Samson 45-1N Differential Pressure Regulator DN 15

Samson 45-1N self-operated differential pressure regulator

The Samson Type 45-1N (written 45-1 N in the manufacturer data sheet) is a compact differential pressure regulator for heating systems. It holds the pressure difference between the flow and return pipes of a pipeline section at a fixed value and protects the section from inadmissible differential pressure when thermostatic valves close. The regulator is a valve with an integrated actuator and needs no auxiliary energy. Seven Star LLC supplies Samson 45-1N regulators in Oman and the GCC as an independent supplier in Muscat.

Decoding the 45-1N and its sister Type 45-3 N

Samson covers two versions in one data sheet (T 3140 EN), and the difference is where the valve is installed:

• Type 45-1 N: fixed set point, designed for installation in the high-pressure pipe, for example the flow pipe.
• Type 45-3 N: fixed set point, designed for installation in the low-pressure pipe, for example the return pipe.

Both have a closing actuator, so the valve closes as the differential pressure rises. Both are DN 15 with an ISO 228/1 G¾ B connecting thread on each side, to which G½ threaded ends or welding ends are fitted as accessories. An ANSI version is available on request.

Technical specifications of the Type 45-1N

How the 45-1N controls differential pressure

The medium flows through the valve body. In the 45-1N the pressure at the valve outlet, the high pressure, acts on the high-pressure side of the operating diaphragm through the control line that is permanently attached to the regulator. The low pressure reaches the other side of the diaphragm through an external control line that is fitted during installation, plus a hole in the valve body. The set point spring inside the valve defines the differential pressure at which the diaphragm balances.

When the differential pressure in the pipeline section rises, for example because a thermostatic valve closes, the force on the high-pressure side grows. The plug, connected to the diaphragm by the plug stem, moves toward the seat and throttles the valve. When a thermostatic valve opens and the differential pressure falls, the spring pushes the plug open again. The behaviour is purely proportional and continuous, with no electronics.

Materials and construction of the 45-1N

The valve is a single-seated design with a soft-seated, unbalanced plug, which explains the tight Class I leakage figure. The complete regulator weighs only about 0.65 kg, so it needs no special lifting or support.

Where the 45-1N fits in a heating network

The regulator is described by Samson as especially suitable for local heat supply networks, and it is also used in larger heating networks. Typical positions are at the branch to a building, a riser or a group of radiators. By limiting the differential pressure, the 45-1N keeps the thermostatic radiator valves in their proper control range and prevents flow noise. The 45-3 N is the alternative where the designer wants the regulator in the return line, while the 45-1N goes in the flow line. In both cases the two control lines must be connected so that one side of the diaphragm sees the flow-side pressure and the other the return-side pressure.

Selection and ordering checklist for the 45-1N

• Version: 45-1 N for the high-pressure (flow) pipe, or 45-3 N for the low-pressure (return) pipe.
• Fixed differential pressure set point: 0.15 bar or 0.3 bar, or an agreed alternative.
• Required flow rate, to compare against the KVS value of 2.5 and the 4 bar maximum differential pressure.
• Medium and maximum temperature: treated water up to 110 °C, non-flammable gas up to 80 °C.
• End connections: G½ threaded ends or welding ends, supplied as accessories, for both sides of the valve.
• Operating pressure against the PN 10 rating.
• Quantity and the pipe positions on the project drawing.

The ordering text in the data sheet is short: the regulator type, the differential pressure set point in bar, and the accessories with G¾ connecting threads and G½ threaded or welding ends.

Installation and maintenance of the 45-1N

Install the valve in a horizontal pipeline with the flow direction matching the arrow on the body, and preferably with the actuator suspended downward. Fit the external control line according to the diagram in the data sheet, taking care that the line from the flow side and the line from the return side are not interchanged. Flush the network before fitting the valve so that scale does not reach the seat. As a low-maintenance regulator without auxiliary energy, it mainly needs checking for leaks at the connections, damage to the control line and a fouled seat if the pipe contains debris.

Typical applications in Oman and the GCC

Hot-water heating is a smaller market in the Gulf than chilled water, but it exists in hospitality and healthcare buildings, laundries, swimming pool and process-heat circuits, and district or campus systems where hot water is distributed. Differential pressure regulation is just as relevant for these loops as in colder countries, because variable flow from thermostatic or zone valves changes the pressure across branches. The compact DN 15 size of the 45-1N suits apartment-level or small branch applications in such buildings.

Information to send with your RFQ for the 45-1N

Please state the version (45-1 N or 45-3 N), differential pressure set point, medium and temperature, flow rate per regulator, end connection type and quantity. If the regulator is for a replacement, add the nameplate data of the existing unit.

Documents and quotation

A Samson datasheet for the 45-1N and the 45-3 N (T 3140 EN) is attached on this page for download.

Send the part number 45-1N and your project data, and we will prepare a quotation for Oman and the GCC.