FOREACH miniature diaphragm pumps for OEM integration: operating points, instrument validation and production introduction
Whether the miniature diaphragm pump can work stably in OEM instruments depends on the joint matching of fluid path tasks, inlet and outlet conditions, material combinations, control methods and overall machine structure. Taking FOREACH DPL30, DPL60, DPL30H and DPGL800 as examples, this article starts from the flow and pressure budget, gas-liquid status, wetted materials and electrical interfaces to explain how to establish candidate solutions, carry out reproducible prototype verification, and convert the verification results into technical requirements for production supply.
An analyzer may need to complete cleaning fluid replenishment, reaction chamber flushing, waste liquid discharge and pipeline priming at the same time. These actions are all related to fluid transportation, but the requirements for pumps are different: cleaning focuses on the terminal flow rate and coverage effect, extraction focuses on the recovery ability when containing gas, thin tube liquid supply focuses on the working point under back pressure, and long-term circulation also requires attention to temperature rise and lifespan. Selecting a flow rate is only the first step in OEM integration.
The OEM integration mentioned in this article refers to the selection, adaptation and verification of the FOREACH miniature diaphragm pump as an internal component of the instrument. Standard models, optional configurations and project customization should be confirmed separately. The deliverables of technical work should include complete models, fluid circuit boundaries, electrical and mechanical interfaces, acceptance methods and change requirements, so that R&D, procurement, production and after-sales use the same basis.
The following product values are based on the FOREACH Chinese specifications listed at the end of the article; the calculation examples are used to explain the design method and do not represent the actual measurement results of a certain model. The actual reagents, mixed media, special installation and cycle-time requirements should be verified in the corresponding configuration and the complete instrument fluid path.
1. Convert equipment actions into verifiable pump requirements
If the demand table only says "24 V, 300 mL/min, self-priming", the supplier still cannot determine under what conditions this flow rate needs to be achieved. You should first describe where the liquid comes from and where it goes, what components are before and after the pump, how the liquid level and pressure change, and then define the completion standards of the action.
| Device tasks | Conditions that require quantification | Suggested observations |
|---|---|---|
| Cleaning fluid supply and cavity flushing | Each volume, effective liquid supply time, concurrent branch, nozzle or valve group resistance | Actual liquid supply volume at the end, distribution of each branch, cleaning coverage and residue |
| Reagent or buffer assisted delivery | Medium composition, concentration, temperature, target flow rate, allowed bubbles and pulsation | Liquid supply stability, medium changes, and bubbles entering the downstream |
| Circulation | Circulation flow, circuit resistance, running time, liquid storage volume | Temperature rise, liquid level change, flow drift and medium stability |
| Waste liquid extraction and pipeline emptying | The order in which liquid and air enter, residual liquid volume, suction height, discharge end pressure | Completion time, residual liquid, recovery after gas ingestion, and backflow after shutdown |
| High back pressure liquid supply | Filter load, terminal pressure, maximum transient pressure | Flow rate, temperature rise and pressure bearing capacity of the entire liquid line under target back pressure |
A distinction should also be made between conveying and metering. If the process requires a defined accuracy in the volume delivered each time, simply setting the diaphragm pump run time does not automatically result in a reliable dosing system. Start-stop transients, pipeline elasticity, valve seals, back pressure, and air bubbles will all change the actual liquid output of an action; the role of calibration, flow feedback, or other metering components needs to be evaluated.
It is recommended to write the normal status and boundary status into the requirements at the same time: full bottle and low liquid level, initial dry pipe and wetted pipe, new filter and filter close to replacement condition, single branch and multi-branch opening at the same time, cold and warm startup. This creates a testable working range rather than an isolated parameter point.
2. Evaluating four FOREACH diaphragm pump series for an OEM shortlist
The specifications of DPL30, DPL60 and DPL30H are based on purified water as the working medium, and require other liquids to be evaluated by customers; the working medium of DPGL800 is listed as gas and gas-liquid mixture. When selecting a model, you should first clarify the medium status, and then compare the corresponding flow and pressure conditions.
| Series | Key datasheet parameters | OEM evaluation direction and boundaries |
|---|---|---|
| DPL30 liquid diaphragm pump | free flow 300 mL/min; rated pressure 100 kPa; self-priming height 6 mH₂O | Liquid supply, cleaning and small liquid line transportation; target flow rate needs to be verified under actual suction conditions and back pressure |
| DPL60 liquid diaphragm pump | free flow 600 mL/min; rated pressure 100 kPa; self-priming height 3 mH₂O | Cleaning, circulation and drainage requiring greater liquid delivery; higher free flow does not guarantee that every fluid path will complete its task in half the time |
| DPL30H high pressure liquid diaphragm pump | free flow 300 mL/min; rated pressure 600 kPa; self-priming height 3 mH₂O | Liquid supply, filtration and flushing of higher back pressure; 300 mL/min and 600 kPa are indicators under different conditions |
| DPGL800 gas/liquid diaphragm pump | Single head no-load gas flow 6 L/min; maximum positive pressure 30 kPa; maximum negative pressure < −90 kPa | Gas and mixed gas/liquid aspiration, vacuum generation and evacuation; 6 L/min is not a liquid flow rating, and dual-head capacity cannot simply be stated as 12 L/min |
DPL30, DPL60 and DPL30H list 12 V / 24 V and brushed/brushless versions. The standard selection table in this DPGL800 datasheet revision lists a 24 V brushless configuration. Characters in an ordering-code explanation describe configuration options; they do not establish that every possible combination is an available standard model.
