APT10-4.5 automatic pump trap

1. Safety information

Safe operation can only be guaranteed when the product is properly installed, commissioned, used and maintained by qualified personnel in accordance with these instructions. Follow the general installation and safety rules for pipeline and plant construction, and use tools and safety equipment correctly.

Intended use and limits

Check the Installation and Maintenance Instructions, Technical Information Sheet and name-plate to confirm suitability for the intended application. The product meets the PED and ATEX 2014/34/EU requirements as applicable. The PED classification in this guide is SEP for Group 2 gases and Group 2 liquids. The ATEX marking is II 2G CT3.

• The product is specifically designed for Group 2 steam, air and water/condensate. Contact Spirax Sarco before considering another fluid.

• Confirm material suitability and system pressure and temperature limits. Where a product limit is lower than the possible system condition, or a failure could create dangerous overpressure or overtemperature, provide a suitable safety device.

• Determine the correct installation position and fluid-flow direction. Prevent external system stresses from acting on the product, and remove connection protection covers before installation.

Workplace and system safety

• Provide safe access, a guarded working platform where necessary, adequate lighting and suitable lifting gear.

• Consider the present and previous pipeline contents, including flammable or health-hazardous substances and temperature extremes. Assess the surrounding environment for explosion risk, oxygen deficiency, dangerous gases, hot surfaces, fire, noise and moving machinery.

• Before an action such as isolating a valve, consider its effect on the complete system and other personnel. Do not disable vents, protective devices, controls or alarms. Operate isolation valves gradually to avoid system shocks.

• Isolate pressure and vent it safely to atmosphere. Consider double block and bleed and locking or labelling closed valves. A zero reading on a pressure gauge is not proof that the system is depressurised.

• After isolation, allow temperature to normalise before work. Use suitable tools, consumables and genuine Spirax Sarco replacement parts. Assess the need for protective clothing for chemical, temperature, radiation, noise, falling-object, eye and face hazards.

• Work must be performed or supervised by a competent person. Follow a formal permit-to-work system where one exists, and use warning notices or a dedicated safety assistant where required.

• Assess manual-handling risk from the task, person, load and working environment. The product surface can reach 200 °C (392 °F) at maximum permitted operating conditions. The product is not self-draining, so take care when dismantling or removing it and protect it against freezing where relevant.

• The product contains no hazardous construction materials and can be recycled or disposed of responsibly. When returning it, provide written information about contamination residues, mechanical damage and relevant safety data.

2. General product information

Description

The APT10-4.5 is a PN10 displacement receiver with a standard blue paint finish or ENP (electroless nickel plate). Depending on line conditions, it automatically traps or pumps. It is operated by steam and removes condensate from process and heating plant under all pressure conditions, including vacuum.

Sizes, connections and limiting conditions

BSP - BS 21 parallel / BSP and NPT / NPT connection arrangements are documented.

Technical specification and order definition

Establish the available installation head, motive-steam pressure, total return backpressure, heat-exchanger full-load operating pressure and maximum steam load, and the secondary fluid's minimum and maximum controlled temperatures. The guide gives a DN20 x DN20 pump discharge per cycle of 2.1 litres. Order example: one APT10-4.5 automatic pump trap with screwed DN20 x DN20 BSP connections and BSP motive-fluid connections.

The technical-information document TI-P612-28 states a 2.6 litre per-cycle figure. The source documents are retained separately; this manual preserves its own stated 2.1 litre value rather than presenting an unsupported combined value.

Dimensions are approximate and in mm unless stated otherwise.

Materials

The cover and body are SG iron to EN JS 1025 / ASTM A395. The cover gasket in this guide is graphite laminated with a stainless-steel insert. The cover bolts, pump-trap lever, float, pivot shaft, washer, trap housing, ball, inlet-check-valve seat and flap, pump-mechanism bracket, spring, split pin, exhaust seat, inlet and exhaust valves, valve-seat gasket, mechanism and float bolts, first-stage valve, trap gasket, actuator arm, name-plate and drain plug are specified as stainless-steel items. The detailed material schedule uses BS EN ISO 3506 Gr. A2-70, BS 1449 304 S15, BS 1449 304 S16, BS 970 431 S29 / ASTM A276 431, BS 1449 316, ASTM A276 440 B, BS 3146 ANC 4B, BS 2056 302 S26 Gr. 2, BS 1574, BS 3146 ANC 2, BS 1449 409 S19 and DIN 17440 1.4571 where applicable. The motive-supply strainer is SG iron.

There are no hazardous materials in the construction. Recycle or dispose of unwanted material in an environmentally responsible way.

3. Installation

Important safety note: Before installation or maintenance, isolate all steam and condensate lines, relieve residual pressure, let hot parts cool, wear suitable protective clothing and use suitable lifting gear with the product secured. When pumping a potentially explosive medium, the motive medium must be an inert gas containing no oxygen.

