passage 124, and which is arranged to receive the condensable gas and condensate flow from the upstream body 102. Because the cylindrical protrusion 132 is threaded within the upstream body, the beginning of the condensate drainage channel may thus between within the upstream body, i.e. being at a location that upstream from the downstream end of the upstream body. This arrangement assists in maximising the length of the condensate drainage channel within the limited size of the insert.

As shown in Fig. 2, a gasket 136 is provided between the upstream body 102 and the gas trap insert 104 in order to form a seal between these two components. The gasket 136 can also be seen in Fig. 5, which shows an exploded view of the condensate removal device 100. The gasket 136 is held on the protrusion 132 of the gas trap insert 104, and is compressed between a first sealing face 138 on the upstream body 102 and a second sealing face 140 on the gas trap insert 104 as the protrusion 132 is connected to the engagement portion. The gasket 136 may be made of any suitable material for making a seal. For example, the gasket 136 may be made out of PTFE, or a soft metal such as copper or brass. The entire outer surface 134 of the protrusion 132 may be threaded, such that the gasket 136 is held on a threaded surface. Alternatively, a portion of the outer surface 134 of the protrusion 132 may be unthreaded (e.g. smooth), such that the gasket 136 is held on the unthreaded portion of the outer surface 134. In other examples, the threaded connection between the protrusion 132 and engagement portion may itself provide a seal.

The body 122 of the gas trap insert 104 includes a pair of flat surfaces 142 on its outer surface that are disposed in a manner to facilitate gripping the body with a tool (e.g. a wrench) . For example, the flat surface 142 may be arranged opposite one another on the outer surface. This arrangement permits the connection between the gas trap insert 104 and the upstream body 102 to be tightened or loosened by gripping the flat surfaces 142 of the body 122 with a tool, and applying a torque to the body 122 via the tool. This may enable a large torque to be applied to the body 122, to ensure that the gasket 136 is sufficiently compressed and forms a seal between the gas trap insert 104 and the upstream body 102 when the connection is tightened.

The outlet side 128 of the gas trap insert 104 includes an insert flange 144 connected to (e.g. integrally formed with) the body 122. The insert flange 144 is configured to directly abut a pipeline, and has a front surface 146 that is arranged to form a seal with the pipeline when the condensate removal device 100 is mounted in the pipeline. The insert flange 144 may be of a standard size to facilitate connection to a pipeline junction. A seal may be formed between the insert flange 144 and the pipeline, for example, by

compressing a gasket between the front surface 146 of the insert flange 144 and the pipeline. In some embodiments, the front surface 146 includes a groove or a gripping surface (not shown), for holding a gasket in place. Thus, the outlet side 128 of the gas trap insert 104 is designed to deliver

condensate directly into the pipeline, and no intermediate components between the gas trap insert 104 and the pipeline are required. In this manner, the condensate removal device 100 defines a flow path for condensable gas and condensate that goes from the upstream body 102 to the outlet side 128 of the gas trap insert 104. Arrow 151 illustrates the direction of condensable gas and condensate flow into the condensate removal device 100. Arrow 153 illustrates the direction of condensate flow out of the condensate removal device 100 (see Figs . 1 , 2 ) .

As can be seen in Fig. 8, the condensate drainage channel 124 begins in the protrusion 132 at the inlet side 126 of the gas trap insert 104, and extends all the way to the outlet side 128 of the gas trap insert 104. Thus, when the gas trap insert 104 is connected to the upstream body (see e.g. Figs.

1, 2) a portion of the condensate drainage channel 124 is located inside the upstream body 102. This enables the length of the condensate drainage channel 124 to be increased (i.e. by the length of the protrusion 132) . This may be

advantageous, as the amount of space available for condensate drainage channels in condensate removal devices is typically quite limited.

The outlet flange 106 serves to secure the outlet side 128 of the gas trap insert 104 to the pipeline. As shown in Fig. 5, the outlet flange 106 is disc-shaped and has a central bore 148. The bore 148 is sized so that the body 122 of the gas trap insert 104 can pass through the bore 148, such that the outlet flange 106 can be moved along the length of the body 122. In the example shown, the body 122 is cylindrical, so the diameter of the bore 148 is slightly larger than an outer diameter of the body 122 to enable the body 122 to fit through the bore 148. The insert flange 144 is larger than the bore 148, i.e. a diameter of the insert flange 144 is larger than the diameter of the bore 148. Thus, the insert flange 144 blocks motion of the outlet flange 106 towards the outlet side 128 of the gas trap insert 104, i.e. the outlet flange 106 abuts against the insert flange 144 when the outlet flange 106 is moved along the body 122 towards the outlet side 128 of the gas trap insert 104.

The gas trap insert 104 includes a curved surface 150 joining the body of the gas trap insert 104 to the insert flange 144. The curved surface 150 provides a smooth

connection between the body 122 and the insert flange 144, and forms a ring around the circumference of the body 122. A lip 152 of the bore 148 in the outlet flange 106 has a curved surface that is complementary to the curved surface 150 on the gas trap insert 104. In this way, when the outlet flange 106 is moved along the body 122 so that it abuts against the insert flange 144, the lip 152 of the bore 148 in the outlet flange 106 engages the curved surface 150 of the gas trap insert 104. Thus, the lip 152 and the curved surface 150 act as engagement features between the gas trap insert 104 and the outlet flange 106. In alternative embodiments, different types of engagement features may be used. For example, a sloped surface or any other suitable shape may be used instead of a curved surface.