3. Derive the target flow from cleaning volume and equipment cycle time
First calculate the average flow required for the action, and then check whether the pump can achieve it in the actual fluid circuit. If 30 mL needs to be delivered for one cleaning and the actual time left for liquid delivery is 15 s, the required average flow rate is 120 mL/min. Valve switching, start-up delay, priming and waiting time for liquid to reach the end should be deducted separately from the total action window.
Q_req = 60 × V / t_effThe unit of Q_req is mL/min, V is the volume that needs to be delivered to the end (mL), and t_eff is the effective delivery time (s). Example: 60 × 30 / 15 = 120 mL/min.If four branches are opened at the same time, the total demand should be determined based on the sum of the flow rates of the branches working at the same time; if they are flushed one by one in time sequence, the total demand should be calculated in time sequence. Simply adding the rated flows of all branches will conceal the actual concurrent relationship, and may also cause the pump to be in an unnecessary high flow state for a long time. Conversely, only verifying the total flow rate without measuring each branch may miss insufficient fluid supply in branches with greater resistance.
Flow margin should cover identifiable sources of variation
Margins are provided to cover batch differences, media viscosity changes, filter loading, liquid level drops, power supply fluctuations and performance drift after use. Identify how these factors change the pump curve or system resistance before deciding how much margin is needed. Adding a uniform percentage to all equipment is not a substitute for verification of boundary conditions.
M_Q = (Q_available,worst − Q_req) / Q_req × 100%Q_available,worst is the flow rate available under the defined most adverse working conditions, which should be derived from the curve or test of the corresponding working conditions. If the actual measurement in the example is 150 mL/min and the demand is 120 mL/min, the margin is 25%; the 150 mL/min here is an assumed value, not a guaranteed value for a certain FOREACH model.The maximum allowed flow rate should also be given. Some nozzles, reaction chambers or liquid level detection structures may cause splashing, foaming or false triggering due to excessive flow. Meeting the minimum demand is evaluated together with the need to control the maximum flow rate, using appropriate speed control, valve control or feedback schemes where necessary.
4. Establish a pressure budget and check the suction end and discharge end respectively.
Liquids create pressure drops as they pass through pipes, joints, valves and filters, and pressure is also required to overcome liquid level differences. For a given flow rate, the required pressure differential of the system can be established first, and then compared with the performance of the pump under the same medium, power supply and speed conditions.
Δp_pump = (p_dest − p_source) + ρg(z_dest − z_source) + ΣΔp_lossThis equation is used for system pressure budgets for steady-state, incompressible liquids and ignores or otherwise accounts for endpoint velocity head differences. The pressure takes the same reference standard, and the unit is Pa; ρ is kg/m³, g is m/s², and z is m. Pressure drop should be calculated or measured at the target flow rate.In addition to the total pressure difference, the individual pressure conditions at the pump inlet and outlet must also be preserved. When there is negative pressure at the inlet and back pressure at the outlet, the filling and discharging of the pump chamber will be affected at the same time. If the specification curve tests the suction negative pressure and discharge positive pressure respectively, the negative pressure section and the positive pressure section cannot be randomly spliced to infer the accurate flow rate after both ends are loaded at the same time.
Example of a pressure budget for a 120 mL/min cleaning fluid line
Assuming an approximate water medium, the source liquid level is connected to the atmosphere, the pump is 0.5 m higher than the source liquid level, and the end is 0.5 m higher than the pump. The following piping, filter, and terminal pressures are assumed design inputs at the target flow rate and are used to demonstrate calculations only.
| Pressure-budget item | Example values | Design implication |
|---|---|---|
| Height difference from source liquid level to pump inlet | About 4.9 kPa | Reduce inlet gauge pressure; low fluid levels require rechecking |
| Pressure drop through the suction line and fittings | 3 kPa | Together with the height difference, the pump inlet pressure is determined |
| Height difference from pump outlet to end | About 4.9 kPa | Increase the pressure required at the outlet |
| Pressure drop through the discharge line and valve manifold | 8 kPa | Counted according to the actual open flow path |
| Filter pressure drop | 6 kPa when clean; 20 kPa at the replacement threshold | Cover filter loading up to a defined replacement condition |
| Terminal vessel gauge pressure | 15 kPa | Included as destination pressure boundary |
At the filter replacement threshold, pump inlet gauge pressure is approximately −7.9 kPa, required outlet gauge pressure approximately 47.9 kPa, and differential pressure across the pump approximately 55.8 kPa. With a clean filter, the total differential is approximately 41.8 kPa. The candidate must deliver the target flow with the corresponding inlet vacuum and outlet backpressure present simultaneously. A rated pressure of 100 kPa exceeding 55.8 kPa is not, by itself, evidence that the pump meets this duty.