3.1 Inlet piping

Size inlet pipework so it can accumulate condensate during the discharge cycle and prevent condensate backing up into the drained equipment. A pipe length and diameter that accommodates 2.1 litres is generally sufficient. Position the condensate reservoir at least one pipe diameter below the process outlet but as high as possible above the APT10-4.5 inlet. Fit a Spirax Sarco Y-type strainer with a maximum 0.8 mm perforation screen at the condensate inlet.

Maintain the 250 mm minimum withdrawal distance shown in Fig. 4 for the motive-supply and exhaust-line coupling.

3.2 Installation head

Install with at least 0.3 m (12 in) head from the base of the unit where possible. The minimum is 0.2 m (8 in), with reduced capacity. At cold start-up, hydraulic pulsing of the inlet check valve can occur; in that case, install a throttling isolation valve to reduce filling pressure.

3.3 Connections

Connect the DN20 port marked IN to the outlet of the drained equipment and the DN20 port marked OUT to the condensate return. Follow the flow arrow. Connect the DN15 port marked S to a trapped motive-steam supply, drained of condensate at all times by a steam trap and filtered through the supplied 100-mesh strainer. Connect the screwed DN15 port marked E as an exhaust balance line as close as possible to the condensate outlet of the drained equipment. The balance line must always connect to the top of the condensate pipe. The unit can be secured to a level, stable surface through the two 12 mm holes in the cover base.

3.4 Outlet piping

Size the outlet piping to prevent excessive APT10-4.5 backpressure, taking account of flash-steam effects at the heat exchanger's full-load operating condition.

4. Commissioning

1. After connecting the inlet, outlet, motive-steam and exhaust connections in accordance with the installation arrangement, slowly open the motive-steam inlet to pressurise the APT10-4.5. Keep the exhaust / balance line open and unrestricted.

2. Slowly open the isolation valves in the condensate inlet and discharge lines, allowing condensate to fill the body.

3. The APT10-4.5 is then ready to operate.

4. When the process plant is operating, the unit discharges condensate into the return line under all pressure conditions. If an irregularity is observed, recheck the installation; if it still fails to operate, use the fault-finding guide.

5. Operation

Step 1: trapping with sufficient differential pressure

The unit uses positive displacement. Condensate enters through the inlet swing check valve and raises the float. The float connects to the trap mechanism through a lever-and-pivot arrangement. When upstream system pressure PS is sufficient to overcome backpressure PB, condensate discharges through the opening trap mechanism. The float modulates with incoming condensate and controls trap opening and closure.

Step 2: a conventional trap would stall

On temperature-controlled equipment, PS can become lower than PB. A standard trap can then stall and allow condensate to flood the drained equipment.

Step 3: automatic changeover begins

With the APT10-4.5, condensate fills the main chamber and raises the float until the changeover linkage engages. The linkage opens the motive inlet and closes the exhaust valve.

Step 4: pressure-powered discharge

The snap-action mechanism changes rapidly from trapping to active pumping. With the motive inlet open, body pressure rises above total backpressure and condensate is forced through the trap seat into the plant return system.

Step 5: return to exhaust condition

As the condensate level falls, the float re-engages the changeover linkage. The motive inlet closes and the exhaust valve opens.

Step 6: refill and repeat

With the exhaust valve open, body pressure equalises with condensate inlet pressure. Condensate re-enters through the inlet swing check valve. The outlet ball check valve prevents return flow into the main chamber, and the trapping or pumping cycle returns to Step 1.

6. Maintenance and spare parts

Important: Isolate and depressurise all steam and condensate lines, allow hot parts to cool, wear suitable safety clothing, secure the unit and use lifting gear. Take care of the snap-action mechanism when dismantling.

Mechanism inspection and cover removal

Use a 19 mm A/F socket, flat-blade screwdriver and torque wrench. Disconnect the cover connections, remove the cover bolts and slide the body away from the cover, allowing at least 135 mm withdrawal distance. Clamp the cover assembly on a suitable bench without damaging the gasket face. Inspect the mechanism for damage, dirt, scale and free float movement. Check the spring assembly, valve movement, exhaust-valve guide, float condition, inlet swing-check movement and sealing faces. Inspect the integral trap module for debris. The outlet check valve cannot be inspected without removing the trap module.

When fitting a new cover assembly, clean the body gasket face, align a new gasket without pinching it, then tighten cover bolts sequentially in opposing pairs to 63 +/- 5 N m using the M12 x 40 bolts and a 19 mm A/F socket. Reconnect S and E, then IN and OUT, and recommission in accordance with Section 4.

Available spares

Spares are supplied in kits to include associated replacement parts. Refer to the technical-information spare-parts diagram for component locations and state the unit size and type when ordering.

7. Replacement of cover, inlet check, spring and float parts

Apply the safety precautions in Section 6 before every procedure. Use new split pins and washers where specified, keep sealing faces clean, align every gasket without trapping it, reconnect all ports to their correct markings, and recommission after reassembly.

7.1 Cover gasket

1. Disconnect the cover, remove the bolts with a 19 mm A/F socket, slide the cover assembly clear by at least 135 mm and secure it without contacting the gasket face.