When the condensate removal device 100 is mounted in the pipeline (see Figs. 10-12 and discussion below), the outlet flange 106 is attached to a corresponding flange on the pipeline, so that it presses against the insert flange 144 to secure the insert flange 144 to the pipeline and form a seal with the pipeline. The outlet flange 106 presses against a rear surface 147 of the insert flange 144, the rear surface 147 being on an opposite side of the insert flange 144 compared to its front surface 146. In this situation, the curved surface 150 of the gas trap insert 104 and the lip 152 of the bore 148 in the outlet flange 106 are engaged with one another, as illustrated by the dashed lines in Fig. 2. The engagement features (i.e. the curved surface 150 and the lip 152) serve to provide strong mechanical connection between the gas trap insert 104 and the outlet flange 106, e.g. due to the increased contact area between the gas trap insert 104 and the outlet flange 106. This may serve to ensure that the gas trap insert 104 is securely held in place when the condensate removal device 100 is mounted in the pipeline. Additionally, the engagement features may ensure that the body 122 of the gas trap insert 104 is centrally located within the bore 148 of the outlet flange 106, so that the gas trap insert 104 is correctly positioned when the condensate removal device 100 is mounted in the pipeline. The mechanical connection between the gas trap insert 104 and the outlet flange 106 may be

considered as a lapped connection, as it is provided by overlapping parts (namely the insert flange 144 and the outlet flange 106).

The outlet flange 106 includes a series of through-holes 154 for bolting the outlet flange 106 to the pipeline, in order to connect the outlet side 128 of the gas trap insert 104 to the pipeline. For example, the outlet flange 106 may be bolted to a corresponding flange on the pipeline. In other examples, it may not be necessary to provide through-holes in the outlet flange 106, and the outlet flange 106 can be clamped or otherwise secured to the pipeline.

Figs. 10-12 illustrate the condensate removal device 100 of the embodiment when it is mounted in a pipeline 156. The pipeline 156 has an inlet side 158 that delivers a flow of condensable gas and condensate (e.g. steam and water) to the upstream body 102 of the device 100, and an outlet side 160 which receives condensate from the outlet side 128 of the gas trap insert 104. Arrow 174 illustrates the direction of condensable gas and condensate flowing through the pipeline 156 into the condensate removal device 100. Arrow 176

illustrates the direction of condensate flowing out of the condensate removal device 100 back into the pipeline 156. The inlet flange 108 of the condensate removal device 100 is attached to a first flange 162 on the inlet side 158 of the pipeline 156, by means of bolts 164 and nuts 166. The bolts 164 pass through through-holes 114 in the inlet flange 108 and corresponding through-holes in the first flange 162. In other examples, it may not be necessary to use bolts 164 and nuts 166, and a clamp may be used instead. A gasket (not shown) is compressed between the sealing surface 112 on the inlet flange 108, and a corresponding sealing surface on the first flange 162 of the pipeline 156, to form a seal between the upstream body 102 and the inlet side 158 of the pipeline 156.

The outlet side 128 of the gas trap insert 104 is connected to the outlet side 160 of the pipeline 156 by attaching the outlet flange 106 to a second flange 168 on the outlet side 160 of the pipeline 156. The outlet flange 106 is attached to the second flange 168 by means of bolts 170 and nuts 172, the bolts passing through through-holes 154 in the outlet flange 106 and corresponding through-holes in the second flange 168. In other examples, it may not be necessary to use bolts 170 and nuts 172, and a clamp may be used instead. The bolts 170 are tightened so that the outlet flange 106 presses against the insert flange 144, to hold the front surface 146 of the insert flange 144 against a corresponding sealing surface on the second flange 168 of the pipeline 156.

A gasket (not shown) is compressed between the front surface 146 of the insert flange 144 and the sealing surface on the second flange 168 of the pipeline 156, to form a seal between the gas trap insert 104 and the outlet side 160 of the pipeline 156.

A flow of condensable gas and condensate flowing through the pipeline 156 may thus enter into the upstream body 102 of the device from the inlet side 158 of the pipeline. The flow passes through the debris filter 110 in the upstream body 102, where debris or solid matter suspended in the flow remain trapped. The flow then passes into the gas trap insert 104 where the condensate drainage channel 124 allows the passage of condensate, but prevents the passage of condensable gas.

The condensate may then exit from the outlet side 128 of the gas trap insert where it is returned directly to the outlet side 160 of the pipeline 156.

The condensate removal device 100 may be designed to have a predetermined length from the sealing surface 112 on the inlet flange 108 to the front surface on the gas trap insert 104. For example, the condensate removal device 100 may be designed so that the predetermined length is a standard length, to facilitate its installation in a pipeline. The length of the condensate removal device 100 may be adjustable so that a single device can be configured with any one of a plurality of predetermined lengths. For example, a spacer (e.g. a washer or shim) may be mountable between the upstream body 102 and the gas trap insert 104, adjacent to the gasket 136, in order to extend the length of the device whilst still enables the gasket 136 to be compressed to provide a seal. The spacer may thus be held on the protrusion 132 of the gas trap insert 104, next to the gasket 136. The spacer serves to increase the spacing between the upstream body 102 and the gas trap insert 104, such that the total length of the condensate removal device 100 is increased by an amount corresponding to the thickness of the spacer.

As the gas trap insert 104 and the upstream body 102 are removably connected to one another, the gas trap insert 104 may be removed from the pipeline 156 without having to remove the upstream body 102 from the pipeline 156. For example, the gas trap insert 104 may be removed by undoing bolts 170 and nuts 172, and then rotating the body 122 of the gas trap insert 104 to undo the threaded connection between the gas trap insert 104 and the upstream body 102. This enables the gas trap insert to be easily removed for maintenance (e.g. cleaning of the condensate drainage channel 124) or replacement .