For the selected candidate pump, the corresponding relationship between Q, inlet pressure and outlet pressure should be measured, covering clean and loaded conditions. If the flow rate cannot be achieved, first locate the main pressure drop: enlarging the thin tube, shortening the suction line, improving bottle cap ventilation, or selecting a more appropriate valve and filter are often closer to the source of the problem than directly increasing the pressure level of the pump.
5. Self-priming and pipeline design: treat the pump inlet as an independent design object
The self-priming process requires first evacuating the air in the suction pipe and pump chamber, and then establishing a continuous liquid column. Therefore, self-priming height, first liquid discharge time and stable liquid supply time are different indicators. The self-priming height in the catalog cannot be converted into a guarantee for any length of pipeline, nor can it replace startup testing after high temperatures, long suction pipes, or repeated air intake.
Why does a small inner diameter significantly increase suction losses?
Δp = 128 μ L Q / (π d⁴)The Hagen–Poiseuille relation is applicable to fully developed laminar flow, Newtonian fluids, and circular rigid straight pipes. Q uses m³/s, μ uses Pa·s, L and d use m. Elbows, valves, inlet effects, hose deformations and gas-liquid mixed flows need to be dealt with separately.Taking an approximate aqueous medium with μ = 1.0 mPa·s and ρ = 1000 kg/m³ as an example, when 120 mL/min passes through a straight pipe with a length of 1 m and an inner diameter of 2.0 mm, the calculated pressure drop is approximately 5.09 kPa, and the Reynolds number is approximately 1270. Under the same conditions, the inner diameter is increased to 3.2 mm, the calculated pressure drop is about 0.78 kPa, and the Reynolds number is about 800. Both are calculated based on laminar flow approximation, and the pressure drop differs by about 6.55 times.
This shows that the interface can be plugged into the hose, which does not mean that the resistance of the entire pipeline is appropriate. A larger pipe diameter will also increase the pipeline volume and fluid replacement volume, and it is necessary to compare the prefill time, reagent consumption and residue at the same time. If the suction side filter is chosen too fine, it will further reduce the inlet pressure after loading. It should be selected based on the actual particle risk and the allowable pressure drop.
Distinguish air ingress, dissolved-gas release and vaporization
A leaky suction joint will allow air to continue to enter. Insufficient ventilation of the bottle cap will gradually form a negative pressure in the source container, and dissolved gas may precipitate after the pressure is reduced. The local absolute pressure is too low and may also be close to the vapor pressure of the medium. Liquid temperature, volatility, and altitude all affect available suction conditions, so looking at inlet gauge pressure or whether the pump is turning alone is not sufficient.
Within permissible conditions, shorten the suction tube, raise the supply liquid level, or substitute fittings with verified air tightness and observe changes in flow and bubbles. A hose that does not visibly leak liquid may still admit air under vacuum. After self-priming, continue recording the time needed for outlet flow to stabilize.
6. High-backpressure delivery: verify pump capability and system protection together
Filtration, multi-stage valve banks, long slender lines and some spray tasks may require higher discharge pressures. The DPL30H's specification sheet lists a free flow rate of 300 mL/min and a rated pressure of 600 kPa, which makes it a candidate for a high backpressure fluid line, but the flow rate changes with pressure and cannot be written as "output 300 mL/min at 600 kPa."
To judge whether the high-pressure configuration is reasonable, you should first clarify the real required pressure and flow rate at the end, and then check the allowable pressures of connectors, valves, filters, sensors and pipelines at actual temperatures. A pump with a higher pressure rating does not automatically increase the pressure capacity of other components. Any one weaker component in the system may determine the upper limit of the work.
The control sequence should also be included in the pressure design: closing the downstream valve first and then stopping the pump may cause a short-term pressure rise; after a power outage, pressurized hoses, buffer chambers and liquids may still store energy. Appropriate pressure detection, shutdown logic, pressure relief or bypass measures need to be set based on system risks, and sensor sampling and execution delays need to be verified to be sufficient. Valve closure and failure testing should be carried out in a controlled, protected device under agreed conditions.
The medium temperature of DPL30H in this version of the specification is +5 ~ +40 ℃, and the parameter page of DPL30/DPL60 is listed as +5 ~ +80 ℃. The temperature ranges between series cannot be applied to each other; even if the liquid temperature is within the range of the pump, the environmental conditions of the joints, pipes, valves and the complete instrument still need to be checked.