2. Remove old gasket material without damaging body or cover sealing faces.

3. Fit a new gasket, align the cover and tighten M12 x 40 cover bolts in opposing pairs to 63 +/- 5 N m.

4. Reconnect motive and exhaust lines to S and E, then condensate inlet and outlet to IN and OUT.

7.2 Inlet swing check valve

1. Remove the cover and old gasket as above, and secure the cover assembly.

2. Remove the circlip from the steam inlet valve, then remove the three M8 pump-mechanism-bracket bolts with a 13 mm A/F socket.

3. Lift the bracket assembly away without allowing its spring to bend back on itself. Remove the check-valve flap.

4. Fit a new flap with clean, undamaged flap and seat faces. Reassemble in reverse order, tighten the three M8 bolts to 18 +/- 2 N m and fit a new circlip before closing the cover.

7.3 Spring and actuator arm

1. Remove the cover and set the float at the bottom of its travel.

2. Remove the split pin and washer from the spring-retaining shaft, remove the shaft and let the spring assembly drop free.

3. Draw the actuator arm down in its slots. If required, move the exhaust valve against its internal spring to free it from the bracket guide. Remove the exhaust valve from the actuator-arm spigot without losing the small compression spring.

4. Fit the new spring and actuator arm in reverse order. Compress the small exhaust-valve spring before fitting it to the actuator-arm spigot, make sure the actuator sits in the bracket slots and the exhaust valve slides freely. Use new split pins and washers.

7.4 Float and lever

1. Remove the cover and first remove the spring-retaining shaft, split pin and washer. This must be done before removing the trap-pivot shaft so that the spring is not overstressed.

2. Remove the trap-pivot shaft, then the pump-pivot shaft. To remove the pump-pivot shaft, remove the three M8 bracket bolts and the steam-inlet-valve circlip and separate the bracket from the cover.

3. Remove the float and lever assembly. The replacement kit supplies these assembled.

4. Reassemble using new split pins and washers in this sequence: 52 mm pump pivot shaft X, refit the bracket and tighten its M8 bolts to 18 +/- 2 N m, then 40 mm trap pivot shaft Z, then 30 mm spring retainer shaft Y after aligning the spring and actuator arm. Refit a new circlip to the steam inlet valve.

5. Move the float through its upper and lower limits. The mechanism must move smoothly and snap over to operate the motive inlet and exhaust valves. The valve gear is adjustment-free; if it does not operate, check the alignment and assembly.

8. Replacement of trap, check-valve and steam-valve parts

8.1 Trap and outlet check-valve mechanism

1. Remove the cover, clean off old gasket material and fit a new body gasket.

2. Remove the split pin, washer and trap-pivot shaft. Remove the trap valve stem and swing the float and lever up for access.

3. Using a 24 mm A/F socket, unscrew the trap and check-valve housing and withdraw the complete assembly. There are no serviceable parts within it; the replacement kit contains new parts.

4. Clean sludge and scale from the trap-housing bore. Fit a new trap gasket and install the replacement assembly in reverse order.

5. Tighten the trap housing to 125 +/- 7 N m. Refit the trap valve stem and 40 mm trap-pivot shaft with new split pins and washers. Confirm that float movement gives smooth trap-stem travel.

6. Refit the cover and tighten M12 x 45 cover bolts in opposing pairs to 63 +/- 5 N m before reconnecting the ports and recommissioning.

8.2 Steam inlet and exhaust valves and seats

1. Remove the cover and old gasket, secure the cover assembly, remove the inlet-valve circlip and then the three M8 bracket bolts.

2. Lift the bracket without bending its spring. With a 24 mm deep-series socket, remove both steam inlet and exhaust seats. Remove the seats, metal gaskets and steam inlet valve.

3. Clean the threads and gasket faces. Install the replacement inlet valve assembly and exhaust valve, using a new metal gasket on the seat thread. Tighten each seat to 125 +/- 7 N m.

4. Refit the pump bracket and tighten its three M8 bolts to 18 +/- 2 N m. Fit a new inlet-valve circlip.

5. To replace the exhaust valve, remove the split pins, washers and 30 mm spring-retaining shaft, release the spring assembly, remove the actuator arm and remove the exhaust valve from its spigot. Fit the replacement in reverse order, compressing its small spring before it is fitted to the spigot.

6. Align the actuator in the bracket slots, confirm free exhaust-valve movement and use new split pins and washers. Move the float through its limits to confirm snap-over and valve opening/closing. Refit the cover, tighten the bolts to 63 +/- 5 N m, reconnect correctly and recommission.

9. Fault finding

Caution: Installation and fault finding must be performed by qualified personnel. Before maintenance, relieve residual pressure, let hot parts cool, wear suitable protective clothing, use lifting gear and take care of the snap-action mechanism.

Check these conditions first

• All isolation valves are open.

• The condensate-inlet strainer is clean and free of debris.

• The available installation head exceeds 0.2 m from the pump base.

• Available motive pressure is higher than total backpressure and does not exceed 4.5 bar g.

• The E exhaust balance line connects to the drained-equipment outlet and is unobstructed.

• Flow direction matches the arrow on the unit.