7. Gas-liquid mixed suction: determine whether the liquid enters the pump chamber
There are two common structures in the waste liquid system: one allows the liquid or gas-liquid mixture to pass directly through the pump; the other collects the waste liquid into a closed container first, and then uses the pump to extract the gas above the container to establish negative pressure. The selection inputs for the two structures are different, and they cannot be verified in the same way just because they are both called "waste liquid pumps".
| System structure | Main design inputs | Abnormal conditions that require attention |
|---|---|---|
| Direct extraction of gas-liquid mixture | Liquid properties, gas-liquid ratio and changes, suction height, outlet back pressure | Liquid re-entry after long gas segments, foam, liquid slugs, residual liquid during shutdown and restart |
| Vacuum generation through a waste container | Gas phase volume, target absolute pressure, air leakage, pumping curve | Overfilling, foam bypassing the separation structure, and a wetted or blocked protective filter |
This version of the DPGL800 specification sheet lists the single-head gas flow curve and 5 L pressure building curve, which can be used for evaluation under corresponding conditions. The actual negative pressure establishment time still depends on the effective gas phase volume of the container, the connection method, pipeline resistance, leakage and working pressure. The drainage time cannot be estimated by dividing the waste liquid volume by 6 L/min.
t ≈ (V_g / S_eff) × ln(p₀ / p₁)This is a rough evacuation estimate for a closed, approximately isothermal, leak-free, and approximately constant effective pumping speed. p₀, p₁ must be absolute pressure; V_g and S_eff use matching volume and time units. When the actual pumping speed changes with pressure, the pumping speed curve integration or actual measurement should be used. The no-load 6 L/min of a single head cannot be regarded as a constant pumping speed throughout the process.For systems with continuous air intake, the negative pressure stability value is determined by the effective air extraction capacity and the air intake load. The software should distinguish between "evacuating", "working negative pressure has been reached", "not reached within the specified time" and "container full" and other states. For double-head structures, series, parallel or independent channels will change the performance and load. It is necessary to clarify the piping method and obtain the corresponding data.
For systems that need to prevent liquid from entering the pumping side, gas-liquid separation, full liquid protection and corresponding status detection should be considered structurally. Even if a candidate pump is suitable for gas-liquid mixtures, verification of foam, corrosive condensate, deposits, and prolonged liquid-laden operation cannot be omitted.
8. Wetted materials: verify the complete configuration and operating process
The liquid contact system of the diaphragm pump includes the pump head, diaphragm, valve element and sealing and connecting parts in the specific structure. Material selection needs to cover all wetted parts. You cannot judge that the entire pump is suitable for any medium just by looking at the "PTFE diaphragm". Whether the part is in contact with the media, material grade, formulation, temperature and contact time may change the results.
Taking DPL30 as an example, the selection table clearly distinguishes between EP/PS and FF/PS configurations: the former is listed as EPDM diaphragm, EPDM valve element and PPS pump head, and the latter is listed as PTFE diaphragm, FFKM valve element and PPS pump head. The material combination still needs to be evaluated in conjunction with specific chemical media; changing the diaphragm and valve element may also change the elastic response, valve opening and closing, sealing and transportation performance, so material testing and performance testing should be connected with each other.
Why pure water testing cannot represent long-term use of reagents
Solvents, salts, surfactants and cleaning components in the reagents can affect wetting, viscosity, foaming and material contact conditions. After the liquid circulates and evaporates, the concentration may increase; long-term shutdown may leave crystallization or dry residue; and different media may alternate during cleaning. These factors may cause the installed performance to deviate from the room temperature pure water test.
| Verification phase | Conditions that should be included in the test | Recommended inspection items |
|---|---|---|
| Initial screening of materials | Accurate medium composition, maximum concentration, temperature, contact time | Mass and dimensional changes, swelling, softening and cracking; check extractables and contamination as required by the project |
| Dynamic operation of the whole pump | Actual medium, working point, start-stop and gas-liquid alternation | Flow, self-priming, pressure difference, sealing, noise and current changes before and after |
| Shutdown and cleaning | Maximum downtime, residual liquid drying, actual cleaning agents and flushing procedures | Crystallization, adhesion, restart, cleaning residue and performance recovery |
| process suitability | Validation conditions compatible with real samples or analytical procedures | Effects on blank background, contamination, carryover and final instrument output |
Material soaking can help screen out obviously incompatible combinations, but it cannot fully simulate repeated bending of the diaphragm and dynamic sealing of the valve element. Observations before and after immersion should be combined with dynamic testing of the entire pump, and the materials used and complete model of the sample should be recorded. For projects where the reagent formula is confidential, the necessary information that affects the judgment of materials and working conditions can be provided under the agreed information protection arrangement.
Procurement documents should itemize the pump head, diaphragm, valve element and related sealing materials, rather than just "corrosion-resistant version". When there are different writing methods on the parameter summary page, selection table or historical data, the clarification should be completed with the specific ordering configuration and technical documents confirmed by both parties, and then the prototype and batch configuration should be frozen.
9. Motor and control: verify power supply, speed regulation and status feedback respectively
Brushed versus brushless is only the starting point for a control scheme. OEM projects must also specify supply voltage, startup conditions, harness voltage drop, drive interface, speed command, feedback and fault states. DPL30 and DPL60 datasheets list a default two-wire configuration and other lead options. A sample may differ from a generic wiring diagram, so check the complete model before connection.
| Control items | What needs to be confirmed | Verification often overlooked |
|---|---|---|
| Power supply and start-up | Rated voltage, allowable range, starting current, wiring harness and connectors | When multiple pumps or solenoid valves are started at the same time, are the pump terminal voltage and controller stable? |
| Two-wire power configuration | Start and stop methods, whether voltage regulation or chopping is allowed, and power-on default behavior | Low voltage and on-load restart to avoid driving all two-wire brushless pumps in the same way |
| Independent speed input | Level, frequency, duty cycle range, input impedance, floating behavior | Minimum stable speed, startup behavior, deadband and a defined command during power-up |
| FG speed feedback | Number of pulses per revolution, output form, pull-up requirements, sampling window | Signal interference, missed pulses at low speed, and whether feedback persists during blockage or dry suction |
| Motor direction control | DIR function and permitted logic states | After the motor is reversed, does the pump still deliver according to the one-way valve structure? It cannot be inferred that the liquid flow can be reversed. |
Speed feedback cannot directly represent flow
Q ≈ V_eff × nV_eff is the effective delivered volume per revolution and n is rotational speed. Differential pressure, gas content, fluid, valve operation and sealing affect V_eff, so constant speed does not automatically mean constant flow.DPL30H This version of the brushless wiring table stipulates that the FG outputs 3 square wave signals per revolution, so n = 60f/3 can be used to convert the rotation speed in this configuration, and the unit of f is Hz. This number of pulses cannot be generalized to other motors. Even if FG is normal, the pump may still be unable to supply liquid stably due to lack of liquid, air leakage, or abnormal valve status; flow, pressure, or liquid level feedback should be selected based on the equipment task.
The same version of DPL30H data also states that the motor stops when the PWM terminal is 0~0.25 V, full speed when it is left floating or 4.5~5 V, and supports PWM or 0~5 V speed regulation. Therefore, the control board should consider the input status during power-on, reset, cable disconnection and uninitialization. The PWM frequency, input current and output circuit requirements that are not specified in the data require further confirmation of the specific configuration and should not be copied from other models.
The number of leads in the DPGL800 photograph cannot be used as a function definition. The electrical table of this version of the specification clearly lists VCC and GND, other control or feedback requirements should be confirmed separately. For all configurations, the pump terminal voltage, speed or control command should be recorded synchronously with the actual flow rate to distinguish power supply problems, control problems and fluid circuit problems.
If closed-loop flow or pressure control is used, sensor location, signal filtering, execution delays, speed deadband, and output limiting also need to be considered. The controller should not chase each pumping pulse and continue to adjust the speed significantly; the control bandwidth should be determined based on the response speed and fluctuation range allowed by the process, and the stability after set value changes and branch switching should be tested.
10. Mechanical integration: mounting dimensions, port loads and service space
Overall length, width and height describe only the pump body envelope. Equipment layout must also allow hose bend radius, rigid-tube assembly length, connector access, harness retention, cooling and replacement. DPL30/DPL60 brushless documentation notes possible A/B motor variants with equivalent output performance but different mounting dimensions. Equal electrical performance therefore does not establish mechanical interchangeability.
This DPL30/DPL60 revision specifies connection to hose with 3.2 mm inner diameter. Hose material, wall thickness, hardness, insertion depth and retention affect air tightness and pull-out resistance; inner diameter alone is insufficient. For DPL30H rigid-tube compression fittings, check tube material, outer diameter, cut-end quality, assembly method and support so tube bending loads are not continuously transferred to pump-head ports.
The vibration of the pump can be transmitted to the housing along the bracket and pipeline, and then amplified by the large-area panel. Vibration isolators need to be evaluated together with the installation load, support stiffness and pipeline constraints; too soft supports may cause large displacements, and overly tight rigid tubes or wire harnesses may bypass the vibration isolators and transmit vibration. Comparison should be made under actual installation direction, fixing torque and housing condition.
During maintenance, residual liquid discharge, joint disassembly and assembly, priming and leak detection after pump body replacement should also be considered. If a special interface orientation or wire harness length is used, it should be recorded in the drawings and configuration files to avoid problems solved by temporary bending and manual wiring at the prototype stage from entering mass production.
11. Pulsation, noise and backflow: assess installed performance using process criteria
The diaphragm periodically changes the volume of the pump chamber, and cooperates with the opening and closing of the valve element to produce transportation. The instantaneous flow and pressure will fluctuate. After the fluctuation reaches the end, it will be affected by the elasticity of the hose, liquid compressibility, bubbles, buffer volume and valve group resistance. Qualifying the average flow rate does not mean that the instantaneous status of the nozzle or the output of the sensor must meet the equipment requirements.
Evaluate damping together with dynamic response and residual liquid
Hoses, buffer chambers or special dampers may reduce some of the fluctuations, but will also change the liquid line volume, pressure response, fluid change time and cleaning residue. The waveform before and after modification, the actual delivered volume and the liquid discharge after shutdown should be measured at the end. Relying on uncontrolled trapped air bubbles to achieve temporary smoothing can lead to inconsistent performance from start to start.
Pressure pulsation measurement should describe the measuring point, sensor range, bandwidth, sampling frequency and filtering method. A flat number on the display may simply represent a heavily filtered average; low sampling rates may also miss peaks. Sampling and sensor bandwidth should be set around the frequency of fluctuations and fault transients that need to be identified.
Verify noise and sealing during shutdown separately
When comparing noise, the measurement distance, weighting method, background noise, support, operating conditions and chassis status should be fixed. The dB value that lacks the same test conditions cannot be directly used for the silent promise of the complete instrument. If necessary, record the motor speed, pressure and vibration at the same time to distinguish motor sound, hydraulic excitation and structural resonance.
The task of the valve element in the pump is to cooperate with the pumping cycle, and it cannot be assumed that it has the long-term sealing ability of the system stop valve. Differences in liquid level, downstream pressure storage, and fluid connections may result in backflow, dripping, or siphoning during shutdowns. Shutdown hold testing should be performed in the actual pressure direction; when isolation is required, special cut-off or check components and their new pressure drop should be re-evaluated.
12. Establish a reproducible prototype test bench and acceptance method
The test should first distinguish between "performance of the pump body" and "performance of the complete instrument's fluid circuit". You can start by establishing a baseline with short tubing and known supply conditions before adding actual valves, filters, fittings, and terminals. Only change specific factors each time and record the flow rate, inlet and outlet pressure, voltage, current and temperature before and after the change to locate the differences.
Verify delivered liquid volume using the gravimetric method
Q_avg = 60 × Δm / (ρ × Δt)Δm is the mass of the collected liquid (g), ρ is the density of the medium at this temperature (g/mL), Δt is the collection time (s), and the result is mL/min. Example: 30 g is collected in 15 s and the density is 1.00 g/mL, then the average flow rate is 120 mL/min.When measuring continuous flow, the time window for starting collection after stabilization should be defined to exclude unaccounted effects of container changes, evaporation, splashing and residual drops. When measuring the volume of a single action, the start and stop processes should be retained to make it clear whether delayed dripping is included. The results of the stable section cannot be used to replace the entire action. Balance resolution, timing errors, and density estimation errors should be significantly smaller than the project's allowable errors.
In-line flow meters in pulsating liquid flows also require validation. The meter's response and sampling, range, mounting orientation, and bubble sensitivity can all affect readings, and the meter itself can also increase pressure drop. You can use the gravimetric method to check the cumulative amount over a period of time, and then compare the online total amount with the instantaneous signal to avoid misjudgment of measurement system errors as pump performance fluctuations.
| Test item | Conditions and Records | Acceptance criteria to agree before testing |
|---|---|---|
| Working point and margin | Actual medium, low level, filter load, power supply boundaries; simultaneous recording of Q, p_in, p_out | Terminal minimum/maximum flow, delivery volume and completion time |
| Self-priming and restart | Test separately on dry pipes, wet pipes, after shutdown, and after changing bottles and air intake. | First liquid discharge time, stabilization time, allowed number of retries |
| Sealing and shutdown hold | Positive pressure, negative pressure, liquid level difference and shutdown holding time | Allowable leakage, air ingress, backflow or dripping volume |
| Electrical and Control | Cold and warm startup, simultaneous loads and abnormal control signals | Power supply stability, default state, feedback validity and fault response |
| Gas-liquid suction | Representative gas section, liquid section, foam and gas phase volumes | Suction completion time, residual liquid, negative pressure establishment and recovery |
| Process effect | Actual cleaning objects, reagents and operating procedures | Cleaning residue, carryover and allowable changes in instrument output |
Each record should retain at least the sample number, complete model, material and motor configuration, fluid circuit diagram, media batch, temperature, power supply, software version, instrument calibration status and original data. Comparative samples need to use the same test conditions; saving only an average will lose clues to analysis start-up anomalies, drift, and sporadic failures.
Assess the average, sample-to-sample variation and worst-performing sample. Define acceptance thresholds from equipment requirements before testing; do not derive passing criteria from the observed samples afterward. Investigate failures by checking power, control, suction, discharge, sealing and materials, then retest the revised configuration.
13. Service life and reliability: relate continuous running hours to the actual duty profile
DPL30, DPL60, and DPL30H are listed in this version of brushed 3000 h and brushless 10000 h respectively, under the conditions of rated voltage and continuous operation; DPGL800 is listed as 10000 h. They are life indicators under corresponding data conditions and cannot be directly regarded as the overall machine life or warranty period under customer media, arbitrary back pressure and frequent start and stop conditions.
The whole machine may only run for a few hours a day, but contains a large number of short-cycle starts and stops; it may also run continuously but with high pressure, or it may be parked in a medium that is prone to crystallization for a long time. The diaphragm, valve element, motor, interface and control circuit bear different loads, and a duty profile needs to be established.
D = t_on / (t_on + t_off)；T_run = N_cycles × t_onD is the duty cycle, T_run is the accumulated running time, t_on and t_off use the same unit. In addition to the accumulated time, it is also necessary to record the number of starts and stops, pressure, temperature, medium and length of each operation. Life cannot be calculated based on duty cycle alone.Durability verification should re-test the operating point flow rate, self-priming time, sealing, starting, current and temperature rise in stages during operation. The pump is still rotating, but the flow rate is lower than the equipment requirements, which is also a functional failure. Termination conditions such as flow drift, leakage, inability to restart, control failure and process failure should be written in advance.
Accelerated testing needs to explain the relationship between acceleration factors and failure mechanisms. Simply increasing the temperature, pressure or concentration may introduce failures that do not exist in normal use, and the on-site life cannot be converted into multiples at will. The number of samples and test duration should be determined based on risks and statistical objectives. Running one sample is not enough to prove the life distribution of all batches of products.
Performance comparisons should also distinguish conditions. For example, if the original pump and the candidate pump meet the same working conditions on the same complete instrument, it can only prove the adaptation results under verified conditions; similar appearance, the same rated flow rate, or passing a round of short-term testing are not enough to describe a comprehensive equivalent replacement.
14. Standard selection, configuration adaptation and custom development
FOREACH provides support for microfluidic core components and fluid circuit solutions. The publicly introduced engineering collaboration includes prototype verification, parameter matching, and adjustment of solutions based on space, interface, media and control requirements. For a specific OEM diaphragm pump project, it is recommended to first evaluate whether the existing model can cover the task, then discuss configuration adaptation, and finally determine whether dedicated development is required.
| Integration level | What needs to be clarified | Suitable basis for delivery |
|---|---|---|
| Standard product selection | Do the existing models, voltages, motors, materials and interfaces cover the working conditions? | Formal specification, complete order model, sample configuration and verification results |
| Configuration adaptation | Whether the cable outlets, interface directions, materials or other configurations listed in the data are suitable for the selected model | Confirmed drawings, wiring definitions, configuration list and retest scope |
| Project custom development | Performance, space, interface or control objectives that cannot be met with standard solutions | Feasibility assessment, development boundaries, sample plan, acceptance conditions and division of labor between the two parties |
Changing the interface direction mainly solves assembly problems; changing materials may affect chemical compatibility and pumping performance at the same time; changing motors and control methods will affect power supply, heat dissipation, noise and feedback logic. Even if the adjustment seems local, identify the affected metrics and determine which validations need to be repeated.
If the project also includes valves, fittings, piping, or pressure testing, they can be evaluated together on the same fluid circuit diagram. The value of system matching lies in reducing omissions between interfaces and working conditions. The scope of work, available configurations, delivery cycle, quantity and acceptance requirements of any integration solution should still be subject to the confirmation results of the specific project.
15. From prototype to production: freeze a traceable configuration and acceptance criteria
After the prototype test passes, the next step should be to transform "This sample can work" into "Subsequent supply can be accepted under the same technical conditions." The following is the recommended project promotion method. The specific process and responsibilities should be jointly determined by the equipment factory and FOREACH in conjunction with the project.
- Freezing requirements: clarify the fluid circuit diagram, medium, working point range, rhythm, environment, target life and fault status.
- Confirm the sample: record the complete model, material, motor, interface, direction, wiring harness, drawing and technical document version.
- Complete verification: Cover baseline, boundary conditions, process effects and durability tests, and retain failure analysis and revision records.
- Run a pilot installation batch: examine sample variation, assembly efficiency, tube-connection consistency, test fixtures and service replacement.
- Agree on batch acceptance: distinguish between incoming material inspection, factory testing and type verification, and clarify samples and criteria, recording and traceability methods.
- Manage configuration changes: agree notification, assessment and revalidation requirements for changes to materials, diaphragms, valve elements, motors, leads, fittings or manufacturing processes that affect performance.
For production supply, a short purchasing description is acceptable only when the technical attachments are complete. “DPL30 brushless pump” alone does not identify voltage, wetted materials, leads or port details. Acceptance should cover more than appearance and free flow: specify representative performance conditions according to project risk and preserve their link to design validation.
Information to include in an OEM request to FOREACH
| Requirement Category | Suggested submissions |
|---|---|
| Equipment and Actions | Equipment type, process the pump is responsible for, each volume, effective action time, and branches working at the same time |
| Fluid | Composition or necessary chemical information, concentration, temperature, viscosity, particles, foam, cleaning agent and shutdown residual fluid |
| fluid path | Schematic, tubing and inner and outer diameters, length, valves/filters/fittings, liquid level differential, source vessel venting and terminal pressure |
| Performance | Minimum and maximum working flow, inlet and outlet pressure range, allowable pulsation, self-priming/evacuation time, residual liquid and sealing requirements |
| Electrical and Structural | Power supply, control input, feedback, starting conditions, installation diagram, interface orientation, wiring harness and maintenance space |
| Validation and supply | Duty profile, acceptance criteria, sample plan, expected demand, development stage, production consistency and change requirements |
When the information is incomplete, you can first provide equipment usage, existing fluid circuit diagrams, and observed problems. Engineering communication should gradually transform unknown conditions into measurement or confirmation tasks, and ultimately form candidate configurations and corresponding verification plans. Only the FOREACH diaphragm pump selected in this way can establish a clear technical correspondence with the liquid supply, cleaning or pumping tasks of the instrument.
16. Product information and further reading
The product parameters in this article are based on the following FOREACH Chinese specifications. The parameter page is used to understand the performance conditions, the selection table is used to confirm the configuration, and the dimensional drawing and electrical table are used for installation. The file version should be checked before ordering; when special media, control or interface adjustments are involved, confirmation information of the corresponding configuration should be obtained.
DPL30 Chinese datasheet | PS-150B-2412-00001, A04: performance, materials and lead definitions
DPL60 Chinese datasheet | PS-150B-2412-00002, A02: performance, dimensions and model selection table
FOREACH product specifications and catalogs
FOREACH microfluidic core components and engineering support
Causes and improvement methods of diaphragm pump flow pulsation
Technical FAQ: FOREACH diaphragm pump OEM integration
Does FOREACH diaphragm pump OEM integration always require a new pump design?
Not necessarily. Standard models should be evaluated first with clear media, operating points, interfaces and control requirements. When standard solutions are insufficient, discuss optional configurations or project customization, and confirm the impact of adjustments on performance, structure, and verification scope. Available configuration and development boundaries need to be confirmed on a project-by-project basis.
The device requires 120 mL/min, is it enough to choose the DPL30 with 300 mL/min without load?
You cannot judge based on free flow rate alone. It is necessary to check the available flow rate of the candidate pump under actual inlet negative pressure, outlet back pressure, media temperature, filter load and power supply conditions, and then compare it with the target value and margin requirements. The most adverse operating conditions and criteria should be defined before verification.
Can the 600 kPa of the DPL30H be understood to mean that there is still 300 mL/min at that pressure?
No. 300 mL/min is the free flow rate listed in the specification, and 600 kPa is the rated pressure. The flow rate under the corresponding pressure should be viewed in the corresponding curve and verified in the actual fluid circuit. The rated pressure cannot be directly regarded as a condition that allows long-term closed valve operation.
Can the DPGL800 double head be directly calculated based on 12 L/min liquid pumping?
No. 6 L/min refers to the single-head no-load gas flow rate, not the liquid delivery flow rate. The performance of double heads in series, parallel or independent use depends on the connection method, pressure and load; the pumping time needs to be tested in the actual gas-liquid state and pipeline.
Can the speed feedback of a brushless pump be used to determine whether the liquid is being delivered normally?
Speed feedback can explain the motor rotation status, but it cannot independently prove that the liquid flow is normal. There may still be a speed signal when there is a lack of fluid, air leakage or valve element abnormality. Appropriate observations such as flow, pressure, liquid level or bubbles need to be added in conjunction with the equipment tasks.
Can I eliminate media validation by choosing PTFE and FFKM?
No. It is still necessary to confirm the complete material combination of the pump head, diaphragm, valve element and other wetted parts, and cover the actual medium composition, concentration, temperature, shutdown and cleaning process. After the material passes the preliminary screening, the dynamic performance and process applicability of the entire pump should be verified.
Can the 10,000 h in the specification be directly used as the OEM machine life?
No. This corresponds to the rated voltage and continuous operating conditions listed in the specification sheet. The medium, pressure, temperature, number of starts and stops, and shutdown conditions of the complete instrument may be different. The applicability should be determined through the duty profile, functional failure criteria, and durability verification.
After the OEM project confirms the model, what information still needs to be frozen?
It is recommended to freeze the complete ordering configuration, material list, installation diagram, interface and line sequence, control requirements, fluid circuit conditions, acceptance methods and sample records, and also agree on how batch traceability and configuration changes that affect performance will be evaluated and re-inspected.